CATALYTIC DESALINATION USING CO2-RESPONSIVE ORGANIC COMPOUNDS

Title:

CATALYTIC DESALINATION USING CO2-RESPONSIVE ORGANIC COMPOUNDS

Document Type and Number:

WIPO Patent Application WO/2020/094632

Kind Code:

Abstract:

Desalination, in principle, can offer unlimited amounts of drinkable water by removing salt from seawater or brackish water. The present invention relates to a dramatical reduction of salinity by using carbon dioxide and organic C02-responsive materials. The novel CO2-promoted desalination is using reusable organic molecules - namely, diamines. Upon reacting with CO2 in water, functionalized diamines spontaneously form an insoluble carbamate where salt is incorporated during the precipitation, thereby reducing the salinity of the aqueous media. Thus, the present invention relates to processes for the desalination or water purification, particularly using alkyl- chain decorated organic diamines and CO2. Furthermore, the present invention relates to processes to capture ions and polar substances, in particular NaCI and other salts, from seawater or aqueous solutions.

Inventors:

LEE JIWOONG (DK)

Application Number:

PCT/EP2019/080221

Publication Date:

May 14, 2020

Filing Date:

November 05, 2019

Export Citation:

Click for automatic bibliography generation Help

Assignee:

COWATECH APS (DK)

International Classes:

C02F1/52; C02F1/68; C02F1/66; C02F103/08

Domestic Patent References:

WO2018146507A1	2018-08-16
WO2014188115A1	2014-11-27

Foreign References:

EP0578323A2	1994-01-12
US20110198292A1	2011-08-18
US5547586A	1996-08-20
GB576969A	1946-04-30
US2445669A	1948-07-20
US2363020A	1944-11-21
US20140076810A1	2014-03-20

Other References:

R. F. SERVICE, SCIENCE, vol. 313, 2006, pages 1088
ENERGY PROCEDIA, vol. 63, 2014, pages 7947 - 7953
BRYCE DUTCHERMAOHONG FANARMISTEAD GRUSSELL, ACS APPLIED MATERIALS & INTERFACES, vol. 7, no. 4, 2015, pages 2137 - 2148
J.-W. LEER. KLAJN, CHEM. COMMUN., vol. 51, 2015, pages 2036 - 2039
LECLAIR, CHEMICAL SCIENCE, 2017
M. ELIMELECH, DESALINATION, 2005
X. HU, CHEM. COMMUN, 2013
CHEM. REV., vol. 112, 2012, pages 724 - 781
NATURE, vol. 519, 2015, pages 303
J. AM. CHEM. SOC., vol. 139, 2017, pages 13541

Attorney, Agent or Firm:

AERA A/S (DK)

Download PDF:

View/Download PDF PDF Help

Claims:

CLAIMS

1. A method for desalination of an aqueous solution comprising a salt of formula ⁺Na Cl (mixture A), comprising the steps; i) contacting an amine of formula (I) with mixture A to generate an aqueous mixture comprising amine and salt (mixture B), ii) contacting mixture B with CO2 for a sufficient time period to co-precipitate with the amine of formula (I), ⁺Na, and Cl to generate a precipitate (Z), and iii) isolate the precipitate (Z) to obtain an aqueous mixture C of lower salinity than aqueous mixture A, wherein the amine formula (I) is defined by:

Formula (I) wherein, R1 and R2 are Me,

R₃ is H,

X is CH₂,

R4 and R5 are H, n is 3, and m is an integer from 7-15 included.

2. The method according to claim 1 , wherein the aqueous solution is selected from the group consisting of seawater, brackish water, saline water, brine, and salt-enriched water.

3. The method according to claims 1-2, wherein the salt concentration of mixture C is no more than 5g of total dissolved NaCI per litre of the aqueous solution.

4. The method according to claims 1-3, wherein the precipitate is separated by filtration, gravimetrical separation, centrifugation or decantation.

5. A diamine formula (I) defined by:

Formula (I) wherein,

Ri and F¾ are Me,

R₃ is H,

X is CH₂,

R4 and R5 are H, n is 3, and m is an integer from 7-15 included

6. The diamine of claim 5, wherein m is 1 1 , and the diamine is of formula C12:

Formula C12.

7. One or more of the diamines according to claims 5-6, for use in a method of desalination according to claims 1 -4.

8. A kit for desalination comprising a compound of formula (I) as defined in any of the previous claims.

9. The kit according to claim 8, herein the kit is an emergency kit.

10. The kit according to claims 8-9, herein the kit is portable.

Description:

Catalytic Desalination using C0 ₂-responsive organic compounds

FIELD

Desalination, in principle, can offer unlimited amounts of drinkable water by removing salt from seawater or brackish water and can furthermore be highly relevant in a high number of industrial applications where the removal of salt from aqueous media is desirable. The present invention relates to a technology that can provide a dramatical reduction of salinity by using carbon dioxide and organic CCh-responsive materials. The novel CCh-promoted salinity reduction technology is using reusable organic diamines. Upon reacting with CO2 in water, or other aqueous media or organic solvents, the functionalized diamines spontaneously form an insoluble carbamate where salt is incorporated during the precipitation, thereby reducing the salinity of the aqueous media. Thus, the present invention relates to processes for the desalination, particularly using alkyl-chain decorated organic diamines and CO2. Furthermore, the present invention relates to processes for capturing ions and polar substances, in particular NaCI and other salts, from seawater or other aqueous media.

BACKGROUND

Water is arguably one of the most important substances on Earth. However, recent global climate changes are seemingly accelerating the unpredictability of secure water supply sources - even in developed countries, threatening society’s sustainable growth. This global societal issue is now entangled together with many other problems, including environment sustainability, public health and energy security.

Due to the abundance of seawater and easy access to coastlines around industrialized zones, desalination of seawater is one of the most sustainable approaches to provide drinkable water or water for industrial and agricultural purposes where the salt concentration is lower than what is found in the feedwater. Additional sources of feedwater may include brackish water, seawater, wells and surface (rivers and streams) water. Through the water desalination process dissolved salts are separated and removed from the water. However, the current state-of-the-art desalination facilities heavily depend on the use of highly intensive energy sources, such as electricity, for distillation or reverse osmosis membrane processes. Distillation can provide water from seawater, or other saline feedwater sources, which lives up to the low salinity demands. However, considering the high heat capacity of water, it is not a viable option to use distillation in the case of large quantity of industrial process water or even drinkable water production. Also, high hydration energy of salts, mainly NaCI (consisting 85.6% of salts in seawater), is the key issue preventing energy-efficient salt removable processes. In this context, reverse osmosis and membrane distillation processes have been the prime technology, thereby minimizing energy penalty during the saline removing processes by taking advantage of porosity of membranes. Some efficient membranes are already being used to efficiently permeate water molecules through the membrane interfaces, allowing the separation of salts from saline water feeds. However, once again, this technology requires high-intensity energy and/or high pressure, hampering its adaptation in rural areas, emergency situations (such as natural disasters draught areas or in lifeboats at sea), at sea based industrial or leisure activities e.g. offshore oil rigs and ships, and in less developed countries to relive water-stressed situations. In addition, the high-intensity energy requirement is environmentally and financial burden even in developed countries.

A general overview on desalination can be found in R. F. Service, Science 2006, 313, 1088.

Forward osmosis can also be a solution to meet the demand for desalination of saline water by exposing a membrane pouch containing solutions with high chemical potential (usually sugar and other minerals), to draw only water through the membrane into the pouch. This is a particularly important technology under emergency situation since it can provide drinkable water where only saline water is available. However, the process is extremely time-consuming (around 10 hours to draw approx. 500 ml_ of purified water). Therefore, a further development of water desalination processes is highly desirable.

In addition to the above needs for desalination, many industrial processes either require or will have a benefit from lowering the salinity of aqueous media or even fully removing the salt from the aqueous media, e.g. in cases where the aqueous media is waste-water.

For decades organic molecules have been a primary tool to adjust properties and functions of materials. More specifically, certain CO2 capture processes utilize diamines and amino alcohols which can adsorb carbon dioxide from low concentration feeds, forming various ammonium carbonate and carbamate salts. These processes occur in aqueous solution. Accordingly, the process requires high energy to recover the toxic and corrosive amine solution during the regeneration step via evaporating the captured CO2, thereby liberating and sequestrating CO2. The energy required for this regeneration step is provided in the form of heat in the presence of water. As water has high heat capacity (1 kcal/gram/°C) which is higher than any other common substances, the process is very energy intensive. Nevertheless, amine solutions are the choice for carbon capture and sequestration process, due to the high specific binding affinity toward CO2 with amino alcohols and diamines for amine scrubbing.

For reduction of salinity, organic molecules, more specifically diamines and aminoalcohols, have been applied as liquid materials for rejecting brine in the presence of CO2. The CCh-amine interactions render precipitation of sodium bicarbonate and carbonate salts with good purity. However, this process is not feasible in terms of desalination due to the fact that the chloride anion and the soluble organic amines are still in aqueous solution, hampering its application in the production of potable water (see Energy Procedia 63 (2014) 7947 - 7953).

Organic amines can reversibly complex with carbon dioxide, resulting in the thermally labile carbamate salt. This reaction is more prominent in the case of diamines, because of the intramolecular stabilization effect provided by hydrogen bonding and ion-ion interactions.

Under reduced pressure or elevated temperature, the dissociation of CO2 occurs spontaneously, and the parent diamines are regenerated. This reversible carbon dioxide capture process has been well studied and applied in many fields, including the carbon capture processes (see Bryce Dutcher, Maohong Fan, and Armistead G. Russell, ACS Applied Materials & Interfaces 2015 7 (4), 2137-2148). However, the polar diamine-CCh complex has not been utilized to capture polar species, besides the studies on CCh-induced self-assembly processes. The reported CO2- responsive autonomous aggregation (or precipitation) was shown to be powered by polarity alteration of the monomeric entity (see J.-W. Lee, R. Klajn, Chem. Commun. 2015, 51, 2036-2039).

Organic diamines are well known to be complexed with CO2, thereby generating the diamine-C0 ₂ adducts. The obtained adducts can be applied in self-assembly, heavy metal capture and soda production and baking powder production. The use of diamine-C0 ₂ adducts has been extended to C0 ₂-capture processes, aiming at reducing CO2 concentration from flue gas and other CO2- containing gas mixture sources.

Recently, a group reported that polymeric amines and ethylene (C2)-based diamines are applicable to capture metal ions in the presence of CO2, by taking advantage of CC -amine interactions (LeClair 2017 Chemical Science). The majority of work from this group focused on the formation of molecular network using aldehydes, as molecular linker, to construct complicated networks of diamine-CCh adducts, which have particular affinity toward transition metals (see for example WO2014/1881 15). The reported processes were performed in organic solvents (methanol and ethanol), such that the construction of supramolecular structures can be controlled to capture heavy metals. The reported procedure, however, has not been performed in aqueous solutions, therefore, it is difficult to apply the technology in desalination or water purification processes. The reported procedure is also limited to a few examples of heavy metals including lanthanide and transition metals such as La, Lu, Pr, In, and Nd. Efforts have also been devoted to making a breakthrough in the desalination process, by employing for example ammonia as a responsive unit to increase chemical potential of a draw solution, which afterwards can be heated up to remove ammonia and CO2 simultaneously providing desalinated water via forward osmosis (M. Elimelech 2005, Desalination). However, this procedure is limited to the volatile amine source, namely ammonia, which can be highly toxic in aqueous environment.

To solve this limitation, polymeric diamines have been utilized in forward osmosis but only with little success due to the limitation in producing polymeric diamines and the low diffusion rate (G. Jessop US 2014/0076810 A1 , X. Hu, 2013, Chem. Commun). The challenge lays on the ground of high solubility of NaCI and other salts in water, therefore, the solubilisation of salts is almost irreversible, resulting in the high energy input required to perform the desalination. The high energy sources, e.g. heat, pressure and chemical potential, can be replaced by using sustainable solar and wind powered energy sources, which, however, require more sophisticated infrastructures and additional technological investments. Also, the application of conventional desalination processes, mainly membrane distillation and reverse-osmosis salt rejection methods, is not straightforward in third world countries with low industrial infrastructures.

Additionally, desalination to relieve emergency water-stressed circumstances is a highly demanding technology due to the unpredictable climate change, increasing potential instability in many regions and societies in the world limiting the access to secured natural water resources.

A high desalination rate, or high response rate, is necessary to realize ideal desalination processes, implying that the reduction of salinity should be performed under kinetically favoured pathways. Also, it should be noted here that the recyclability of the materials should be considered to eventually reduce environmental impact of the technology to provide sustainable desalination methodology.

The present invention relates to diamines and methods focussed on solving challenges related to desalination.

SUMMARY

The present inventors have invented an energy efficient and fast method to desalinate saline aqueous solutions by the surprising finding that a CC -responsive self-assembly process, which are previously only know to happen in non-aqueous solutions, can induce co-precipitation of solubilized ions (salts) and other substances in aqueous solutions. The water desalination processes therefore separate dissolved salts (solubilized ions) and other minerals from water.

The main component of said desalination process is the amine structures described herein. During the energy-efficient desalination process, the organic CC>2-responsive material (the amines of formula (I)) captures the greenhouse gas CO2, as well as the solubilized ions (salts) in the aqueous solution. After the solubilized ions (salts) have been co-precipitated with CO2 and the organic CO2- responsive material, the desalinated aqueous solution (e.g. water) can be isolated in one fraction, and the organic CC>2-responsive materials of the present invention can be isolated in a second fraction. This second fraction comprising the organic CC>2-responsive material complexed with the solubilized ions (salts) and CO2 can be re-activated by simply reducing the pressure and/or using mild heat. Upon such re-activation, the amine complex releases CO2 as well as the captured solubilized ions (salts), such as NaCI. The re-activation of the organic CC>2-responsive material completes the catalytic cycle of the desalination process, where after the cycle can be repeated by reacting the organic CC>2-responsive material with the original desalinated aqueous solution if further desalination is required to reach a desired salinity of the aqueous solution. Alternatively, the re-activated organic CC>2-responsive material can used in a second or further batch of an aqueous solution comprising solubilized ions (salts).

In its broadest aspect, the present invention relates to a method for reduction of the amount of salts in an aqueous solution comprising said salts (as solubilized ions) having formula ⁺M _a Xb (mixture A), comprising the steps; (i) contacting an amine of formula (I) with mixture A to generate an aqueous mixture comprising amine and salts (mixture B), ii) contacting mixture B with CO2 for a sufficient time period to co-precipitate with the amine of formula (I), ⁺M _a, and Xb to generate a precipitate (Z), and iii) isolate the precipitate (Z) to obtain an aqueous mixture C of lower salinity than the aqueous mixture A, optionally with a repeat or re-cycling of steps (I) to (III), wherein the amine formula (I) is defined by:

Formula (I) wherein, Ri , R2 and R3 are selected independently from H, Me, Et, n-Pr, i-Pr, n-Bu, i-Bu, t-Bu, Ph, Benzyl, and Aryl; X is selected from C=0, C=NH, C=S, CHF, CH2 and CF2; R4 and Rs are selected independently from CH3, H and F; n is an integer from 1-4 included; m is an integer from 3-18 included; and wherein ⁺M _a is a cation ⁺M with a indicating the number of cations in the salts; and Xb is an anion X with b indicating the number of anions in the salts.

In an embodiment of the present invention ⁺M is selected from the group consisting of a monovalent metal cation, a divalent metal cation, a trivalent metal cation, and an ammonium ion.

In another embodiment of the present invention is the monovalent metal cation selected from the group consisting of Li ⁺, Na ⁺, K ⁺, Rb ⁺, Cs ⁺, Fr ⁺, Ag ⁺ and Cu ⁺. In a further embodiment of the present invention is the divalent metal cation selected from the group consisting of Be ²⁺, Mg ²⁺, Ca ²⁺, Sr ²⁺, Ba ²⁺, Ra ²⁺, Zn ²⁺, Mn ²⁺, Co ²⁺, Cr ²⁺, Cr ³⁺, Ni ²⁺, Cu ²⁺, Cu ^{1 +}, Ra ²⁺, Cd ²⁺ and Pb ²⁺. In an embodiment of the present invention is the trivalent metal cation selected from the group consisting of Al ³⁺, Ga ³⁺, Tl ³⁺, Fe ²⁺, Fe ³⁺, Ru ³⁺, Sc ³⁺, Rh ³⁺, ln ³⁺, Yb ³⁺ and Hg ²⁺.

In a further embodiment of the present invention ⁺M is selected from the group consisting of an ammonium ion, a sulfonium ion and a phosphonium ion. In another embodiment of the present invention is Xb a monovalent halogen selected from the group consisting of F , Cl , Br , I , CN (cyanide), OCN (cyanate), NO3 (nitrate), NO ₂ (nitrite), HS0 ⁴ (hydrogen sulfate), H ₂PO ₄

(dihydrogen phosphate). CIO3 (chlorate), CIO ₄ (perchlorate), OCI (hypochlorite), acetate, SCN (thiocyanate), OHN (hydroxide), Mn0 ₄ (permanganate) and divalent anions selected from the group consisting of SO4 ² (sulfate), S2O3 ² (thiosulfate), SO3 ² (sulfite), HPO4 ² (hydrogen phosphate), CrC ² (chromate), Cr207 ² (dichromate), and trivalent anion PO ₄ ³ (phosphate). In a further embodiment of the present invention is Xb phosphate. In another embodiment of the present invention is Xb carbonate. In an embodiment of the present invention is Xb sulfate. In a further embodiment of the present invention is Xb bicarbonate.

In an embodiment of the present invention is the salt selected from the group consisting of NaCI, KCI, LiCI, LiBr, Lil, LiF, NaF, NaBr, Nal, KF, KCI, KBr, Kl, Na ₂S0 ₄, K2SO4, MgSC , CaF ₂, CaCI ₂, CaBr2, Ca , CaSC . In another embodiment of the present invention the salt is selected from the group consisting of sodium, potassium, calcium, magnesium, chloride, sulphate, bicarbonate, carbonate and nitrate. In another embodiment of the present invention is the salt NaCI.

In an embodiment of the present invention is n in formula (I) selected from the group consisting of 1 , 2, 3, and 4. In a further embodiment of the present invention is n 1. In an embodiment of the present invention is n 2. In another embodiment of the present invention is n 3. In an embodiment of the present invention is n 4.

In another embodiment of the present invention is m in formula (I) selected from the group consisting of 3, 4, 5, 6, 7, 8, 9, 10, 1 1 , 12, 13, 14, 15, 16, 17 and 18. In a further embodiment of the present invention is m an integer in the interval from 6-18. In another embodiment of the present invention is m 6. In a further embodiment of the present invention is m 7. In another embodiment of the present invention is m 8. In an embodiment of the present invention is m 9. In a further embodiment of the present invention is m 10. In another embodiment of the present invention is m 11. In a further embodiment of the present invention is m 12. In another embodiment of the present invention is m 13. In a further embodiment of the present invention is m 14. In an embodiment of the present invention is m 15. In another embodiment of the present invention is m 16. In a further embodiment of the present invention is m 17. In an embodiment of the present invention is m 18.

In an embodiment of the present invention m has a degree of unsaturation of 2. In an embodiment of the present invention m has a degree of unsaturation of 3. In a further embodiment of the present invention m has a degree of unsaturation of 4.

In a further embodiment of the present invention formula (I) is any of the compounds listed in figure 1.

In a further embodiment of the present invention Ri is H. In another embodiment of the present invention Ri is Me. In an embodiment of the present invention is Ri Et. In another embodiment of the present invention Ri is n-Pr. In a further embodiment of the present invention Ri is i-Pr. In an embodiment of the present invention Ri is n-Bu. In a further embodiment of the present invention Ri is i-Bu. In an embodiment of the present invention Ri is t-Bu. In another embodiment of the present invention Ri is Ph. In a further embodiment of the present invention Ri is H Benzyl. In an embodiment of the present invention Ri is Aryl. In a further embodiment of the present invention R _å is H. In an embodiment of the present invention R2 is Me. In a further embodiment of the present invention R ₂ is Et. In another embodiment of the present invention R ₂ is n-Pr. In an embodiment of the present invention R ₂ is i-Pr. In a further embodiment of the present invention R ₂ is n-Bu. In another embodiment of the present invention R ₂ is i-Bu. In an embodiment of the present invention R ₂ is t-Bu. In a further embodiment of the present invention R ₂ is Ph. In an embodiment of the present invention R ₂ is Benzyl. In another embodiment of the present invention R ₂ is Aryl. In a further embodiment of the present invention R3 is H. In a further embodiment of the present invention R3 is Me. In an embodiment of the present invention R3 is Et. In an embodiment of the present invention R3 is n-Pr. In a further embodiment of the present invention R3 is i-Pr. In another embodiment of the present invention R3 is n-Bu. In a further embodiment of the present invention R3 is t-Bu. In an embodiment of the present invention R3 is Ph. In an embodiment of the present invention R3 is Benzyl. In another embodiment of the present invention R3 is Aryl. In an embodiment of the present invention X is C=0. In a further embodiment of the present invention X is C=NH. In a further embodiment of the present invention X is C=S. In an embodiment of the present invention X is CHF. In another embodiment of the present invention X is CH ₂. In an embodiment of the present invention X is CF ₂. In a further embodiment of the present invention R ₄ is CH3. In an embodiment of the present invention R4 is H. In a further embodiment of the present invention R4 is F. In another embodiment of the present invention Rs is CH3. In a further embodiment of the present invention Rs is H. In a further embodiment of the present invention Rs is F.

In a further embodiment of the present invention the aqueous solution is selected from the group comprising aqueous solutions such as of seawater, brackish water, well water, surface water (from rivers or streams), wastewater, industrial feed water, industrial process water, saline water, brine salt-enriched water, and draw solutions in FO (Forward Osmosis).

A draw solution is a high concentrated salt solution used in Forward Osmosis to draw water molecules through a membrane which retains larger molecules like salts and/or organics.

In an embodiment of the present invention the aqueous solution is seawater. In a further embodiment of the present invention the aqueous solution is brackish water. In a further embodiment of the present invention the aqueous solution is wastewater. In a further embodiment of the present invention the aqueous solution is brine. In a further embodiment of the present invention the aqueous solution is industrial feed water. In a further embodiment of the present invention the aqueous solution is industrial process water.

In another embodiment of the present invention the salt concentration of mixture A is 0.05 - 40% salinity level (equal to 0.1 - 400 g/L or g/kg). In a further embodiment of the present invention the salt concentration of mixture C is less than 0.05% salinity level (fresh water: less than 0.5 g/L). In an embodiment of the present invention the salt concentration of mixture C is above 0.05% but less than 3% salinity level (brackish water: 0.05-3% salt, 0.5 - 30 g/L). The salinity level is measured at 20 degrees C.

In a further embodiment of the present invention the aqueous solution (mixture A) furthermore comprises a compound selected from the group consisting of organic amines (formula (I)), ammonium salt of formula (I), ammonium carbamate of formula (I), ammonium carbonate salt of formula (I), and ammonium bicarbonate salt of formula (I).

In another embodiment of the present invention the salt concentration of mixture C is no more than 80 % of the salt concentration of mixture A. In another embodiment of the present invention the salt concentration of mixture C is no more than 70 % of the salt concentration of mixture A. In another embodiment of the present invention the salt concentration of mixture C is no more than 60 % of the salt concentration of mixture A. In another embodiment of the present invention the salt concentration of mixture C is no more than 50 % of the salt concentration of mixture A. In another embodiment of the present invention the salt concentration of mixture C is no more than 40 % of the salt concentration of mixture A. In another embodiment of the present invention the salt concentration of mixture C is no more than 30 % of the salt concentration of mixture A. In another embodiment of the present invention the salt concentration of mixture C is no more than 20 % of the salt concentration of mixture A. In another embodiment of the present invention the salt concentration of mixture C is no more than 15 % of the salt concentration of mixture A. In another embodiment of the present invention the salt concentration of mixture C is no more than 10 % of the salt concentration of mixture A. In a further embodiment of the present invention the salt concentration of mixture C is less than 5 g/L of total dissolved salt).

In an embodiment of the present invention mixture C comprises water, salts, including NaCI, and/or other remaining ionic salts and polar molecules, amine based on formula (I), and related ammonium salts based on formula (I).

In a further embodiment of the present invention the contacting step described in step i) is done by e.g. a technique selected from the group comprising mixing, shaking, adding, slurring, or injecting the diamine based on formula (I) into mixture A.

In another embodiment of the present invention the amines, more specifically the diamine in mixture A is soluble, insoluble, homo- or heterogenous.

In a further embodiment of the present invention the CO2 concentration is in the range from 4 ppm to 100 % pure. In a further embodiment of the present invention the CO2 concentration is 20 ppm to 100 ppm.

In another embodiment of the present invention the CO2 is gaseous. In an embodiment of the present invention the CO2 is naturally occurring CO2 extracted from the surrounding air. In a further embodiment of the present invention the CO2 is from exhaled breath from a human. In a further embodiment of the present invention the CO2 is from compressed CO2 cylinders.

In another embodiment of the present invention the sufficient time period in step (ii) is the amount of time it takes to reach a concentration of CO2 of 2-3 equivalents to the molarity of diamines.

In a further embodiment of the present invention, the sufficient time period described in step ii) is any time period in the range from 5 seconds to 15 minutes. The time period described in step ii) can be 2 minutes to 30 minutes. The time period described in step ii) may be 1 minute to 10 minutes. The time period described in step ii) can be 10 seconds to 20 minutes. The time period described in step ii) can be 5 minutes to 30 minutes. The time period described in step ii) can be 5 seconds to 15 minutes. The time period described in step ii) can be 1 minute to 10 minutes. For 1 L seawater desalination (35g/L) 100g diamine is needed, and at least 1 equivalent of CO2. This means 9 L of CO2 at 1atm, room temperature, or 16 mL of CO2 (20bar pressurized). In one embodiment of the present invention is the amount of CO2 to diamine equimolecular. In another embodiment is the amount of CO2 to diamine an excess of CO2 compared to diamine. In a further embodiment is the amount of CO2 at least an excess of 2 times the molar amount of diamine. In a further embodiment is the amount of CO2 at least an excess of 3 times the molar amount of diamine. In a further embodiment is the amount of CO2 at least an excess of 4 times the molar amount of diamine. In a further embodiment is the amount of CO2 less than an excess of 4 times the molar amount of diamine. In a further embodiment of the present invention the precipitate Z comprises organic diamines based on formula (I) comprising carbon dioxide, salts and polar substances, which originated from mixture A.

In a further embodiment of the present invention the precipitate Z is a mixture of the diamine, the diamine-C0 ₂ adducts, the diamine-salt complex, diamine-based ammonium salts of bicarbonate, carbonated, and sodium chloride.

In another embodiment of the present invention the precipitate is separated by filtration, gravimetrical separation, centrifugation or decantation.

The filtration can be micro-, ultra- or nanofiltration, most preferable ultrafiltration.

In an embodiment of the present invention the method is conducted at room temperature. In a further embodiment of the present invention the method is conducted at minimum 20°C. In a further embodiment of the present invention the method is conducted at 10-45°C.

In another embodiment of the present invention formula (l):co-precipitate (M ⁺ and X ) is in an about 1 :1 - 5:1 molar ratio, such as, 1 :0.01 - 1 :100 or 1 :0.1 - 1 :10, preferably 1 :1 ratio to reduce the amount of used formula (I) per one desalination cycle. Repeated cycles, or re-cycling, will usually be performed in order to achieve the target salinity.

In an embodiment of the present invention the method is performed on an industrial scale.

An aspect of the present invention relates to an amine selected from the group consisting of:

In an embodiment of the present invention one or more of the amines are for use in a method of desalination according to the present invention. An aspect of the present invention relates to a method of synthesizing an insoluble solid-state polymer based on the formula (I) comprising the step of: wherein the synthesis of polymer-supported diamine is performed by using a general

polymerization procedure wherein the diamine, styrene, 1 ,4-divinylbenzene (0-10 mol%) and radical initiator (0-10 mol%) is mixed in water or organic solvent, or water-organic solvents mixture, and stirred at elevated temperature for extended time, and wherein the obtained polymer is washed with relevant organic solvent and water to remove unreacted residue and smaller molecular weight polymers to afford desired diamine-functionalized polymers. or

wherein the synthesis of alkyl chain modified polyethylene imine is performed by reacting PEI (polyethyleneimine) with an alkyl halide in water or organic solvent, or water-organic solvents mixture, and stirred at elevated temperature for extended time, and wherein the obtained polymer is washed with relevant organic solvent and water to removed unreacted residue and smaller molecular weight polymers to afford desired diamine-functionalized polymers. An aspect of the present invention relates to the solid-state polymer produced from a method of the present invention.

An aspect of the present invention relates to a method of CO2 scrubbing comprising the steps; i) contacting an amine of formula (I) with mixture A to generate an aqueous mixture comprising amine and salt (mixture B), ii) contacting mixture B with CO2 for a sufficient time period to coprecipitate with the amine of formula (I), ⁺M _a, and Xb to generate a precipitate (Z), and iii) isolate the precipitate (Z) comprising CO2 to obtain an aqueous mixture C of lower salinity than aqueous mixture (A), wherein the amine formula (I) is defined by:

Formula (I) wherein, Ri , R2 and R3 is selected independently from H, Me, Et, n-Pr, i-Pr, n-Bu, i-Bu, t-Bu, Ph, Benzyl, and Aryl, X is selected from C=0, C=NH, C=S, CHF, CFI2 and CF2, R4 and Rs is selected independently from CFI3, FI and F, n is an integer from 1-4 included, m is an integer from 3-18 included, and wherein ⁺M _a is a cation ⁺M with a indicating the number of cations in the salt, and Xb is an anion X with b indicating the number of anions in the salt.

An aspect of the present invention relates to a method for CO2 complexation, CC>2-capture and/or CO2 sequestration comprising the steps; i) contacting an amine of formula (I) with mixture A to generate an aqueous mixture comprising amine and salt (mixture B), ii) contacting mixture B with CO2 for a sufficient time period to co-precipitate with the amine of formula (I), ⁺M _a, and Xb to generate a precipitate (Z), and iii) isolate the precipitate (Z) comprising CCte to obtain an aqueous mixture C of lower salinity than aqueous mixture (A), wherein the amine formula (I) is defined by:

Formula (I) wherein, Ri, F¾ and F¾ is selected independently from H, Me, Et, n-Pr, i-Pr, n-Bu, i-Bu, t-Bu, Ph, Benzyl, and Aryl, X is selected from C=0, C=NH, C=S, CHF, CH2 and CF2, R4 and R5 is selected independently from CH3, H and F, n is an integer from 1-4 included, m is an integer from 3-18 included, and wherein ⁺M _a is a cation ⁺M with a indicating the number of cations in the salt, and Xb is an anion X with b indicating the number of anions in the salt.

In an embodiment of the present invention the residual amine from mixture C is further reduced by applying ion exchange resin or microfiltration. The further reduction of the residual amine from mixture C can be by applying a filter, by attachment of the diamine to a surface or a combination of both applying a filter and attachment of the diamine to a surface to separate the diamine, either bound or unbound to the salt, from the aqueous solution. The salt can be released from the diamine by reversing the method, or the method of the present invention can be repeated to reach the required salinity level. Additional desalination methods can be included as additional steps. The methods of the present invention can also be applied as additional desalination method steps that can improve known desalination technologies.

In another embodiment of the present invention the residual amine from mixture C is further reduced by applying low temperature to increase precipitation rate, or to induce phase separation.

In another embodiment of the present invention the mixture C is diluted with fresh water with low salinity level, to provide maximum volume of drinkable water (potable water) using desalinated mixture C.

In an embodiment of the present invention the salinity level of mixture C reaches drinkable water by applying subsequent desalination.

In another embodiment of the present invention the subsequent desalination comprises the repeating the steps of i) contacting an amine of formula (I) with mixture A to generate an aqueous mixture comprising amine and salt (mixture B), ii) contacting mixture B with CO2 for a sufficient time period to co-precipitate with the amine of formula (I), ⁺M _a, and Xb to generate a precipitate (Z), and iii) isolate the precipitate (Z) to obtain an aqueous mixture C of lower salinity than aqueous mixture A until the required level of salinity is achieved. In another embodiment of the present invention the precipitate Z is dissolved in organic solvent(s) to precipitate salts upon heating the system using mild heat source (30 - 80°C) or waste heat to remove the CO2. Thus, the salt can be released from the diamine complex while the diamine is solubilized in organic solvent (s).

In an embodiment of the present invention the solvent is water. In an even further embodiment the water is seawater.

In another embodiment of the present invention and after the precipitation of salts, the diamine formula (I) is recovered by evaporating the used organic solvents.

In another embodiment of the present invention and the mild heat (30 - 80°C) is from sunlight

In another embodiment of the present invention precipitate Z is formed applying ambient or low temperature in a range of 0 - 20°C to increase precipitation rate, and/or to induce phase separation.

In another embodiment of the present invention the method of the present invention is further comprising one or more steps of membrane distillation desalination and/or reverse osmosis desalination.

In an embodiment of the present invention the further one or more steps are included in before or after contacting of the amine of formula (I) with mixture A. This can for example be a step of filtering to prepare the solution for desalination.

An aspect of the present invention relates to a kit for desalination comprising a compound of formula (I).

In another embodiment of the present invention the kit of the present invention is further comprising a compound with a purpose of colour indication upon desalination. In another embodiment of the present invention the kit of the present invention is further comprising one or more disinfectants. In another embodiment of the present invention the kit of the present invention is further comprising iodine. In another embodiment of the present invention the kit of the present invention is further comprising sugar and/or other carbohydrates.

In a further embodiment of the present invention the kit is an emergency kit. In a further embodiment of the present invention the kit is portable. DETAILED DESCRIPTION

The present inventors have invented an energy efficient and fast method to desalinate saline aqueous solutions by the surprising finding that a C0 ₂-responsive self-assembly process, which are previously only know to happen in non-aqueous solutions, can induce co-precipitation of solubilized ions (salts) and other substances in aqueous solutions. The main component of said desalination process is the amine structures described herein. During the energy-efficient desalination process, the organic CCh-responsive material captures CO ₂, as well as the solubilized ions (salts) in the aqueous solution.

The water desalination processes therefore separate dissolved salts (solubilized ions) and other minerals from water.

After the salts have been co-precipitated with CO ₂ and the organic CC -responsive material, the desalinated aqueous solution (e.g. water) can be isolated in one fraction, and the organic CO ₂- responsive materials of the present invention can be isolated in a second fraction. This second fraction comprising the organic CC -responsive material complexed with the salts and C02 can be re-activated by simply reducing the pressure or using mild heat. Upon such re-activation, the amine complex releases C02 as well as the captured salts, such as NaCI. The re-activation of the organic C0 ₂-responsive material completes the catalytic cycle of the desalination process, where after the cycle can be repeated by reacting the organic CCh-responsive material with a second or further batch of an aqueous solution comprising salts.

The process is performed by introducing CO ₂ or CO ₂ gas feed or stream to the solution of the CO ₂- responsive material and aqueous polar minerals to induce the spontaneous precipitation with the polar minerals, such as NaCI. The CO ₂ needed to catalyse the reaction can be taken from atmospheric air, e.g. by adding atmospheric air to the reaction, or by purifying CO ₂ from the atmospheric air. The CO ₂ can furthermore be added as the breath, i.e. exhaust air, of a human, or from any other CO ₂ source in either pure or diluted form. The CCh-responsive material with the captured salts and CO ₂ can then be separated from the aqueous solution by conventional separation methods, e.g. by gravimetric separation, centrifugation, decantation, by applying filters or immobilising the CC -responsive material. The filtration can be micro-, ultra- or nanofiltration, most preferable ultrafiltration.

The isolated CCh-responsive material can be regenerated by applying mild heat to release the CO ₂ as well as the polar minerals from the diamines. The salts can be collected and potentially purified further into commercial quality. As an extra feature, the released CO ₂ can be also collected, and either be stored, sold or re-used in the next and consecutive process rounds. Accordingly, the present inventors have surprisingly found that the use of a particular diamine, the organic C02-responsive material, can provide desalination using CO ₂, under ambient conditions, i.e. at room temperature and under atmospheric pressure. The presented invention is operable in any type of saline feedwater, such as but not limited to seawater, where the saline feedwater can undergo a salinity reduction process to achieve a high desalination rate, or high response rate, to realize an ideal desalination , implying that the reduction of salinity will be performed under kinetically favoured pathways. Also, the recyclability of the materials will eventually reduce the environmental impact of the technology and provide a sustainable and environmentally feasible desalination methodology which at the same time is economically beneficial.

In its broadest aspect, the present invention relates to a method for reduction of the amount of solubilized ions (salts) in an aqueous solution containing such solubilized ions (salts). One embodiment of the broadest aspect is a method for desalination or reduction of salinity of saline water to produce potable water, salinity-reduced water, e.g. for industrial applications or desalination or reduction of salinity of waste-water. The solution to the problem underlying the invention is achieved by providing a specific molecular structure containing a CC -responsive unit (the diamines of the present invention) with aliphatic linear alkyl chains (hydrophobic fatty acid-like structures) which can simultaneously induce self-aggregation in the presence of salts, such as NaCI, in aqueous solution, such as in saline water.

The desalination process is induced by using CO ₂ such as pure CO ₂ or concentrated CO ₂ gas and an appropriate CC -responsive organic molecule which can generate polymeric aggregates incorporating ions, such as Na and Cl ions (i.e. Na ⁺ and Cl , sometimes written as ⁺Na and Cl), where these aggregates with a high-molecular weight will precipitate from the aqueous phase, thereby generating desalinated water.

Thus, one aspect of the present invention relates to a method for reduction of salts (solubilized ions) in an aqueous solution comprising such salts of formula ⁺M _a Xb (mixture A), comprising the steps; contacting an amine of formula (I) with mixture A to generate an aqueous mixture comprising amine and salts (mixture B), ii) contacting mixture B with CO ₂ for a sufficient time period to co-precipitate with the amine of formula (I), ⁺M _a, and Xb to generate a precipitate (Z), and iii) isolate the precipitate (Z) to obtain an aqueous mixture C of lower salinity than aqueous mixture A, optionally with a repeat or re-cycling of steps (I) to (III), wherein the amine formula (I) is defined by:

Formula (I) wherein, Ri , F¾ and F¾ are selected independently from H, Me, Et, n-Pr, i-Pr, n-Bu, i-Bu, t-Bu, Ph, Benzyl, and Aryl; X is selected from C=0, C=NH, C=S, CHF, CH2 and CF2; R4 and R5 is selected independently from CH3, H and F; n is an integer from 1-4 included; m is an integer from 3-18 included; and wherein ⁺M _a is a cation ⁺M with a indicating the number of cations in the salts; and Xb is an anion X with b indicating the number of anions in the salts.

⁺M _a can also be shown as M ^a+, and Xb as X ^b throughout this disclosure.

Several different salts of formula ⁺M _a Xb can be present in the solution. This is often the case for solutions that are not the product of artificial processes. One example can be seawater. In this case are several salts (i.e. the soluble ions of the salts) present, and these can co-precipitate in the methods of the present invention.

One embodiment of the present invention relates to a method for desalination of an aqueous solution comprising a salt of formula ⁺Na ΌI (mixture A), comprising the steps; i) contacting an amine of formula (I) with mixture A to generate an aqueous mixture comprising amine and salt (mixture B), ii) contacting mixture B with CO2 for a sufficient time period to co-precipitate with the amine of formula (I), ⁺Na, and Cl to generate a precipitate (Z), and iii) isolate the precipitate (Z) to obtain an aqueous mixture C of lower salinity than aqueous mixture A, wherein the amine formula (I) is defined by:

Formula (I) wherein, Ri and F¾ are Me, F¾ is H, X is CH2, R ₄ and R5 are H, n is 3, and m is an integer from 7-15 included.

In an embodiment of the present invention the method is performed on an industrial scale. In a second embodiment of the invention the method is performed in single user scale.

Salt

A salt is an ionic compound that can be formed by the neutralization reaction of an acid and a base. Salts are composed of related numbers of cations (positively charged ions) and anions (negative ions) so that the product is electrically neutral (without a net charge). These component ions can be inorganic, such as chloride (Cl ), or organic, such as acetate (CH3CO ² ); and can be monatomic, such as fluoride (F ), or polyatomic, such as sulphate (SO ₄ ² ).

The water desalination processes of the present invention therefore separate dissolved salts which are solubilized ions from water. Additionally, minerals can also be separated from the water during the process. In an embodiment of the present invention is ⁺M is selected from the group consisting of a monovalent metal cation, a divalent metal cation, a trivalent metal cation, and an ammonium ion.

In a further embodiment of the present invention ⁺M selected from the group consisting of an ammonium ion, a sulfonium ion, and a phosphonium ion. In another embodiment of the present invention is Xb a monovalent halogen is selected from the group consisting of F , Cl , Br , I , CN (cyanide), OCN (cyanate), NO3 (nitrate), NO2 (nitrite), HS0 ⁴ (hydrogen sulfate), H2PO4

(dihydrogen phosphate). CIO3 (chlorate), CIC (perchlorate), OCI (hypochlorite), acetate, SCN (thiocyanate), OHN (hydroxide), MnC (permanganate) and divalent anions selected from the group consisting of SO4 ² (sulfate), S2O3 ² (thiosulfate), SO3 ² (sulfite), HPO4 ² (hydrogen phosphate), CrC ² (chromate), Cr20 ² (dichromate), and trivalent anion PO4 ³ (phosphate).. In a further embodiment of the present invention is Xb phosphate. In another embodiment of the present invention is Xb carbonate. In an embodiment of the present invention is Xb sulfate. In a further embodiment of the present invention is Xb bicarbonate. In an embodiment of the present invention is the salt selected from the group consisting of NaCI, KCI, LiCI, LiBr, Lil, LiF, NaF, NaBr, Nal, KF, KCI, KBr, Kl, Na ₂S0 ₄, K2SO4, MgS0 ₄, CaF ₂, CaCI ₂, CaBr ₂, Cal ₂, CaS0 ₄. In another embodiment of the present invention the salt is selected from the group consisting of sodium, potassium, calcium, magnesium, chloride, sulphate, bicarbonate, carbonate and nitrate.

Salt is present in vast quantities in seawater, where it is the main mineral constituent. The open ocean has about 35 grams of solids per litre, a salinity of 3.5%.

In another embodiment of the present invention is the salt NaCI.

Diamine

The present invention provides a simple and rapid method of producing salinity-reduced water. Various organic C0 ₂-responsive materials can be applied in the system, more specifically, materials which interact with C0 ₂ under ambient conditions i.e. room temperature and under atmospheric pressure.

Particularly, organic materials provide good kinetics in terms of C0 ₂ complexation, therefore the operation time for the desalination can be significantly reduced compared to existing desalination technologies. In addition, the obtained C0 ₂-diamine complexes possess thermodynamic stability which means that the technology described herein allows ample time to process the desalinated aqueous solution, without significant backward reaction (decomplexation processes), where such backward reaction will result in re-salination of the aqueous solution.

Diamines have been used in many different fields of science and industry. Any type of nucleophilic substances can be used for activating or complexing C0 ₂, for example, primary, secondary, tertiary amines, ionic liquids, phosphorous-based nucleophiles. However, as the organic C0 ₂-responsive material needs to be produced in industrial scale, it is important that the synthetic procedure allow simple to access the nucleophilic substrate for complexing C0 ₂. Therefore, the present invention focuses on diamine-based the organic C0 ₂-responsive materials which are easily produced.

Moreover, due to the flexible synthetic routes toward diamines, various diamines can quickly be assembled and tested for the applicability in desalination of aqueous solutions. The structure of the diamines and the aliphatic units are critical to retain the optimum performance of desalination, high reaction rate and high desalination capacity. Various diamines with different chemical backbones render a variety of chores for alternative applications, including C0 ₂ capture and sequestration, heavy metal capture, pollutant removal, C0 ₂-functionalization, and catalytic application in C0 ₂ utilization reaction to synthesize valuable molecules such as, polycarbonate, urea, carbonate, salicylic acids from C0 ₂ as a chemical feedstock. Thus, the present invention relates to methods of preparation of diamines and the use of the same, in particular for desalination, more specifically, salinity reduction and metal capture and separation using CO2 as a mediator. All the methods make use of a diamines and CO2, where the diamines have at least one nucleophilic nitrogen-atom containing CC -responsive molecule, which can participate in CO2 complexation and co-precipitation with salts upon changing solubility in aqueous or organic solvent solution, preferably seawater, brackish water, sweet water well water, surface water (from rivers or streams), wastewater, industrial feed water, industrial process water, waste water and brine with metal ions, organic and inorganic ions including minerals and salts, and draw solution in FO (Forward Osmosis).

A draw solution is a high concentrated salt solution used in Forward Osmosis to draw water molecules through a membrane which retains larger molecules like salts and/or organics.

The desalination can take place via a CO2 introduction step to the solution or dispersion of diamines to the liquid phase.

Many of the tested substances in the examples section of the present disclosure show desalination capacity to some extend, and usable desaliantion capacity was obtained with following structures:

Further usable diamines are listed in Table 1 . In one embodiment of the present invention the diamine for use in the method of the present invention is selected from the group of diamine structures shown above and in Table 1.

In one embodiment of the present invention is the diamine of formula C12:

Formula C12.

These C0 ₂-responsive molecules all shows a salinity reduction over 30% (below 10 g NaCI/L at the end point salinity, i.e. 2.9 - 0.6 g/L). This finding indicate the importance of two cirteria: 1 ) the presence of a diamine with either 2 - 4 carbon atoms between the individual amine moieties, and 2) the appropriate length of the alkylchain attached to promote precipitation of the diamine- CC>2/NaCI complex.

The organic structure of the CC>2-responsive unit (the diamines) is preferably selected from any diamines, amino alcohols, primary amines, secondary amines, tertiary amines, and related heteroatom-containing functional groups that can chelate CO2 or form ion-ion complex with CO2.

In a preferred embodiment of the present invention is the diamine defined as:

Formula (I)

The alkyl chain group is advantageously selected from the group of molecules including aliphatic carbon chains thereof, preferably selected from hexyl-, heptyl- and higher molecular weight organic linear or branched molecules.

As preferred measure, the organic material for CO2 complexation is preferably diamine with two- four carbon between two amine atoms, either ethylene diamine or propylene diamine with and without any substituents on the nitrogen atoms.

The aliphatic alkyl chains facilitate aggregation and precipitation, and the aliphatic chains are introduced synthetically via a one-step procedure, in particular with diamines as nucleophilic reagents and alkyl halides as electrophilic reagents.

In another embodiment of the present invention m equals 13. In a further embodiment of the present invention m equals 14. In an embodiment of the present invention m equals 15. In another embodiment of the present invention m equals 16. In a further embodiment of the present invention m equals 17. In an embodiment of the present invention m equals 18.

In a further embodiment of the present invention formula (I) is any of the compounds listed in figure 1 and/or Table 1.

In a further embodiment of the present invention Ri is H. In another embodiment of the present invention Ri is Me. In an embodiment of the present invention is Ri Et. In another embodiment of the present invention Ri is n-Pr. In a further embodiment of the present invention Ri is i-Pr. In an embodiment of the present invention Ri is n-Bu. In a further embodiment of the present invention Ri is i-Bu. In an embodiment of the present invention Ri is t-Bu. In another embodiment of the present invention Ri is Ph. In a further embodiment of the present invention Ri is H Benzyl. In an embodiment of the present invention Ri is Aryl. In a further embodiment of the present invention R _å is H. In an embodiment of the present invention R _å is Me. In a further embodiment of the present invention R ₂ is Et. In another embodiment of the present invention R ₂ is n-Pr. In an embodiment of the present invention R ₂ is i-Pr. In a further embodiment of the present invention R ₂ is n-Bu. In another embodiment of the present invention R ₂ is i-Bu. In an embodiment of the present invention R ₂ is t-Bu. In a further embodiment of the present invention R ₂ is Ph. In an embodiment of the present invention R ₂ is Benzyl. In another embodiment of the present invention R ₂ is Aryl. In a further embodiment of the present invention R3 is H. In another embodiment of the present invention R3 is H. In a further embodiment of the present invention R3 is Me. In an embodiment of the present invention R3 is Et. In an embodiment of the present invention R3 is n-Pr. In a further embodiment of the present invention R3 is i-Pr. In another embodiment of the present invention R3 is n-Bu. In a further embodiment of the present invention R3 is t-Bu. In an embodiment of the present invention R3 is Ph. In an embodiment of the present invention R3 is Benzyl. In another embodiment of the present invention R3 is Aryl. In an embodiment of the present invention X is C=0. In a further embodiment of the present invention X is C=NH. In a further embodiment of the present invention X is C=S. In an embodiment of the present invention X is CHF. In another embodiment of the present invention X is CH ₂. In an embodiment of the present invention X is CF ₂. In a further embodiment of the present invention R4 is CH3. In an embodiment of the present invention R ₄ is H. In a further embodiment of the present invention R ₄ is F. In another embodiment of the present invention Rs is CF . In a further embodiment of the present invention Rs is H. In a further embodiment of the present invention Rs is F.

An aspect of the present invention relates to an amine selected from the group consisting of:

In an embodiment of the present invention one or more of the amines are for use in a method of desalination according to the present invention.

Aqueous solution

An aqueous solution is a solution in which the solvent is water. It is mostly shown in chemical equations by appending (aq) to the relevant chemical formula. For example, a solution of table salt, or sodium chloride (NaCI), in water would be represented as Na ⁺(aq) + Cl (aq). The word aqueous means pertaining to, related to, similar to, or dissolved in, water.

Seawater is water from a sea or ocean. On average, seawater in the world's oceans has a salinity of 35 g/L. A salinity of 35 (35 g/L) means that every kilogram of seawater has 35 grams of dissolved salts (predominantly sodium (Na ⁺) and chloride (Cl ) ions).

Brackish water is water that has more salt than freshwater, but not as much as seawater. It may result from mixing of seawater with fresh water, as in estuaries, or it may occur in brackish fossil aquifers. The word comes from the Middle Dutch root "brak".

Technically, brackish water contains between 0.5 and 30 grams of salt per litre. Thus, brackish covers a range of salinity regimes and is not considered a precisely defined condition. It is characteristic of many brackish surface waters that their salinity can vary considerably over space or time. Brackish well water can also be found in arid regions where over exploitation over decades has turned the groundwater too saline for drinking purposes., and some fresh-water wells have turned salty and become brackish.

Brine is a high-concentration solution of salt (usually sodium chloride) in water. In different contexts, brine may refer to salt solutions ranging from about 35 g/L (a typical concentration of seawater) on the lower end and up to about 260 g/L (a typical saturated solution after food processing). Thus, brine can be an aqueous solution containing salt in the concentration from about 35 g/L to about 260 g/L. Brine is a by-product of many industrial processes, such as desalination for human consumption, irrigation, power plant cooling towers, produced water from oil and natural gas extraction, acid mine or acid rock drainage, reverse osmosis reject, chlor-alkali wastewater treatment, pulp and paper mill effluent, and waste streams from food and beverage processing.

Lower levels of salt concentration in water are called by different names: fresh water, brackish water, and saline water.

Thus, in a further embodiment of the present invention the aqueous solution is selected from the group consisting of seawater, brackish water, well water, surface water (from rivers and streams), wastewater, industrial feed water, industrial process water, saline water, brine, salt-enriched water, and draw solutions in FO (Forward Osmosis).

A draw solution is a high concentrated salt solution used in Forward Osmosis to draw water molecules through a membrane which retains larger molecules like salts and/or organics.

In an embodiment of the present invention the aqueous solution is seawater. In a further embodiment of the present invention the aqueous solution is wastewater. In a further embodiment of the present invention the aqueous solution is brine. In a further embodiment of the present invention the aqueous solution is industrial feed water. In a further embodiment of the present invention the aqueous solution is industrial process water.

In an embodiment of the present invention the aqueous solution is seawater. In another embodiment of the present invention the aqueous solution is brackish water. In a further embodiment of the present invention the aqueous solution is wastewater. In a further embodiment of the present invention the aqueous solution is brine. In a further embodiment of the present invention the aqueous solution is industrial feed water. In a further embodiment of the present invention the aqueous solution is industrial process water. In another embodiment of the present invention the aqueous solution is saline water. In another embodiment of the present invention the aqueous solution is brine.

In another embodiment of the present invention the salt concentration of mixture A is 0.1 - 400 g/L. In a further embodiment of the present invention the salt concentration of mixture A is 30 - 400 g/L. In yet another embodiment of the present invention the salt concentration of mixture A is 5 - 50 g/L. In another embodiment of the present invention the salt concentration of mixture A is 10 - 50 g/L. In an embodiment of the present invention the salt concentration of mixture A is 100 - 400 g/L. In a further embodiment of the present invention the salt concentration of mixture A is 20 - 400 g/L. In another embodiment of the present invention the salt concentration of mixture A is 150 - 400 g/L.

In a further embodiment of the present invention the salt concentration of mixture C is less than 0.5 g/L (fresh water. In an embodiment of the present invention the salt concentration of mixture C is above 0.5 g/L but less than 30 g/L (brackish water). In a further embodiment of the present invention the salt concentration of mixture C is less than 0.5 g/L. In another embodiment of the present invention the salt concentration of mixture C is less than 5 g/L. In a further embodiment of the present invention the salt concentration of mixture C is less than 10 g/L. In yet another embodiment of the present invention the salt concentration of mixture C is less than 25 g/L. In a further embodiment of the present invention the salt concentration of mixture C is less than 50 g/L. In a further embodiment of the present invention the salt concentration of mixture C is less than 75 g/L. In a further embodiment of the present invention the salt concentration of mixture C is less than 100 g/L.

Steps in the methods of the present invention

The methods of the present invention can be adapted depending on the means of the method. Thus, in a further embodiment of the present invention the aqueous solution (mixture A) furthermore comprises a compound selected from the group consisting of organic amines (formula (I)), ammonium salt of formula (I), ammonium carbamate of formula (I), ammonium carbonate salt of formula (I), and ammonium bicarbonate salt of formula (I).

In another embodiment of the present invention the salt concentration of mixture C is no more than 15 % of the salt concentration of mixture A. The salt concentration of mixture C can also be no more than 25 % of the salt concentration of mixture A. The salt concentration of mixture C can also be no more than 35 % of the salt concentration of mixture A. The salt concentration of mixture C can also be no more than 5 % of the salt concentration of mixture A. The salt concentration of mixture C can also be no more than 50 % of the salt concentration of mixture A. In another embodiment of the present invention the salt concentration of mixture C is no more than 0.5 g/L of total dissolved salt. In a further embodiment of the present invention the salt concentration of mixture C is less than 5 g/L of salt).

In an embodiment of the present invention mixture C comprises water, salts, including NaCI and/or other remaining ionic salts and polar molecules, amine based on formula (I), and related ammonium salts based on formula (I).

In a further embodiment of the present invention the contacting step described in step i) is done by mixing, shaking, adding, slurring, or injecting the diamine based on formula (I) into mixture A. In a preferred embodiment of the present invention the chosen contacting step is the contacting step that allows for the fastest reaction under the given reaction conditions to afford highest degree of salinity reduction of ion capture.

In another embodiment of the present invention the amine and diamine in mixture A is soluble, polymeric, immobilized, insoluble, homo- or heterogenous.

In an embodiment of the present invention the residual amine from mixture C is further reduced by applying ion exchange resin or filtration, such as ultra-, nano- or microfiltration. The further reduction can be by applying a filter, or attachment/adsorption of the amine to a surface or a combination of applying a filter and attachment/adsorption of the amine to a surface to separate the diamine from the salt. The salt can be released from the diamine by reversing the method, or the method of the present invention can be repeated to reach the required salinity level. Additional desalination methods can be included as next steps. The methods of the present invention can also be applied as additional desalination method steps that can improve known desalination technologies. Further reduction can for example be by applying a filter or attachment/adsorption to a surface or both to separate the diamine from the salt.

In another embodiment of the present invention the residual amine from mixture C is further reduced by applying low temperature to increase precipitation rate, or to induce phase separation.

In another embodiment of the present invention the mixture C is diluted with fresh water with low salinity level, to provide maximum volume of desalinated water drinkable water using desalinated mixture C. Mixture C can also be diluted with water with a lower salinity level than mixture C to obtain the salinity that is required for the intended purpose.

In an embodiment of the present invention the salinity level of mixture C reaches drinkable water quality, i.e. salinity of below 0.6 g/L. In a further embodiment of the present invention the salinity level of mixture C reaches a salinity level below 0.6 g/L. The salinity level is preferentially measured at 20 degrees C. In another embodiment of the present invention the subsequent steps comprise steps i) to iii) of claim 1.

The desalination process can be conducted by bubbling CO2 or introducing CO2 gas feed (or stream) to the solution of the said material in saline water to induce spontaneous precipitation with salts.

Therefore, this invention is directed to a process of desalination using CC -responsive materials, which have switchable chemical properties towards CO2 and salts (mainly NaCI), and physical properties before and after complexing with CO2. This switchable property is the key to the successful CC -meidated desalination process since the additional chemical potential or energy sources are driven by self-assembly of CCh-reponsive molecules. Accordingly, the reaction needs to be fed by a sufficient amount of CO2 during the reaction. The needed CO2 is from any sources. Around 9 L of CO2 at 1 bar pressure is needed for 0.1 L diamine.

Thus, in another embodiment of the present invention the CO2 is gaseous. In an embodiment of the present invention the CO2 is naturally occurring CO2 extracted from the surrounding air preferably through systems which ensures that atmospheric air, containing CO2, is pumped into mixture A. In a further embodiment of the present invention the CO2 is from exhaled breath from a human. In a further embodiment of the present invention the CO2 can be provided from compressed CO2 cylinders. Other sources of CO2 include flue gas, combustion gas feed, geological CO2 sources (e.g. volcano), chemical CO2 production (e.g. from CaC03 or NaHCOs).

In a further embodiment of the present invention the CO2 concentration is from 4 ppm to 100 % pure. In a further embodiment of the present invention the CO2 concentration is 2000 ppm to 10000 ppm. In another embodiment of the present invention the CO2 concentration is 20 ppm to 10000 ppm. In a further embodiment of the present invention the CO2 concentration is 200 ppm to 10000 ppm. In yet another embodiment of the present invention the CO2 concentration is 200 ppm to 1000 ppm. In a further embodiment of the present invention the CO2 concentration is 500 ppm to 10000 ppm. In another embodiment of the present invention the CO2 concentration is 25 ppm to 100 ppm.

In another embodiment of the present invention the sufficient time period in step (ii) is 5 seconds to 15 minutes. The time period can also be 2 minutes to 30 minutes. The time period can also be 10 minutes to 90 minutes. The time period can also be 1 minute to 10 minutes. The time period can also be 2 minutes to 30 minutes. The time period can also be 30 seconds to 60 minutes. Though the interaction between diamines and CO2 preferably induced by introducing carbon dioxide as a gaseous form, it is also possible to form diamine-CC adduct in a different way by using solid CO2 (dry ice) or under supercritical CO2 conditions.

The solid precipitate Z can be separated by gravimetric separation, centrifuge, decantation and other conventional separation methods. Thus, in another embodiment of the present invention the precipitate is separated by filtration, gravimetrical separation, centrifugation or decantation. The filtration can be micro-, ultra- or nanofiltration, most preferable ultrafiltration.

In a further embodiment of the present invention the precipitate Z comprises organic diamines based on formula (I) comprising carbon dioxide and salts, which originated from mixture A. In another embodiment of the present invention the precipitate Z is a mixture of the diamine, the diamine-C0 ₂ adducts, the diamine-salt complex, diamine-based ammonium salts of bicarbonate, carbonated, and sodium chloride.

In another embodiment of the present invention formula (l):co-precipitate (M ⁺ and X ) is in an about 1 : 1 - 5:1 molar ratio, such as, 1 :0.01 - 1 : 100 or 1 :0.1 - 1 : 10, preferably 1 :1 ratio to reduce the amount of used formula (I) per one desalination cycle. Repeated cycles, or re-cycling, will usually be performed in order to achieve the target salinity.

The methods of the present invention are normally performed in ambient temperature, that is the air temperature of the immediate environment. However, it can be relevant to perform the methods at other temperatures by cooling or heating, in order to optimize the output. One way of doing this is to prepare the mixture A to be in contact with higher temperature sources (sunlight, body heat, or heated matters generated by electricity, solar heat fuel) to increase the temperature, and therefore add energy and heat to the reaction.

Thus, in one embodiment of the present invention the method is conducted at room temperature, i.e. 20°C. In a further embodiment of the present invention the method is conducted at minimum 20°C. In a further embodiment of the present invention the method is conducted at 10-45°C. The method can also be performed at ambient temperature.

In another embodiment of the present invention the precipitate Z is dissolved in organic solvent(s) to precipitate salts out of the used organic solvents upon heating the system using mild heat source or waste heat to remove CO2. Thus, the salt can be released from the diamine complex while the diamine is solubilized in solvent (s). The solvent can be an organic solvent. The solvent can also be water. In an embodiment of the present invention the organic solvent and water is the medium and the mild heat is from sunlight.

In another embodiment of the present invention after precipitation of salts, the diamine formula (I) is recovered by evaporating the used organic solvents.

In another embodiment of the present invention precipitate Z is formed applying ambient or low temperature in a range of 0 - 20 °C to increase precipitation rate, and/or to induce phase separation.

In another embodiment of the present invention the method of the present invention is further comprising one or more steps of membrane distillation desalination and/or reverse osmosis and/or forward osmosis desalination.

In an embodiment of the present invention the further one or more steps are included in before or after contacting of the amine of formula (I) with mixture A.

Further methods

The present invention furthermore relates to additional methods that exploit the diamines ability to interact with salt and carbon dioxide. One example could be to use solid state polymers for the methods of the present invention. These can lead to a reduced diamine leakage.

Thus, an aspect of the present invention relates to a method of synthesizing an insoluble solid- state polymer based on the formula (I) comprising the step of: wherein the synthesis of polymer-supported diamine is performed by using a general

polymerization procedure wherein the diamine, which can be any of the diamines mentioned herein, styrene, 1 ,4-divinyl benzene (0-10 mol%) and radical initiator (0-10 mol%) is mixed in water or organic solvent, or water-organic solvents mixture, and stirred at elevated temperature for extended time, and wherein the obtained polymer is washed with relevant organic solvent and water to removed unreacted residue and smaller molecular weight polymers to afford desired diamine-functionalized polymers, or wherein the synthesis of alkylchain modified polyethylene imine is performed by reacting PEI (polyethyleneimine) with an alkyl halide in water or organic solvent, or water-organic solvents mixture, and stirred at elevated temperature for extended time, and wherein the obtained polymer is washed with relevant organic solvent and water to removed unreacted residue and smaller molecular weight polymers to afford desired diamine-functionalized polymers. The diamine can be any of the diamines mentioned herein. For example, when the alkylchain is C16 will the product be PEI-C16.

An aspect of the present invention relates to the solid-state polymer produced from a method of the present invention, which can have any C-length mentioned herein.

Further applications of the diamines of the present invention relates to the capture of carbon dioxide. Carbon dioxide is a well-known greenhouse gas, which is produced in high amounts in industry, by cars etc.

Thus, an aspect of the present invention relates to a method of CO2 scrubbing comprising the steps; i) contacting an amine of formula (I) with mixture A to generate an aqueous mixture comprising amine and salt (mixture B), ii) contacting mixture B with CO2 for a sufficient time period to co-precipitate with the amine of formula (I), ⁺M _a, and Xb to generate a precipitate (Z), and iii) isolate the precipitate (Z) comprising CO2 to obtain an aqueous mixture C of lower salinity than aqueous mixture (A), wherein the amine formula (I) is defined by:

Formula (I) wherein, R1 , R2 and R3 is selected independently from H, Me, Et, n-Pr, i-Pr, n-Bu, i-Bu, t-Bu, Ph, Benzyl, and Aryl, X is selected from C=0, C=NH, C=S, CHF, CH2 and CF2, R ₄ and Rs is selected independently from CH3, FI and F, n is an integer from 1-4 included, m is an integer from 3-18 included, and wherein ⁺M _a is a cation ⁺M with a indicating the number of cations in the salt, and Xb is an anion X with b indicating the number of anions in the salt.

A further aspect of the present invention relates to a method for CO2 complexation, CC>2-capture and/or CO2 sequestration comprising the steps; i) contacting an amine of formula (I) with mixture A to generate an aqueous mixture comprising amine and salt (mixture B), ii) contacting mixture B with CO2 for a sufficient time period to co-precipitate with the amine of formula (I), ⁺M _a, and Xb to generate a precipitate (Z), and iii) isolate the precipitate (Z) comprising CCte to obtain an aqueous mixture C of lower salinity than aqueous mixture (A), wherein the amine formula (I) is defined by:

Formula (I) wherein, Ri , F¾ and F¾ is selected independently from H, Me, Et, n-Pr, i-Pr, n-Bu, i-Bu, t-Bu, Ph, Benzyl, and Aryl, X is selected from C=0, C=NH, C=S, CHF, CH2 and CF2, R4 and R5 is selected independently from CH3, H and F, n is an integer from 1-4 included, m is an integer from 3-18 included, and wherein ⁺M _a is a cation ⁺M with a indicating the number of cations in the salt, and Xb is an anion X with b indicating the number of anions in the salt.

Adsorption or desorption of C02 from a solution of monoethanolamine in water requires 80-85 kJ/mol of energy. Flowever, in the absence of water the required heat is reduced. As an example, the heat of adsorption and desorption of a diamine appended MOF was reduced to 20-25 kJ/mol (chem. Rev. 2012, 1 12, 724-781 , Nature 2015, 519, 303, J. Am. Chem. Soc. 2017, 139, 13541 ). This means that the energy required for C02 cycling in the absence of water will be significantly lower, which in turn means that our recycling processes are more energy efficient than conventional desalination processes (performed in water media).

PEI polymers are easy to access and inexpensive. The structure of PEI is 1 ,2-ethylene diamine, a chemically identical structure to the monomeric diamines. In the current invention, a water-soluble PEI has been modified by a one-step alkylation reaction. This produces a highly stable polymeric diamine derivative which is not water soluble but is still able to uptake CO2 and, therefore, desalinate water. Since the polymer is not water-soluble, after desalination is complete it can be easily removed from the water by filtration or decanting, and thereby regenerated and/or recycled. Diamines can be immobilized onto solid state materials, including metal-organic frameworks (Basolite, ZIF, NOTT-101 , MOF-74, MIL-1010, HKUST-1 , MOF-177, Cu-BTC), covalent-organic frameworks (imine, borates, boronic esters, pyrimidines, silicates, amides, olefins, catechols), mesoporous materials (MCM-41 , Alox, MSU-X, mesoporous carbons, silica), zeolites, and conventional ceramics with low (>0.1 m2/g) to high (up to 10,000 m2/g) surface area. An immobilization process such as this can provide customized solid materials for desalination on- demand. In addition, these solid materials can be fixed on continuous flow set-ups, which can further improve the practicality of the process by applying it to continuous processes.

1. Bottle solution (with for example a PEI-based polymer or a porous material with

immobilized diamines): After the first round of desalination, the remaining precipitate Z (polymeric form) is removed and washed with warm water to de-complex C02, since the diamine-C0 ₂ interaction is reversible at high temperature (>40°C). The water used could be fresh or salty, with up to 360 g/L salinity, saturated. This would regenerate the polymeric material for the next cycle. The advantage of using a water wash for recycling would be: low- or non-toxicity of (saline) water, less contamination and relatively low environmental impact. Minimum energy is required to dissociate CO2 from the used diamine, reducing the energy consumption needed for recycling. This means that the overall desalination process is lower in energy consumption, since it avoids the need to boil all the salty water for distillation or the need to pressurize as in RO membrane desalination.

2. Monomers (C12-diamine): after the first round of desalination, the precipitate Z is removed and subjected to organic solvents (such as but not limited to toluene, ethylacetate, acetone or a mixture of organic solvents). The mixture of an organic solvent(s) and the precipitate Z is heated to de-complex CO2. The diamine is soluble in most organic solvents, while the salt is insoluble. As such, the salts can be filtered, and the diamine regenerated after evaporation of the solvent (preferentially recycled) and ready for the next cycle. The advantage of using organic solvents are: 1 ) minimizing water contamination, 2) generating solid salt discharge (lower environmental impact), 3) fast regeneration of polymer due to easy evaporation of organic solvents. However, the absence of contamination by organic solvents for the next cycle should be rigorously confirmed based on the toxicity of the used organic solvents.

3. After the first round of desalination, the diamines are treated with supercritical C02 (>31°C, 73 atm). Most salts are not soluble in supercritical CO2 (ScCC is similar to n-hexane in terms of solvent properties) and can therefore be removed by filtration. The supercritical CO2 is released (lower temperature and pressure), and the diamines are regenerated after removing CO2 by heat-mediated decomplexation.

A representative desalination process can be seen in figure 21.

Applications of the technology

The practical applications of the present invention are as an addition or more preferably a retrofitting to the conventional desalination technologies or salinity reduction technologies as mentioned herein. Alternatively, a full substitution of the conventional desalination technologies or salinity reduction technologies as mentioned herein may be desirable in certain application areas. Accordingly, the present technology can be applied in several application areas which can be divided into five overall market segments with different needs:

1. Potable water for aid relief and safety equipment

2. Short-term/temporary potable water supply for smaller communities, e.g. for small

communities, temporary use, military applications, emergency situations etc.

3. Long-term/permanent potable and agricultural water supply for regions or nations e.g. water-stressed regions and nations, such as California, India, the Middle East, South Asia, Australia, Singapore, South Africa, Mexico etc.

4. Process water of various kinds, qualities and quantities for the industry

5. Purification of saline wastewater and brine

Potable water for aid relief and safety equipment

Desalination can be a critical process in the case of emergency where the amount of potable water is limited or even at all available. The molecules of the present invention and uses hereof can be applied in a range of uses in such emergency situations which includes but are not limited to the production of potable water in lifeboats and/or rafts on commercial vessels and ships, offshore platforms, yachts, boats and other marine vessels. In addition to lifeboats and/or rafts the present technology can be used to provide desalinated water as emergency back-up for consumers such as but not limited to private yachtsmen, sea kayakers, and consumers in other sea-based leisure segments. Additionally, the technology can be applied in military use, such as but not limited for use by soldiers during exercises and warfare as emergency fresh water supply solutions where only saline water is available.

In yet an embodiment of the present invention, the present technology can be used to produce potable water in coastal areas during crisis situations, such as short-term or long-term water stressed locations e.g. crisis situations, where freshwater supply is unstable or unavailable.

For the above applications areas, the present technology can be applied to a semi-permanent desalination kit. In such a desalination kit the desalination process can be performed several times due to the recyclable nature of the method of the present invention. The desalination kit can be selected from the group comprising a desalination bottle; a small, portable container and a portable bag where the CCh-responsive materials are included or can be added to the bottle, e.g. in a separate compartment of the desalination kit. By applying the cyclic steps of the present method, the desalination kit can be reused multiple times. The only energy input required is CO2, preferably from a small CO2 cylinder, which can be supplemented with CO2 from human exhale breath which is 10 times enriched with CO2 compared to the atmospheric air. The process can furthermore be operative with atmospheric air; however, such application will require prolonged desalination time.

Thus, an aspect of the present invention relates to a kit for desalination comprising a compound of formula (I) and means for separating precipitate Z from the aqueous solution.

In a further embodiment of the present invention the kit is an emergency kit. In a further embodiment of the present invention the kit is portable.

Short -term/temporarv potable water supply for smaller communities

The present invention can furthermore be applied to movable and/or small-scale desalination containers . Such movable and/or small-scale desalination containers can be used for areas such as but not limited to technical equipment for yachts or smaller boats; people being dependent on well water in arid regions where over-exploitation over decades has turned the groundwater too saline for drinking purposes; where people are living near the sea, near brackish water where freshwater supply is limited or unstable; camps or temporary bases for military or other operational purposes as well as in crisis situations. In addition, the present technology can be applied to the recreational industry, such as but not limited to seaside resorts, where the need for potable water today is provided through the use of conventional reverse osmosis.

The requirements for capacity and purified water needed by each segment vary due to the circumstances of use. A container capacity of approximately 10 litres of desalinated water per hour will suffice for 15-20 persons with an average use of 12-16 litres of water per day per person. For applications where the desalination takes place at open sea, the need for a purifying step will be minor, as the feedwater at open sea which in most cases is clear. However, if the desalination process takes place closer to the coast or inland, a water purification step must be added either in the movable and/or small-scale desalination container solution or as an extra process steps to be performed after the desalination.

The same assumptions apply for the military segment. However, military camps might require even larger capacity ranging to anything between 20 and 200 litres per hour instead of having multiple smaller containers. A purification step will still be available if needed.

The use of movable and/or small-scale desalination containers in crisis situations, the required water supply per person is lower, as it is to be used for survival and not everyday life. The US Centre for Disease Control & Prevention recommends 4 litres per person per day. With a 10-20 litres capacity per hour, a container could supply water for 60-120 persons, and with a 100-200 litres capacity per hour, a container would supply 600-1.200 persons. A purification step is preferable, but not always necessary.

The use of high purity C02 will accelerate the desalination process by taking advantage of controlled desalination processes under regulated temperature. The automated desalination and recycling system will provide a continuous potable water generation of 10-200 litres/hour by using minimum amounts of electricity and heat sources. Both the electricity and the heat can be provided by small solar panels.

Lonq-term/permanent potable and agricultural water supply for regions or nations

Today, more than 150 countries are utilizing or considering desalination technologies; to name a few: Saudi Arabia, United Arab Emirates, Israel, Spain, Portugal, Greece, Japan, Singapore,

China, India, Australia and the United States (Gulf of Mexico, California, Florida and Arizona).

The Middle East and Africa account for 53% of the 2016 desalination market due to the recurrent occurrence of multi-year and multi-state droughts and decreasing access to freshwater sources. Also, the US, Australia, China and India are heavy users. And the demand is expected to go up in the future. The demand for plant-size desalination technology comes from regions or nations (governments/ municipalities) in need of a long-term/permanent and reliable potable and agricultural water supply. Operators can be both public or private.

An average desalination plant produces around 100.000 m3/day. However, an increasing amount of super-size facilities are showing up such as the Israeli Sorek plant which has a capacity of 627.000 m3/day and provides -20% of the nation’s water supply. However, there is also a need for more flexible and movable facilities. Accordingly, plants based on 20-40 feet storage containers (modular facilities) are also in demand, and such plants produce smaller volumes of around 2.000 m3/day. Such units can be moved in case the source water quality decreases or according to need e.g. during multi-year droughts.

Accordingly, one embodiment of the present technology will be as a pre-treatment process step in reverse osmosis desalination plants and thereby increasing the capacity and decreasing the operating costs of such existing facilities by lowering the water salinity significantly upstream of the reverse osmosis step. A further embodiment of the present technology will be as the only desalination process step in new water facilities (modular and/or full-size). Yet another embodiment will be for desalination for industrial process water.

Process water of various kinds, qualities and quantities for the industry

Industry accounts for -20% of the total worldwide water consumption where most water is being used for cooling, rinsing, cleaning and other manufacturing processes. The manufacturing processes do not all require the same low saline quality as drinking water. Accordingly, the cost and efficiency effect of using less saline water or cheaper potable water in the manufacturing processes are important. The demand comes from a wide range of industries, but especially the chemical, food, pharma, electronics, oil and gas, and construction industries are heavy users of process water.

Salinity status classifications, by total salt concentration

Fresh < 500 Drinking and all irrigation

Brackish 1 000 2 000 Irrigation certain crops only; useful for most stock

Highly saline 10 000-35 000 Very saline groundwater, limited use for certain livestock

Drinking water

Salinity relates to the amount of salt in the water. Typically, water contains two or more of the following salts: Sodium, potassium, calcium, magnesium, chloride, sulphate, bicarbonate, carbonate and nitrate.

One of the main methods of defining the concentration of salt in water is Total Dissolved Solids (TDS), which is measured by evaporating water to dryness and weighing the solid residue.

World Health Organization comments on guideline TDS levels for drinking water are:

“The palatability of water with a total dissolved solids (TDS) level of less than about 600 mg/L is generally considered to be good; drinking-water becomes significantly and increasingly unpalatable at TDS levels greater than about 1000 mg/L.”

Based on taste, the following categories are provided to rate drinking water according to TDS concentrations:

Irrigation

Salinity damage to plants is commonly attributed to an increase in osmotic potential, which reduces the plant roots' ability to extract water and accordingly, reduces photosynthesis and transpiration. Accordingly, it is a further embodiment of the present technology to be applied for irrigation purposes where excess of salts can be removed before the water reaches the field, by desalinating the water allocated to irrigation.

Discharge standards for salt components in wastewater discharged by industries to inland recipients are expected to become a growing problem which limits the growth potential for such industries. Thus, desalination of high-saline process water streams will most probably be a growing market for energy efficient desalination technologies. Accordingly, it is a further embodiment of the present technology to be applied for salinity reduction and potentially salt recovery from high saline industrial process water streams.

The present invention can furthermore be used to treat saline wastewater and rinse water before releasing such water is released, or in situations of reclamation or reuse of wastewater and/or industrial process water.

In addition, the present invention can be used for precipitation and capturing of brine/salt concentrates for recovery and utilization, e.g. extraction of salts from high concentration process streams for subsequent industrial reuse and/or removal of salt discharge as a barrier for increased industrial production.

Today, disposal of brine, or highly concentrated salt-laden process waste stream containing spent cleaning agents or solutions containing toxic chemicals is a major problem. In particular, major coastal desalination facilities usually release their respective concentrates into estuaries and oceans. The brine thus discharged is typically almost twice as saline as the receiving waters. Also, the density of the discharged brine is usually higher than that of the receiving waters. Therefore, the brine manifests a propensity to sink and gradually spread along the floor of the ocean.

Effective measures therefore need to be implemented in order to ensure safe disposal of desalination concentrates and other toxic components present in the discharge from desalination plants.

Another valuable resource that can be recovered from brine using the present technology is the salt present in the brine, which has various constituents with numerous commercial purposes.

General

It should be understood that any feature and/or aspect discussed above in connections with the compounds according to the invention apply by analogy to the methods described herein.

The terms X and Y are used interchangeably.

The following figures and examples are provided below to illustrate the present invention. They are intended to be illustrative and are not to be construed as limiting in any way.

Tables

Table 1. Desalination of the model seawater (15 ml_, 35 g/L) solution using organic amines and CO2 (CO2 was introducted for 60 seconds via blanket method). * The reduction percentile was calculated by starting from 35 g/L based on conductivity meter with a dedicated NaCI probe. The start salinity indicates the initial salinity before the diamine was added. Table 2. Salinity reduction measured by benchtop ²³Na and ³⁵CI NMR with 20 ml_ saline water samples and C02

BRIEF DESCRIPTION OF THE FIGURES

Figure 1

Figure 1 shows the C0 ₂-mediated desalination using diamine (I).

Figure 2

Figure 2 shows experiments on salinity/conductivity. (Left) Control experiment of

salinity/conductivity of Dl-water with C02 without amines. (Right) with saline water.

Figure 3

Figure 3 shows representative diamine structures.

Figure 4

Figure 4 shows desalination Sample (Left) after introducing CO2, and a plot with salinity over time using a diamine in saline water (35 g/L, initial salinity).

Figure 5

Figure 5 shows comparison of various diamines and C0 ₂-responsive molecules in terms of salinity reduction. The alkylated diamine (shown in figure 6) outperformed all other tested molecules.

Figure 6

Figure 6 shows a model desalination experiment with 20 mL of C12-NC3NMe2 (200 mL of saline water, 35 g NaCI/L, was tested). The picture shows phase separation of diamine/C0 ₂ complex- NaCI phase and aqueous phase (after cooling down the mixture at 5 °C for 5 minutes).

Figure 7

Figure 7 shows representative polymerization scheme for diamine-based styrene polymers.

Figure 8

Figure 8 shows representative synthesis of alkylated diamine.

Figure 9

Figure 9 shows desalination capacity of various tested amine-based molecules. Note that C12- alkylated diamine showed significant reduction of salinity under tested conditions (35000 ppm NaCI aqueous solution at room temperature, CO2 introduced under 1 atm). Various diamines without linear alkyl chain substituted showed no activity toward reduction of salinity. The optimal performance was obtained with 1 ,3-diamines with a C12 substituent. Materials were directly used from commercial sources or prepared via one-step alkylation reactions. Desalination process was conducted by using CO2 (1 atm) with 10wt% of diamine compared to saline water and salinity was measured by following conductivity. Figure 10

Figure 10 shows effects of alkyl-chain length on desalination process using the C3-diamine (depicted in the figure, N-dimethyl-propyl 1 ,3-diamine). Different alkyl groups with an order of chain lengths, from octyl to hexadecyl, were introduced to determine the molecular effects on the performance of desalination. The optimal performance was observed with C12 (dodecyl). C1 1 (undecyl), C16 (hexadecyl) and C10 (decyl) also showed compatible performances under identical conditions as previous figure.

Figure 11

Figure 11 shows de-salt (desalination) process using C12-diamine and CO2 with various salts (CaCL, NaNCh, NaSC , KCI, NaNCh, NasPC , amounts indicated in the figure) measured by conductivity over time of C02 introduction to demonstrate the robustness and the general scope of the invention. Not only Na cation or Cl anion, other ions including Ca(2+) and K(+) were tolerated under desalination conditions using the diamine (C12-NC3NMe2) and CO2.

Figure 12

Figure 12 desalination process using seawater compared with model seawater (NaCI aqueous solution) measured by conductivity by function of time of CO2 introduction. The seawater collected from Oresund showed low salinity (10,000-12000 ppm), therefore, the experiment started with IQ- 12 g/L salinity (10,000-12,000 ppm TDS). After treating with CO2, salinity was reduced to 2,900 ppm, equal to the model seawater (35,000 ppm).

Figure 13. Desalination capacity of various tested molecules.

Figure 14. The effect of aliphatic alkyl chains in desalination performance.

Figure 15. Desalt process using the optimized diamine and CO2 with various ions.

Figure 16. Desalination process using seawater compared with model seawater (NaCI aqueous solution) measured by conductivity by function of time of CO2 introduction (Left). Desalination process at different concentrations of NaCI in model systems (Right).

Figure 17. Desalination using PEI-based diamines.

Various PEI (polyethyleneimine)-based polymers were evaluated for desalination. We found that the alkylation degree is critical to obtain desirable results namely to reduce salinity under CO2. The presence of specific alkylation degree is to balance the solubility and C0 ₂-capture performance of the polymer, thus affecting the ion capture (ion exchange) process to induce salinity reduction. Figure 18. Recycling of PEI-based polymers for repeated desalination processes

(1-3 cycles: closed circles; 4 ^th recycle: open circles).

The obtained PEI-based polymer was utilized to identify recyclability. After washing the polymer with water (at 70 - 90°C), the polymer was reused for next desalination cycle. The result shows that the initial concentration (50 NaCI g/L) was reduced further down to 40 g/L after 4 cycles.

Figure 19. Effect of concentrations of diamines in desalination

Measurements for critical micelle concentration was attempted: various concentration of the diamine (formula 1 A) was used for desalination process. The result indicated that there is critical concentration of formula 1A to induce higher salinity reduction (between 0.03 - 0.04 M), showing that minimization of the used formula 1 A is possible depending on the source of saline water.

Figure 20. Temperature dependent desalination

At various temperature, the model desalination process was conducted using formula 1A. This indicate the process is reversible at various temperature therefore it may be energy efficient to revert the process for recycling. At higher temperature, greater reduction of salinity was obtained which indicated that the dehydration of micelles could be facilitated at elevated temperature.

Figure 21 shows a representative desalination process.

EXAMPLES

Example 1 - Design of desalination

The CCte-mediated desalination using diamine (I) is generally described in figure 1.

Alkylchain-modified diamine (left) is treated with CO2 in saline water or seawater. Upon the spontaneous formation of carbamate or bicarbonate, or carbonate salt of ammonium cation, the C0 ₂-responsive unit is now activated to chelate NaCI (or salt). This ion-ion interaction now can trigger self-aggregation of the molecular unit by taking advantage of lone alkyl chain induced by Van der Waals forces. The outer sphere of the obtained high molecular weight molecular network is presumably hydrophobic therefore, exhibit low solubility in aqueous solutions. The spontaneous precipitation occurs within 60-120 seconds, where the separation can be performed to provide salinity-reduced water.

Example 2 - Determination of salinity

Salinity was determined by measuring conductivity of the solution by employing electrode specialized for NaCI and other salt for water quality control (figure 2). Background CO2 effect was measured to identify the conductivity difference in the presence of carbonate ions in deionized water and saline water in the absence of diamine additives. The observed conductivity changes were negligible (up to 60 m8/ath, note that NaCI 3.5 g/L corresponds to 6200 m3/ath). These experiments assured us that the effect of CO2 in salinity measurement will be only positive, therefore, the observed salinity reduction is not related to background CO2 introduction to the solution (figure 2). The results are shown in figures 4-6, 9-12, and table 1.

Example 3 - Desalination by bubbling C02

As mentioned in Example 2, salinity was determined by measuring conductivity of the solution by employing electrode specialized for NaCI and other salt for water quality control. Pure CO2 was introduced by syringe tubing or similar set-ups. The exothermic C0 ₂-complexation generates fluctuation the C0 ₂-absoprtion therefore, temperature control might be necessary. However, under operating reaction conditions, we employed reaction conditions without temperature control to show the easiness of the application of the invention in practical sense.

Example 4 - Large scale synthesis of diamines

Diamine was placed in a round bottle flask and alkyl halide was added dropwise at 0 °C.

Temperature control is important to minimize multiple alkylation reaction, which hampers purification processes. After 24 h the addition of alkyl halides was finished, the reaction was further stirred for additional 16 hr. The process of the reaction was monitored by analysing crude 1 H NMR. The reaction mixture then extracted with heptane and pentane. The remaining diamine was distilled-off from the product to afford analytically pure alkylated diamine.

Example 5 Synthesis of polymeric diamine

The stabilizer (t-butyl catechol) was removed from styrene and commercial 1 ,4-divinylbenzene by washing chemicals with excess of 1 per cent aqueous sodium hydroxide aqueous solution and twice with water. To a solution of water, acacia gum and sodium chloride, was added a styrene, 1 ,4-divinyl benzene, azobisisobutyronitrile, diamine and chlorobenzene. The reaction mixture was deoxygenated by purging with argon atmosphere for at least 30 min at room temperature. Then, the reaction vessel was heated to 110 and stirred for 12 hours under N2 atmosphere. After cooling to room temperature, the reaction mixture was filtered and washed with water. The polymeric residue was suspended in 300 ml_ of water and stirred for at least 1 hour and then filtered. The filtered residue was suspended in 400 ml_ of methanol and stirred for 1 hour and then filtered. After washing with adequate solvents, the polymer was dried overnight in vacuo to afford 6 g of diamine functionalized polymer as a white solid

Example 6 Simplified synthesis of polymeric diamine

To a solution of PEI (polyethyleneimine, random polymer) in THF, alkyl halide (0.5 - 2 equivalent based on the nitrogen contents of PEI) was added dropwise while keeping the reaction temperature to 0 degree. The mixture was then vigorously stirred for 18 h, then the reaction mixture was washed with organic solvents and water. The remaining gel-like polymers was then washed with acetone/water mixture and then acetone only to afford yellow powder after air dry.

Example 7 Desalination exemplary method

Diamine was placed in a container filled with aqueous solution of NaCI. Then CO2 was introduced either by bubbling 100% CCte or by slowly feeding CO2 to the mixture (blanket method), which induced precipitation of NaCI-diamine-CCh complex. The used CO2 is either pure CO2 or CO2- enriched gas or air. The obtained solid was further analyzed by primarily conductivity meter and salinity meters. And elemental analysis, infrared spectroscopy and high-resolution mass spectroscopy was implemented to analyze the chemical composition of the precipitates.

The precipitates are recycled by following procedures:

The mixture was dissolved in toluene which can solubilize organic diamines. By applying mild heat or waste heat, CO2 can be liberated via de-complexation. The reduced salt affinity from the diamine will release salt, particularly NaCI in organic solvent, therefore, recovering the diamine in the solution after evaporating the used organic solvent. Or

A polymeric diamine which is decorated with long alkyl chain, preferably decyl, undecyl, dodecyl, was added to the saline water and CO2 was introduced by bubbling the solution. After 2-3 minutes, the salinity-reduced solution was decanted, and the wet polymer was heated in warm water (>40 °C) to facilitate decomplexation of CO2. The polymer was washed with heated saline or brackish water to removed remaining salts and then used for the next cycle of desalination.

Example 8 Desalination exemplary method II

N,N-dimethyl-1 ,3,-propylenediamine was placed in a round bottle flask and dodecyl bromide was added dropwise at 0 °C. After completion of addition, the solution was warmed up to room temperature and stirred for 18 hr. The alkylated diamine was extracted by using heptane and dried under reduced pressure. The obtained diamine was then dissolved in aqueous solution of NaCI. Then CO2 was introduced either by bubbling 100% CO2 or by slowly feeding CO2 to the mixture (blanket method), which induced precipitation of NaCI-diamine-CCh complex. The obtained solid was further analyzed by elemental analysis, infrared spectroscopy and high-resolution mass spectroscopy to analyze the chemical composition of the precipitates.

For the purpose of the present invention, various diamines which show high desalination capacity were demonstrated on 20 mL - 100 ml_ scale. The tested diamines are based from (a) 1 ,2- ehtylenediamines, (b) 1 ,3-propylenediamines, (c) amino alcohols, (d) polymeric amines in Figure 3. Table 1 summarizes selected examples of tested diamines and related molecules for salinity reduction experiments.

Example 9 Desalination exemplary method III

Methodology

Design of desalination

The C0 ₂-mediated desalination using diamine will be conducted using general method

as described below: Alkylchain-modified diamine is treated with CO2 in saline water or seawater. Upon the spontaneous formation of carbamate or bicarbonate, or carbonate salt of ammonium cation, the CC -responsive unit is now activated to chelate NaCI (or salt). These ion-ion interactions can now trigger self-aggregation of the molecular unit by taking advantage of lone alkyl chain induced by Van der Waals forces. The outer sphere of the obtained high molecular weight molecular network is presumably hydrophobic therefore, exhibit low solubility in aqueous solutions. The spontaneous precipitation occurs within 60-120 seconds, where the separation can be performed to provide salinity-reduced water (see figure 1 ). Determination of salinity

Salinity was determined by measuring conductivity of the solution by employing electrode specialized for NaCI and other salt for water quality control (figure 2). Background CO2 effect was measured to identify the conductivity difference in the presence of carbonate ions in deionized water and saline water in the absence of diamine additives. The observed conductivity changes were negligible (up to 60 uS/cm, note that NaCI 3.5 g/L corresponds to 6200 m8/ath). These experiments assured us that the effect of C02in salinity measurement will be only positive, therefore, the observed salinity reduction is not related to background CO2 introduction to the solution.

Benchtop NMR (Tveskaeg®) was employed to precisely determine concentrations of sodium cation and chloride ions in solution state. The measurement was conducted at room temperature with temperature compensation.

Desalination by bubbling CO2

As mentioned above, salinity was determined by measuring conductivity of the solution by employing electrode specialized for NaCI and other salt for water quality control. Pure CO2 was introduced by syringe tubing or similar set-ups. The exothermic CCh-complexation generates fluctuation the CC -absoprtion therefore, temperature control might be necessary. However, under operating reaction conditions, we employed reaction conditions without temperature control to show the easiness of the application of the invention in practical sense.

Radical Polymerization

The stabilizer (f-butyl catechol) was removed from styrene and commercial 1 ,4-divinylbenzene by washing chemicals with excess of 1 per cent aqueous sodium hydroxide aqueous solution and twice with water. To a solution of water, acacia gum and sodium chloride, was added a styrene, 1 ,4-divinyl benzene, azobisisobutyronitrile, diamine and chlorobenzene. The reaction mixture was deoxygenated by purging with argon atmosphere for at least 30 min at room temperature. Then, the reaction vessel was heated to 110 °C and stirred for 12 hours under N2 atmosphere. After cooling to room temperature, the reaction mixture was filtered and washed with water. The polymeric residue was suspended in 300 ml_ of water and stirred for at least 1 hour and then filtered. The filtered residue was suspended in 400 ml_ of methanol and stirred for 1 hour and then filtered. After washing with adequate solvents, the polymer was dried overnight in vacuo to afford 6 g of diamine functionalized polymer as a white solid.

Simplified synthesis of polymeric diamine

To a solution of PEI (polyethyleneimine, random polymer) in THF, alkyl halide was added dropwise while keeping the reaction temperature to room temperature with water bath. The mixture was vigorously stirred for 18 h, and the reaction mixture was washed with organic solvents and water. The remaining gel-like polymers was then used without further purification.

Discussion

We performed the desalination experiment using a model seawater solution (15 ml_, NaCI 3.5 g/L, measured by a specialized salinity meter). A diamine (2 ml_, 10 equivalents based on NaCI) was dispersed in the NaCI solution, and CO2 was bubbled. Immediate precipitation was observed, while the temperature of the solution increase to 2-3 °C due to the exothermicity of the process. More importantly, the salinity of the model sea-water solution dropped to 0.6 g/L— which implies a >85% NaCI reduction— after 2 minutes. Furthermore, the test at the‘real’ concentration of NaCI in aqueous solution (NaCI 35 g/L) showed also promising result, showing 90% reduction of salinity in 60 second, by introducing CO2‘slowly’ while stirring the solution with magnetic stirrer. These preliminary results highlight the importance of C02 concentration to the formation of aggregates, and more in-depth studies on kinetics and other experiments to quantitative C02-diamine complexes will be followed.

At this juncture, to rule out the effect of the applied C02 in the conductivity measurement and therefore salinity measurement, control experiments were performed in the absence of diamines under conditions with deionized water and saline water. The increase of conductivity was negligible (Figure 2). Although the solubility of CO2 in water would change the conductivity of the solution by forming carbonic acid and (bi)carbonate, we concluded that the solubilized C02 and related ions would not affect our salinity measurement under our experimental conditions.

After identifying the performance of the diamine we decided to reveal the structure-performance relationship of the diamine-mediated desalination process. We have tested more than 50 different nitrogen-based compounds including polymeric materials. As summarized in Table 2, most of conventional diamines, amino alcohols and their derivatives resulted in homogeneous solution, therefore, only increased conductivity was observed (up to 90%) which can be explained by more efficient formation of carbonate and bicarbonate ions After this optimization, we concluded that diamine-based CC -responsive materials were optimal for this process. Under“real”-conditions (35 g/L NaCI aq. solution), we achieved 89% reduction of NaCI within 60 seconds. And moreover, this NaCI-binding process was highly efficient such that the reduced salinity was maintained after long period of time (>12 hours), which is critical for further separation of the salt out of the aqueous system via ultra-filtration and other techniques which are under-development in our laboratory.

Although the chain length of the alkylated diamine plays a significant role in the desalination and the capacity of salinity reduction, we observed that three tested diamines in Figure 16 showed similar trend of salinity reduction under otherwise identical conditions. It is evident that the chain length of C12 is optimal, while longer chain length is detrimental in terms of desalination performance (C13-C16). C8 and C9 groups were also tested, however, displayed lower salinity reduction, which might be ascribed to the higher hydrophilicity. The control of ambivalent hydrophobic and hydrophilic nature seems critical to attain the desired desalination performance. Also, it would be plausible that the formation of (reverse)micelles can be manipulated by the chain length, therefore affecting the desalination capacity. Additionally, the observed salinity was increased after certain time in the case of C10 and C1 1 -decorated diamine, indicating the instability of NaCI/diamine or ammonium carbonate. The presence of adequate length of alkyl- chain showed superior stability of this state, indicated by the stable salinity over time (after 200 seconds), maintaining low salinity after stopping CO2 supply. We presumed that during the CO2 injections, diamine-CCh complexes form kinetically viable supramolecular complex, which were attempted to be analysed by DLS. However, due to the complexity and reversibility of the system, no solid conclusion was deduced. This thermodynamically unstable, kinetically viable state can be further understood as far-from-equilibrium state, by consuming CO2 as a molecular fuel, while forming carbonate and carbonic acid-diamine complexes. The presence of multiple ions will be critical to engineer the supramolecular structure.

Considering that seawater is a complex mixture of salts, we tested various salts for our desalination process to explore the possibility of desalting process of individual salts. As summarized in Figure 17, various salt showed in general decrease of conductivity by introducing the diamine upon C02 injection at room temperature. Although it is difficult to rationalize the trend, various ion-containing aqueous solutions can in principle be applied for“desalt” process. Within 100-200 seconds, minimum conductivity was obtained which can be maintained in the case of fer example, NaCI, NasPC , NaNCb, Na2SC>4, whereas fast reverse processes were observed with KCI, CaCb, and NaNCte. In this regard, real seawater samples collected from many different places were tested (Figure 18). Regardless the source of the seawater sample, salinity reduction was observed while the minimum salinity and its remaining time period vary. Further analysis of the chemical and physical changes of water samples after ultrafiltration would be necessary to investigate the process.

To further facilitate easy separation and regeneration of the diamine polymers, these can be immobilized or supported on a polymeric material. In addition to enabling a more efficient recovery of the diamine, the use of polymeric diamines will also minimize risk of potential contamination of the produced water with excess diamine. Polyethyleneimines (PEI) - amine-based polymers - have initially been chosen as the substrate and optimized by branch structure for optimal performance. The resulting polymer consists of repeating units of amine and is well known for applications in drug delivery, as detergents in water treatment and cosmetics, as well as in CO2 capture. Chemical functionalization of PEI polymers is a fairly simple chemical process, and the Lee group showed that alkyl chain-modified PEI can be applied in the desalination process (Figure 17). For example, C16-alkylchain modified PEI presented superior desalination capacity compared to others. Moreover, the obtained polymer can in the initial lab-scale experiments be recycled more than 4 times. Accordingly, these polymeric diamines show promising recyclability and

processability, resulting in up to 10% salinity reduction (from 50 to 45 g/L after 4 cycles) from high saline water by repeating the cycle with the same polymer (Figure 20). These results indicate the potential of the polymer-supported diamines for desalination and water purification with CO2, without any external energy sources for filtration or thermal distillation processes. Based on these preliminary results, next steps are to improve the capacity and the efficiency of the desalination process with immobilized diamines. In addition, the chosen diamines, both monomeric and polymeric will be evaluated for their toxicology profile to verify and compare the performance in desalination and in vivo and environmental effect.

To investigate the mechanism of the desalination, we conducted salinity measurement at different concentrations of diamine, to determine the critical micelle concentration (CMC). Our attempts with DLS (dynamic light scattering) measurement was insufficient to draw any conclusion due to the low correlation prohibited acquiring reasonable data in terms of micelles and particle sizes and distribution. Therefore, we decided to use conductivity (salinity) changes with respect to the amounts of diamines. By varying the concentration, we observed different behaviors of diamine and salinity reduction in 20 mL solution of NaCI. Between 0.03 and 0.04M concentration of diamine, significant difference of salinity was observed at the same period of time, indicating the presence of CMC. Variations with temperature and salts further confirmed that the aggregation process is affected by external temperatures. It is postulated that the dehydration of (reverse)micelles is facilitated at higher temperatures therefore, more significant salinity reduction was induced at > 40 °C. Further analysis of diamine- C02 interactions was conducted by 1 H and 13C NMR spectroscopy.

To verify the obtained results regarding desalination, 23Na and 35CI NMR spectroscopy was employed to precisely determine the concentrations of sodium and chloride ions in the solution before and after the desalination process with monomeric diamines and polymeric diamine (PEI- C16). In this measurement we observed up to 12% chloride ion capture from the parent solution by using polymeric diamine and carbon dioxide. It is promising step toward ideal desalination, when it is equipped with higher capacity and recyclability (see table 2).

ITEMS

1. A method for desalination of an aqueous solution comprising a salt of formula M ^a+X ^b (mixture A), comprising the steps; i) contacting an amine of formula (I) with mixture A to generate an aqueous mixture comprising amine and salt (mixture B), ii) contacting mixture B with CO2 for a sufficient time period to co-precipitate the amine of formula (I), M ^a+, and X ^b to generate a precipitate (Z), and iii) isolate the precipitate (Z) to obtain an aqueous mixture C of lower salinity than aqueous mixture A, wherein the amine formula (I) is defined by:

Formula (I) wherein,

Ri, R ₂ and R3 is selected independently from H, Me, Et, n-Pr, i-Pr, n-Bu, i-Bu, t-Bu, Ph, Benzyl, and Aryl,

X is selected from C=0, C=NH, C=S, CHF, CH2 and CF2,

R ₄ and R5 is selected independently from CH3, H and F, n is an integer from 1-4 included, m is an integer from 3-18 included, and wherein

M ^a+ is a cation for which a is 1, 2 or 3, and

X ^b is an anion for which b is 1, 2 or 3. 2. The method according to item 1 , wherein ⁺M is selected from the group consisting of a monovalent metal cation, a divalent metal cation, a trivalent metal cation, and an ammonium ion.

3. The method according to item 2, wherein the monovalent metal cation is selected from the group consisting of Li ⁺, Na ⁺, K ⁺, Rb ⁺, Cs ⁺, Fr ⁺, Ag ⁺, Cu ⁺.

4. The method according to item 2, wherein the divalent metal cation is selected from the group consisting of Be ²⁺, Mg ²⁺, Ca ²⁺, Sr ²⁺, Ba ²⁺, Ra ²⁺, Zn ²⁺, Mn ²⁺, Co ²⁺, Ni ²⁺, Cu ²⁺, Ra ²⁺, Cd ²⁺.

5. The method according to item 2, wherein the trivalent metal cation is selected from the group consisting of Al ³⁺, Fe ³⁺, Ru ³⁺, Sc ³⁺, Rh ³⁺, ln ³⁺, Yb ³⁺.

6. The method according to item 2, wherein ⁺M is an ammonium ion and phosphonium ion.

7. The method according to items 1-6, wherein Xb is a monovalent halogen is selected from the group consisting of F , Cl , Br, I , NO3 (nitrate).

8. The method according to items 1-6, wherein Xb is phosphate.

9. The method according to items 1-6, wherein Xb is carbonate.

10. The method according to items 1-6, wherein Xb is sulfate.

1 1 . The method according to items 1-6, wherein Xb is bicarbonate.

12. The method according to items 1-1 1 , wherein the salt is selected from the group consisting of NaCI, KCI LiCI, LiBr, Lil, LiF, NaF, NaBr, Nal, KF, KCI, KBr, Kl, Na ₂S0 ₄, K2SO4, MgSC , CaF ₂, CaCI ₂, CaBr ₂, Cal ₂, CaSC .

13. The method according to items 1-12, wherein the salt is NaCI.

14. The method according to items 1-13, wherein n in formula (I) is selected from the group consisting of 1 , 2, 3, or 4.

15. The method according to items 1-14, wherein n is 1.

16. The method according to items 1-14, wherein n is 2.

17. The method according to items 1-14, wherein n is 3.

18. The method according to items 1-14, wherein n is 4.

19. The method according to items 1-13, wherein m in formula (I) is selected from the group consisting of 3, 4, 5, 6, 7, 8, 9, 10, 1 1 , 12, 13, 14, 15, 16, 17 or 18. 20. The method according to items 1-19, wherein m is 6-18.

21 . The method according to items 1-19, wherein m is 6.

22. The method according to items 1-19, wherein m is 7.

23. The method according to items 1-19, wherein m is 8. 24. The method according to items 1-19, wherein m is 9.

25. The method according to items 1-19, wherein m is 10.

26. The method according to items 1-19, wherein m is 1 1 .

27. The method according to items 1-19, wherein m is 12.

28. The method according to items 1-19, wherein m is 13. 29. The method according to items 1-19, wherein m is 14.

30. The method according to items 1-19, wherein m is 15.

31 . The method according to items 1-19, wherein m is 16.

32. The method according to items 1-19, wherein m is 17.

33. The method according to items 1-19, wherein m is 18. 34. The method according to items 1-33, wherein m has a degree of unsaturation of 2.

35. The method according to items 1-33, wherein m has a degree of unsaturation of 3.

36. The method according to items 1-33, wherein m has a degree of unsaturation of 4.

37. The method according to items 1-36, wherein formula (I) is any of the compounds listed in figure 3. 38. The method according to items 1-37, wherein Ri is H.

39. The method according to items 1-37, wherein Ri is Me.

40. The method according to items 1-37, wherein Ri is Et.

41 . The method according to items 1-37, wherein Ri is n-Pr.

42. The method according to items 1-37, wherein Ri is i-Pr. 43. The method according to items 1-37, wherein Ri is n-Bu.

44. The method according to items 1-37, wherein Ri is i-Bu.

45. The method according to items 1-37, wherein Ri is t-Bu

46. The method according to items 1-37, wherein Ri is Ph.

47. The method according to items 1-37, wherein Ri is H Benzyl.

48. The method according to items 1-37, wherein Ri is Aryl.

49. The method according to items 1-48, wherein R ₂ is H.

50. The method according to items 1-48, wherein R ₂ is Me.

51 . The method according to items 1-48, wherein R ₂ is Et.

52. The method according to items 1-48, wherein R ₂ is n-Pr.

53. The method according to items 1-48, wherein R ₂ is i-Pr.

54. The method according to items 1-48, wherein R ₂ is n-Bu.

55. The method according to items 1-48, wherein R ₂ is i-Bu.

56. The method according to items 1-48, wherein R ₂ is t-Bu

57. The method according to items 1-48, wherein R ₂ is Ph.

58. The method according to items 1-48, wherein R ₂ is Benzyl.

59. The method according to items 1-48, wherein R ₂ is Aryl.

60. The method according to items 1-59, wherein R3 is H.

61 . The method according to items 1-59, wherein R ₃ is H.

62. The method according to items 1-59, wherein R3 is Me.

63. The method according to items 1-59, wherein R3 is Et.

64. The method according to items 1-59, wherein R3 is n-Pr.

65. The method according to items 1-59, wherein R3 is i-Pr. 60. The method according to items 1-59, wherein R3 is n-Bu. 66. The method according to items 1-59, wherein F¾ is t-Bu.

67. The method according to items 1-59, wherein F¾ is Ph.

68. The method according to items 1-59, wherein F¾ is Benzyl.

69. The method according to items 1-59, wherein F¾ is Aryl.

70. The method according to items 1-69, wherein X is C=0.

71 . The method according to items 1-69, wherein X is C=NH.

72. The method according to items 1-69, wherein X is C=S.

73. The method according to items 1-69, wherein X is CHF.

74. The method according to items 1-69, wherein X is CH2.

75. The method according to items 1-69, wherein X is CF2.

76. The method according to items 1-75, wherein R4 is CFh.

77. The method according to items 1-75, wherein R4 is H.

78. The method according to items 1-75, wherein R4 is F.

79. The method according to items 1-78, wherein R5 is CH3.

80. The method according to items 1-78, wherein Rs is H.

81 . The method according to items 1-78, wherein Rs is F.

82. The method according to items 1-81 , wherein the aqueous solution is selected from the group consisting of seawater, brackish water, saline water, brine, salt-enriched water, water containing salts, water with ion conductivity, and water with ions.

83. The method according to items 1-82, wherein the aqueous solution is seawater.

84. The method according to items 1-83, wherein the salt concentration of mixture A is 0.05 - 40% salinity level (equal to 0.1 - 400 g/L or g/kg).

85. The method according to items 1-84, wherein the salt concentration of mixture C is less than 0.05% salinity level (fresh water: less than 0.5 g/L).

86. The method according to items 1-84, wherein the salt concentration of mixture C is above 0.05% but less than 3% salinity level (brackish water: 0.05-3% salt, 0.5 - 30 g/L). 87. The method according to items 1-86, wherein the aqueous solution (mixture A) furthermore comprises a compound selected from the group consisting of organic amines of formula (I), ammonium salt of formula (I), ammonium carbamate of formula (I), ammonium carbonate salt of formula (I), and ammonium bicarbonate salt of formula (I), carbamate of formula (I) intermediate or amine-C02 complex of formula (I).

88. The method according to items 1-87, wherein the salt concentration of mixture C is no more than 15 % of mixture A.

89. The method according to items 1-88, wherein the salt concentration of mixture C is no more than 0.5% of total dissolved salt (5000 ppm).

90. The method according to items 1-89, wherein the salt concentration of mixture C is less than 5 g/L of total dissolved salt).

91. The method according to items 1-90, wherein mixture C comprises water, salts including NaCI and/or other remaining ionic salts and polar molecules, amine based on formula (I), and related ammonium salts based on structure from formula (I).

92. The method according to items 1-91 , wherein the contacting in step i) is done by mixing, shaking, adding, slurring, or injecting diamine based on the formula (I) into mixture A.

93. The method according to items 1-92, wherein the amine in mixture A is soluble, insoluble, homo- or heterogenous.

94. The method according to items 1-93, wherein the CO2 concentration is from 4 ppm to 1000 ppm.

95. The method according to items 1-94, wherein the CO2 concentration is 2000 ppm to 100000 ppm.

96. The method according to items 1-95, wherein the CO2 is gaseous, liquid or solid, and wherein the CO2 is in the form of CO2 HCO3 or C03 ² when it reacts with the amine.

97. The method according to items 1-96, wherein the CO2 is drawn from atmospheric air .

98. The method according to items 1-96, wherein the CO2 is added to the reaction in a blowing process of adding CO2, for example from a CO2 tank or from exhaled breath.

99. The method according to items 1-96, wherein the sufficient time period in step (ii) is 5 seconds to 15 minutes 100. The method according to items 1 -99, wherein the precipitate Z comprises organic diamines based on formula (l)comprising carbon dioxide, salts and polar substances, which originated from mixture A.

101. The method according to items 1 -100, wherein the precipitate Z is a mixture of the diamine, the diamine-C0 ₂ adducts, the diamine-salt complex, diamine-based ammonium salts of bicarbonate, carbonated, and sodium chloride.

102. The method according to items 1 -101 , wherein the precipitate is separated by filtration, gravimetrical separation, centrifugation or decantation.

103. The method according to items 1 -102, wherein the method is conducted at room temperature.

104. The method according to items 1 -103, wherein the method is conducted at minimum 20°C.

105. The method according to items 1 -104, wherein the method is conducted at 10-45°C.

106. The method according to items 1 -105, wherein formula (l):M ^a++X ^b - co-precipitate is in an about 1 : 1 - 5: 1 molar ratio, preferably 1 :1 ratio to reduce the amount of used formula (I) per one desalination cycle.

107. The method according to items 1 -106, wherein the method is performed on an industrial scale, such as from 1 L to 100.000 L.

108. An amine selected from the group consisting of:

109. One or more of the amines according to item 108, for use in a method of desalination according to claims 1-107.

110. Method of immobilising an amine of formula (I) on a solid support polymer based on the formula (I) comprising the step of: wherein the synthesis of polymer-supported diamine is performed by using a general

polymerization procedure wherein the diamine, styrene, 1 ,4-divinylbenzene (0-10 mol%) and radical initiator (0-10 mol%) is mixed in water or organic solvent, or water-organic solvents mixture, and stirred at elevated temperature for extended time, and wherein the obtained polymer is washed with relevant organic solvent and water to removed unreacted residue and smaller molecular weight polymers to afford desired diamine-functionalized polymers, or

wherein the synthesis of alkylchain modified polyethylene imine is performed by reacting PEI (polyethyleneimine) with an alkyl halide in water or organic solvent, or water-organic solvents mixture, and stirred at elevated temperature for extended time, and wherein the obtained polymer is washed with relevant organic solvent and water to removed unreacted residue and smaller molecular weight polymers to afford desired diamine-functionalized polymers. 11 1. The solid-state polymer produced from the method of item 1 10.

112. Method of CO2 scrubbing comprising the steps; i) contacting an amine of formula (I) with an aqueous solution comprising a salt of formula M ^a+X ^b (mixture A) to generate an aqueous mixture comprising amine and salt (mixture B), ii) contacting mixture B with CO2 for a sufficient time period to co-precipitate with the amine of formula (I), M ^a+, and X ^b to generate a precipitate (Z), and iii) isolate the precipitate (Z) comprising CCte to obtain an aqueous mixture C of lower salinity than aqueous mixture (A), wherein the amine formula (I) is defined by:

Formula (I) wherein,

Ri , R2 and R3 is selected independently from H, Me, Et, n-Pr, i-Pr, n-Bu, i-Bu, t-Bu, Ph, Benzyl, and Aryl

X is selected from C=0, C=NH, C=S, CHF, CFI2 and CF2.

R4 and R5 is selected independently from CFI3, FI and F n is an integer from 1 -4 included m is an integer from 3-18 included, and wherein

⁺M _a is a cation ⁺M with a indicating the number of cations in the salt, and

^"Xb is an anion X with b indicating the number of anions in the salt. 1 13. A method for CO2 complexation, CC>2-capture and/or CO2 sequestration comprising the steps; i) contacting an amine of formula (I) with an aqueous solution comprising a salt of formula M ^a+X ^b (mixture A) to generate an aqueous mixture comprising amine and salt (mixture B), ii) contacting mixture B with CO2 for a sufficient time period to co-precipitate with the amine of formula (I), M ^a+, and X ^b to generate a precipitate (Z), and iii) isolate the precipitate (Z) comprising CCte to obtain an aqueous mixture C of lower salinity than aqueous mixture (A), wherein the amine formula (I) is defined by:

Formula (I) wherein, R-i , R2 and R3 is selected independently from H, Me, Et, n-Pr, i-Pr, n-Bu, i-Bu, t-Bu, Ph,

Benzyl, and Aryl

X is selected from C=0, C=NH, C=S, CHF, CFI2 and CF2.

R4 and R5 is selected independently from CFI3, FI and F n is an integer from 1 -4 included m is an integer from 3-18 included, and wherein

⁺M _a is a cation ⁺M with a indicating the number of cations in the salt, and "Xb is an anion X with b indicating the number of anions in the salt.

1 14. The method according to item 1-107, 1 12, or 1 13, wherein the residual amine from mixture C is further reduced by applying ion exchange resin or microfiltration.

1 15. The method according to item 1-107, 1 12, or 1 13, wherein the residual amine from mixture C is further reduced by applying low temperature to increase precipitation rate, or to induce phase separation. 1 16. The method according to item 1-107, 1 12, or 1 13, wherein the mixture C is diluted with fresh water with low salinity level, to provide maximum volume of drinkable water (potable water) using desalinated mixture C.

1 17. The method according to item 1-107, 1 12, or 1 13, wherein the salinity level of mixture C reaches drinkable water by applying subsequent desalination.

1 18. The method according to item 1 17, wherein the subsequent steps comprise steps i) to iii) of claim 1.

1 19. The method according to item 1-107, 1 12, or 1 13, wherein the precipitate Z is dissolved or dispersed in organic solvent(s) to precipitate salts out of the used organic solvents upon heating the system using mild heat (30 - 80°C) source or waste heat.

120. The method according to item 1 19, wherein the organic solvent is water and the heating of Z is done by sunlight.

121. The method according to items 1 19-120, wherein after precipitation of salts, the diamine formula (I) is recovered by evaporating the used organic solvents.

122. The method according to item 1-107, 1 12, or 1 13, wherein precipitate Z is formed applying ambient or low temperature in a range of 0 - 20 °C to increase precipitation rate, and/or to induce phase separation.

123. The method according to any one of items 1-122, further comprising one or more steps of membrane distillation desalination and/or reverse osmosis desalination.

124. The method according to item 123, wherein the further one or more steps are included in before or after contacting of the amine of formula (I) with mixture A.

125. A kit for desalination comprising a compound of formula (I) as defined in any of the previous claims and means for separating precipitate Z from the aqueous solution.

126. The kit according to item 125, further comprising a compound with a purpose of colour indication upon desalination.

127. The kit according to items 125-126, further comprising one or more disinfectants.

128. The kit according to items 125-127, further comprising iodine.

129. The kit according to items 125-128, further comprising sugar and/or other carbohydrates.

130. The kit according to items 125-129, herein the kit is an emergency kit. 131. The kit according to items 125-130, herein the kit is portable.

Previous Patent: ADJUSTING DEVICE AND METHOD FOR CONTROLLING AN EXIT THICKNESS OF A NOZZLE EXIT GAP OF A FLAT FILM MA...

Next Patent: SPAR STRUCTURE WITH INTEGRATED DOWN CONDUCTOR ELEMENT FOR LIGHTNING PROTECTION SYSTEM