CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to, and the benefit of, U.S. Provisional Application No. 63/288,779, filed on 13 December 2021, and U.S. Provisional Application No. 63/288,898 filed on 13 December 2021.

Each of the aforementioned applications is incorporated by reference herein in its entirety, and each is hereby expressly made a part of this specification.

TECHNICAL FIELD

The disclosure relates generally to systems and methods for processing fluids, and more particularly to systems and methods for removing ions from such fluids.

BACKGROUND

Deionization of liquids such as water involves the removal of ions, both cations and anions. Systems and method for removing ions from fluids are desired.

In a liquid such as water, cations may include sodium, calcium, and the like. Anions may include chloride, bromide, and the like. Deionized water is purified from most ions, but may still contain ionic impurities such as HsO and OH'. Deionized liquids such as water have extensive applications in industrial processes such as pharmaceutical production, semiconductor production, scientific experimentation, as well as cleaning and cooling. In addition, the removal of ions contained in impure water is an important step in the production of drinking water.

As the world's population increases, and water sources become scarcer and more polluted, we have recently looked to the sea for an abundant supply of water. Unfortunately, the removal of salt and other impurities from sea water or brackish water is an energy intensive process that is best suited to large commercial desalination facilities such as multistage flash evaporation plants, reverse osmosis plants, and other similar processes.

There currently exists a need for a system to remove impurities from sea water to make it fit for human consumption without the need for massive energy consumption and its associated pollution, carbon emissions, and other environmental impacts. It is expected that this need will continue to increase with the rise in world populations and the increase in global temperatures and associated water shortages.

Improvement is desired including for reducing energy consumption, capital costs, maintenance requirements, and operational complexity.

Acid Mine Drainage (AMD) is considered to be the second largest global environmental problem after climate change (UN). The main cause of AMD is due to metal sulfide by-product unearthed during mining operations.

Although there are many metal sulfide complexes, an exemplary problem metal sulfide is FeS2 (pyrite, iron sulfide) found in large amounts in metal ore mines. The FeS2 is primarily oxidized through the metabolic activity of several species belonging to the bacteria class Acidithiobacillia in the presence of water and oxygen, the process producing Fe ions (Fe ²⁺ and Fe ³⁺ ) along with SO ’ and H ⁺ , i.e. sulfuric acid. The resultant AMD wastewater is produced either naturally over a long time interval (such as in a mine tailings pond), or in a shorter time interval through artificial oxygenation as in mine run-of-plant. The end pH of such AMD wastewater or liquor, is usually below 3 and as low as -3 and can contain both ferrous Fe ²⁺ ions and ferric Fe ³⁺ ions, or it can contain only ferrous Fe ²⁺ ions if all the ferric Fe ³⁺ ions have been consumed in the oxidation of

FeS2. This as per the below three simplified reactions if pH is below 3:

1. 2FeS ₂ + 7O ₂ + 2H ₂ O 2Fe ²⁺ + 4SO ’ + 4H ⁺

2. 2Fe ²⁺ + /2O2 + 2H ⁺ 2Fe ³⁺ + H ₂ O

3. FeS ₂ + 14Fe ³⁺ + 8H2O 15Fe ²⁺ + 2SO ’ + 16H ⁺

The neutralization of AMD wastewater involves the removal of ions, both cations and anions. This is currently performed at great cost through the introduction of lime to provide for a chemical reaction that increases the wastewater pH to a desired level. After the removal of resultant solids, the neutralized liquid can be safely discharged into the environment.

Accordingly, there is a need for a system to neutralize AMD wastewater to make it fit for environmental discharge without the need for a large energy consumption (and its associated pollution, carbon emissions, and other environmental impacts), and at lower cost than through current chemical treatment methods. It is expected that this need will continue to increase with the mining of lower iron ore grades containing increased levels of FeS2. Improvement is desired including for reducing energy consumption, capital costs, maintenance requirements, operational complexity, and environmental impact.

SUMMARY

In an aspect, the disclosure describes a system to remove ions from the fluid. The system also includes a reservoir for holding a fluid; a porous medium for receiving the fluid at a predetermined pressure from the reservoir to draw the fluid through the porous medium to retain an adhered portion of the fluid at a wetting surface of the porous medium, and an electrical conductor operable to generate an electromagnetic (e.g. electrostatic) field drawing the adhered portion away from the wetting surface so as to discharge an ion-rich fluid from the wetting surface.

In an aspect, the disclosure describes a method of removing ions from a fluid held in a reservoir. The method of removing ions also includes receiving the fluid from the reservoir at a predetermined pressure; drawing the fluid through a porous medium so as to retain an adhered portion of the fluid at a wetting surface of the porous medium while keeping the adhered portion in fluid communication with the fluid in the reservoir, and generating an electromagnetic (e.g. electrostatic) field to draw the adhered portion away from the wetting surface so as to discharge an ion-rich fluid from the wetting surface.

In an aspect, the disclosure describes a system for processing a fluid to remove ions from the fluid. The system also includes a reservoir for holding the fluid; a plurality of electrical conductors comprising a first set of electrical conductors energized with a first electric polarity, and a second set of electrical conductors energized with a second electric polarity different than the first polarity. The system also includes a droplet generator in fluid communication with the reservoir and positioned to generate droplets moving towards the plurality of electrical conductors when the plurality of electrical conductors are energized, the first set of electrical conductors drawing droplets having more anions than cations, and the second set of electrical conductors drawing droplets having more cations than anions. In some embodiments, the first set of conductors is spaced apart from and interleaved with the second set of conductors. In some embodiments, wherein each conductor of the plurality of conductors is a linear wire.

In an aspect, the disclosure describes a method of treating acid mine drainage (AMD) composed of ferrous ions and sulfate ions. The method also include generating hydrogen from the AMD by deprotonation of the AMD in an electrochemical cell; using the hydrogen to generate electricity; using the electricity to cause an electromotive force in the electrochemical cell; drawing ferrous ions and sulfate ions out of the AMD after the deprotonation using a system for removing ions as described previously or elsewhere in this disclosure; and forming a salt by reacting the ferrous ions with the sulfate ions.

Embodiments can include combinations of the above features.

Further details of these and other aspects of the subject matter of this application will be apparent from the detailed description included below and the drawings.

DESCRIPTION OF THE DRAWINGS

Reference is now made to the accompanying drawings, in which:

FIG. 1 is a schematic representation of a system to remove ions from the fluid, in accordance with an embodiment;

FIG. 2 is a schematic representation of a system for deionization of fluid, in accordance with an embodiment;

FIG. 3 is a schematic of system for processing an acid liquid via deprotonation and electrostatic deionization, in accordance with an embodiment;

FIG. 4 is a perspective view of a system for desalinating seawater, in accordance with an embodiment;

FIG. 5 is a graphic depiction of a parallel three-stack electrostatic ion sieve desalination/deionization system, in accordance with an embodiment;

FIG. 6 is flow chart of a method of removing ions from a fluid held in a reservoir, in accordance with an embodiment; and

FIG. 7 illustrates a block diagram of a computing device, in accordance with an embodiment.

DETAILED DESCRIPTION

A deionization system is described that comprises a fluid reservoir containing a liquid in fluid communication with a droplet generating substrate, a droplet generating substrate for releasing liquid through an electrostatic induction structure, an electric potential between said induction structure and a reference, and a tank for receiving the liquid. The liquid received in the tank may have an increased ionic content versus the liquid originating in the fluid reservoir due to electrostatic ion concentration at the droplet generating substrate interface. There is further described a deprotonation and deionization system and method comprising a fluid reservoir containing an acid mine drainage (AMD) liquor. The fluid reservoir acts as an electrolytic cell due to the presence a sacrificial anode that is electrically coupled to an inert cathode, both immersed in the AMD liquor. As a result, deprotonation may occur via the introduction of cations from the sacrificial anode (oxidation), along with the removal of protons at the inert cathode (reduction), with the resultant generation of hydrogen gas. The released hydrogen gas may be captured and used to increase the above process rate, e.g. in an environmentally friendly manner, or may be captured, stored and sold. The above process may serve to neutralize the AMD liquor by raising its pH to just below 7, however, the AMD liquor may still contain metal cations (both native from the original wastewater and those added in from the sacrificial anode). It may also still contain complementary sulfate anions. To effect deionization and removal of these complementary cations and anions, the fluid reservoir is in fluid communication with a droplet generating substrate for releasing liquid through an electrostatic induction structure, and having an electric potential applied between said induction structure and a reference, and having a tank for receiving the liquid. The liquid received in the tank may have an increased ionic content versus the liquid originating in the fluid reservoir due to electrostatic ion concentration at the droplet generating substrate interface. The liquid remaining in the fluid reservoir may have a pH close to 7 due to the deprotonation and will be substantially devoid of metal and sulfate ions, and may be safely discharged into the environment. The liquid in the second fluid reservoir may also have a pH close to 7, but contains a concentrated level of the metal and sulfate ions, and this may be further processed, e.g. to crystallize and extract metal hydroxide solid that has commercial value.

Aspects of various embodiments are described in relation to the figures.

FIG. 1 is a schematic representation of a system 100 to remove ions from the fluid, in accordance with an embodiment.

A reservoir 103 may hold the fluid. A porous medium 117 receives the fluid at a predetermined pressure to draw the fluid through the porous medium 117 to retain an adhered portion 113 of the fluid at a wetting surface 130 of the porous medium 117. In various embodiments, a predetermined pressure may refer to a range or a plurality of pressures.

Some embodiments may include the use of a closed vessel filled with fluid that has insufficient head and pumps to pressurize the vessel. For example, such configurations may be used together with or instead of the porous medium. An electrical conductor 125 may be operable to generate an electrostatic field 115 drawing the adhered portion 113 away from the wetting surface 130 so as to discharge an ion-rich fluid 112 from the wetting surface 130.

The reservoir 103 may be positioned at least partially above the porous medium 117 to cause gravity-assisted flow of the fluid from the reservoir 103 to the porous medium 117, or (in some embodiments) via a pump and closed vessel.

The porous medium 117 may be positioned at least partially above the electrical conductor 125 to cause gravity-assisted flow of the ion-rich fluid 112 discharged from the wetting surface 130, and to receive the fluid, from the reservoir 103, at a receiving surface of the porous medium 117 that is vertically higher than the wetting surface 130.

The fluid may traverse a width of the porous medium 117 to reach the wetting surface 130. In various embodiments, at least one of the width and a porosity of the porous medium 117 may be configured based on the predetermined pressure so as to retain the adhered portion 113 on the wetting surface 130 when the electrostatic field 115 is not drawing the adhered portion 113 portion down. In some embodiments, pressurized air or air pressure may be admitted underneath the porous medium to balance flow.

In various embodiments, at least one pump and/or valve may be operable to control a fill level of the reservoir 103 to control hydrostatic pressure by at least one of drawing in liquid feedstock into the reservoir 103 and discharging the fluid from the reservoir 103.

In the following reference numerals are referenced to the figures so that analogous parts are labelled with reference numerals having in common their last two digits. For example, the reservoir 103 may be referred to as reservoir 203 and reservoir 303 in, respectively, in FIGS. 2 and FIG. 3.

FIG. 2 is a schematic representation of a system 200 for deionization of fluid, in accordance with an embodiment.

As referred to herein, deionization (and desalination) may include a partial removal of ions from a fluid. For example, a plurality of systems may be needed to remove all the ions.

The system 200 may include a single-stream electrostatic ion sieve. Stream, as used herein, may refer to either a stream of fluid (such as water), or a series of water droplets, or a stream of partially continuous water droplets. For clarity, mechanical and structural supports are not shown. For example, the intake 201 may draw in seawater or brackish water through a pipe or conduit (feedwater), which may be in fluid communication with a main source or reservoir (not shown).

Filtering and other pre-treatment (also not shown) appropriate for the fluid source (water source) being used may also be incorporated into the intake 201. Fluid travel may be facilitated by way of a pump 202A, which may be a low pressure feed pump, connected to a reservoir inlet for drawing liquid feedstock into the reservoir 203. The pump 202A may be operably coupled to a controller 207 (or control system) so as to be controlled by the controller 207. The feed pump 202A may serve to fill and maintain the feedwater reservoir 203 (e.g. tank). The reservoir 203 may hold the fluid at a fill level of fluid 204 in the reservoir 203, e.g. as determined by a fill level sensor 205A. The fill level sensor 205A may be configured to sense the fill level of the reservoir 203 to generate an indicator thereof. The fill level sensor 205A may be operably connect to or operably coupled to the controller 207 and one or more pumps 202A, 202B, 202C so as to facilitate feedback control via the controller 207 of such pumps, based on the indicator and the predetermined pressure.

FIG. 2 is now described using seawater as an example liquid feedstock being supplied thereto via, the system 200 then being used for desalination of the seawater.

The bottom of feedwater reservoir 203 is in liquid communication with the top of a porous medium 217, which may be a porous sieve matrix. The porous medium 217 may be suitable to receive the fluid at a predetermined pressure, e.g. a hydrostatic pressure, to draw the fluid through therethrough at a receiving surface 231 of the porous medium 217. As in the embodiment of FIG. 2, in various embodiments, the reservoir 203 may be positioned at least partially above the porous medium 217 to cause gravity-assisted flow of the fluid to the porous medium 217.

In some embodiments, it is found that it is particularly advantageous to use a ceramic, plastic or composite material or the like to form the porous medium 217. In general, it is found that materials with a dielectric constant greater than 1 are particularly advantageous. The pore structure, geometric dimensions, and other properties of the porous medium 217 are adapted such that when the tank is filled to a predetermined fill level (e.g. any fill level between the reservoir 203 being approximately one-third full and full), very little liquid will naturally pass through the porous medium 217 (reservoir 203 may be at very low pressure), e.g. due to the surface tension of the seawater. An adhered portion of the fluid is then retained at a wetting surface 230 of the porous medium 217. For example, it is found then that an enormous multitude of seawater droplets 226 form on the underside of the porous medium 217 and are retained thereon at a wetting surface 230 of the porous medium, e.g. due to the action of their surface tension (at least partially an electrostatic phenomena). The receiving surface 231 is vertically higher than the wetting surface 230. It is understood that the total pressure drop across a porous medium is a function of a variety of factors such as porosity, material type, and dimensions. Such factors may be adapted so as to achieve a pressure drop, from a reference hydrostatic pressure of the reservoir 203 (which is predetermined based on the predetermined fdl level), that causes formation of an adhered portion of the seawater at the wetting surface 230.

Below the porous medium 217 there may be located or positioned a tank 211 (permeate, reject, or concentrate tank) for receiving ion-rich fluid 212 (or permeate liquid) that may permeate through the porous medium 217. Unlike reverse osmosis systems where the "permeate" is the recovered drinking water, the "permeate" that passes through porous medium 217 is the reject or concentrate (e.g. brine) in this deionization (e.g. desalination) system, i.e. the ion-rich fluid 212 has more ions than the liquid feedstock that is fed into the reservoir 203. The electrical conductors 225 is positioned above the tank 211 to allow the ion-rich fluid 212 to discharge from the wetting surface 230 to fall into the tank 211.

An array or grid of electrical conductors 225 (e.g. electrically conductive wires), spaced at an appropriate distance from each other, are positioned in the vicinity of the wetting surface 230 and suitably spaced apart from the wetting surface 230. For example, these may be located below the bottom surface of the porous medium and above the upper surface of the ion-rich fluid 212. The porous medium 217 may be positioned at least partially above the electrical conductors 225 to cause gravity-assisted flow of the ion-rich fluid 212 discharged from the wetting surface 230 and to receive the fluid from the reservoir 203.

In various embodiments, conductor spacing may be in the range of 5 to 10 mm, conductor to surface may be 5 to 25 mm.

The electrical conductors 225 may be dielectrically coated (insulated) to reduce electric charge leakage or charge transfer and corona effects. The electrical conductors 225 may be referred to as the electrostatic induction or draw grid. The electrical conductors 225 may be energized to high voltages of alternating polarity from controller 207. The high voltages may be static or of varying potential and/or of varying polarity over time.

Energization of the electrical conductors 225, e.g. by operation by the controller 207, draws the adhered portion of the fluid away from the wetting surface 230. A first set of electrical conductors of the electrical conductors 225 may be energized with a first electric polarity so as to draw more cations than anions out of the fluid 204. A second set of electrical conductors may be energized with a second electric polarity different than the first polarity so as to draw more anions than cations out of the fluid 204. In various embodiments, such sets of electrical conductors may form a grid as described previously, e.g. the first set of electrical conductors may be spaced apart from and interleaved with the second set of electrical conductors.

The tank 211 may be connected to pump 202B, which may be operably coupled to the controller 207 to be driven by the controller 207. The pump 202B may be a reject pump and may be in fluid communication with the tank 211.

The pump 202B may feed reject permeate (the ion-rich fluid 212) to a brine disposal area and/or a holding tank, neither of which is shown in FIG. 2. The level of ion-rich fluid 212 in the tank 211 may be controlled in feedback based on input from a level sensor 205B to the controller 207. The input may be an indicator of a level of ion-rich fluid 212 in the tank 211.

The rightmost end of the reservoir 203 is connected to a discharge tank 224 (or freshwater holding tank) to received fluid being discharged from the reservoir 203. The discharged fluid in the discharge tank 224 may be pumped out as desired via a pump 202C. In some embodiments, pump 202C may be connected to a reservoir outlet to discharge the fluid 204 from the reservoir 203. The pump 202C may be operably coupled to the controller 207 to be driven by controller 207. The output 218 of the pump 202C may feed a drinking water system or reservoir. A level of the discharged fluid 223 in the discharge tank 224 (or discharge fluid level or freshwater liquid level) may be controlled by the controller 207 based on an indicator of the level from a level sensor 205C. Discharge sensor(s) may be disposed in the discharge tank 224 and immersed in the discharged fluid 223. Such discharge sensor(s) may be suitable to generate an indicator of ionic content of the discharged fluid. The controller 207 may control pumps and/or valves based on such an indicator.

In various embodiments, advantageously, the pumps 202A, 202B, 202C may be of low or extremely low pressure (but high volume). For example, in some embodiments, high pressure pumps exceeding 1000 psi may not be required or other high pressure pumps of the type used in reverse osmosis systems. It is understood that, in some embodiments, a single pump, two pumps, or more than three pumps may be used in place of the pumps 202A, 202B, 202C. As shown, there is also an ionic conductivity sensor 222 may be connected to controller 207 for monitoring the ionic content of the "product" freshwater. The ionic conductivity sensor 222 may be an example of a discharge sensor.

As described previously, in some embodiments, in normal operation, seawater droplets 226 form on the wetting surface 230 (e.g. underside surface) of the porous medium 217. It is conceived that such droplets may be retained thereon due to surface tension. For example, the droplets may be protruding or hanging from the wetting surface 230 of the porous medium 217. As the seawater droplets 226 may contain substantially similar numbers of anions and cations, the fluid in the reservoir 203 and the porous medium 217 may stay in equilibrium, until the electrical conductors 225 are energized, whereupon an electrostatic field is generated causing the droplets 226 to fall.

For example, electrostatic force may be exerted by the electrical conductors 225 onto the charges (ions) within the water droplets 226, which may lead to distinct effects. Protruding or hanging water droplets near a positive draw grid potential may have their internal ion balance altered to contain a greater majority of negative ions than positive ions (but still containing both species). Protruding or hanging water droplets near a negative draw grid potential may have their internal ion balance altered to contain a greater majority of positive ions than negative ions (but they will also still contain both species). Both the above may be referred to as (electrostatic) induction or (electrostatically) inductive. Thirdly, the surface tension of the seawater droplets 226 may be altered such that they detach themselves rapidly from the wetting surface 230 of the porous medium 217 and then fall past or upon the electrical conductors 225.

In various embodiments, the draw grid wires may be dielectrically insulated. This may be advantageous, e.g. by reducing or mitigating charge leakage or transfer from the draw grid to the water droplets to allow the droplets to end up falling into the tank 211 as the ion-rich fluid 212. In some embodiments, it has been observed that seawater droplets may appear as rain falling from the underside of the porous medium 217 into the tank 211.

In some embodiments, a substantially equal number of positive and negative ions are transported or migrated from the fluid 204 via the droplets 226. In some embodiments, as a result, there is no charge imbalance that occurs in the reservoir 203 (feedwater tank). Advantageously, this mitigates building up a potential difference between the reservoir 203 and the tank 211 (permeate tank). In some embodiments, there is balanced removal of ions from the fluid 204 to the ion-rich fluid 212 using electrostatic generator action. The electrical potential of the electrically conductive fluid in the reservoir may be at neutral or zero electrical potential with respect to the energizing high voltages originating from the controller 207 (or control system) and fed to electrical conductors 225.

FIG. 3 is a schematic of system 300 for processing an acid liquid via deprotonation and electrostatic deionization, in accordance with an embodiment.

The system 300 may allow electrochemical neutralization of an acid liquor via deprotonation, and electrostatic deionization of an acid liquor via selective ion removal, in particular but not limited to acid mine drainage wastewater. The deprotonation and deionization system and method are described below in reference to FIG. 3 may use FeS2 acid mine drainage wastewater as an example application. It should be noted, however, that other liquids that require deprotonation and deionization may also be used with the embodiments as described and contemplated herein. The deprotonation and deionization of FeS2, acid mine drainage wastewater may have a tremendous impact and benefit to the environment.

Referring to FIG. 3, there is shown a schematic representation of an acid mine drainage wastewater deprotonation and deionization system in accordance with an embodiment. For clarity, mechanical and structural supports are not shown.

The liquid feedstock (acid mine drainage liquor) or wastewater may be transferred via a low pressure feed pump 302A into a reservoir 303 (here, a fluid tank). Filtering and other pre-treatment (also not shown) appropriate for the acid mine drainage wastewater source being used may have been previously performed on the liquid feedstock. Specifically as shown in the case of FeS2 acid mine drainage liquor, the fluid 304 in the reservoir 303 may have varying pH throughout the process, and may be substantially devoid of Fe ³⁺ ions. The fluid 304 may primarily comprise water (H2O), but may be a dilute sulfuric acid solution due to an excess of protons. The fluid may also contain a minor number of OH- anions, and may contain a large number of SO4 ² ' (sulfate) anions and a large number of Fe ²⁺ (ferrous) cations. The fluid 304 may be in electrostatic equilibrium.

As shown in FIG. 3, scrap metallic iron may be fed into hopper 320 and held inside a porous holder made of inert material (stainless, graphite or the like) immersed in the fluid 304 for holding the anode 340 (i.e. the scrap Fe). In various embodiments, the anode 340 may be scrap Fe and may be non-rigid. In various embodiments, the anode 340 may be held together in the fluid 304 by the porous holder. Accordingly the scrap iron may be in electrical communication with the fluid 304 within the reservoir 303 creating a sacrificial electrode (anode 340). The anode 340 may be suitable for generating cations to be removed by the porous medium 317. Located within the reservoir 303 and in electrical communication with the fluid 304, may be an inert cathode 370, comprised of stainless, graphite or the like. Electrical communication between the anode 340 and the cathode 370 via the fluid 304 may be established.

In various embodiments, the porous holder may be a basket for holding bulk iron (Fe) or a pierced bowl shape for Iron (Fe) powder.

Electrical conductor 396 may electrically connect the cathode 370 to the anode 340 and may be external to the reservoir 303. As will be described further, the cathode 370 and anode 340 are immersed in the fluid 304 in the reservoir 303 so as to form an electrochemical cell to neutralize the fluid 304. The fluid being acidic, neutralization generates hydrogen at the cathode 370. As referred to herein, electrical conductor 396 may refer to a plurality of conductors or conductors connected via intermediate components, such as a power converter and/or circuitry 364 shown in

FIG. 3

In various embodiments, the system 300 may include circuitry coupling the electrical generator 342 to the cathode 370 and the anode 340 to mitigate, using the electricity, toss of electrochemical potential of the electrochemical cell as the fluid is neutralized.

In various embodiments, the circuitry 364 may be in the form of a power converter, e.g. a boost converter. In various embodiments, the anode 340 may be electrically externally connected to the positive terminal of the power converter (or circuitry 364), e.g. a boost converter. The inert cathode 370, comprised of stainless, graphite or the like, and that may be electrically connected to the negative terminal of the converter (or circuitry 364).

A hydrogen gas collection shroud 390 may collect hydrogen gas and conduct collected hydrogen gas to a valve to be admitted to an electrical generator 342 to generate electricity using the hydrogen. In some embodiments, the electrical generator 342 is a fuel cell. In some embodiments, the electrical generator 342 may include a gas generator configured to generate shaft power using hydrogen gas to generate electricity. Also shown, ambient air may be drawn through intake filter 362, by the action of the suction blower 382 be admitted to the electrical generator 342. In various embodiments, purified or separated air may be drawn in, e.g. purified oxygen may be drawn suitable for use in the fuel cell and/or a hydrogen combustion chamber. The negative terminal and the positive terminal of the electrical generator 342 may be connected to the circuitry 364. The exhaust output (liquid water) of the electrical generator 342 may be connected to a holding tank 332A, which as shown, is led to valve to be admitted to the reservoir 303 for admixture into the fluid 304 if desired or necessary as makeup water.

Assuming fresh fluid 304 in the reservoir 303, fresh scrap Fe at the anode 340 (an electrode) and zero hydrogen gas at the cathode 370 (an electrode), the electrical generator 342 may be offline. As such, the circuitry 364 may internally electrically connect its positive and negative electrode terminals together, effectively providing a short circuit therebetween. As a result, there may be seen an electrochemical potential. In some embodiments, an electrochemical potential of approximately 0.67V between the sacrificial anode 340 and the inert cathode 370 may be seen. This electrochemical potential may serve to drive electrons from the anode 340 (as Fe is oxidized into solution as Fe ²⁺ ). The stripped electrons may travel from the anode 340 to the cathode 370, where they may reduce H ⁺ (protons) out of solution as hydrogen gas. This deprotonation process serves to raise the pH of fluid 304, i.e. cause some amount of neutralization of the fluid 304, which may occur at the base electrolytic rate due to the 0.67V potential. This potential towers as pH rises, stowing the rate. If some of the fluid 304 is continuously removed from the reservoir 303 along with selected ions, then by continually admitting fresh wastewater of tower pH, then the pH of the fluid 304 may be maintained around 6.5 or less. Further, as shown, as the deprotonation continues, there may be hydrogen gas available to the electrical generator 342. The electrical generator 342 may come online and feed electrical energy to the circuitry 364.

In various embodiments, the circuitry 364 may be able to boost the electrolytic cell potential of 0.67V to a higher potential due to the electrical energy delivered by the electrical generator 342. This may serve to increase the electrolytic reaction rate and increase the rate of Fe oxidation, and the rate of deprotonation overall.

In some embodiments, the maximum boosted potential between the anode 340 and the cathode 370 may be just below the dissociation potential of water, i.e. around 1.22V.

As mentioned previously, the fluid 304 may be continuously withdrawn along with selected ion species, this being accomplished via electrostatic means using a system for removing ions as described previously in reference to FIG. 2.

As described previously in reference to FIG. 2, the bottom of the reservoir 303 in FIG. 3 may be in fluid communication with the top of a porous sieve matrix or porous medium 317. The porous medium 317 may configured such that at a predetermined fill level and/or pressure (e.g. hydrostatic pressure caused by the fill level), very little liquid will naturally pass through the porous medium 317 (the reservoir 303 may be at very low pressure or atmospheric pressure) An enormous multitude of wastewater droplets 326 may form on the underside (wetting surface 330) of the porous medium 317 and be retained there until acted upon by an electrostatic field. For example, it is thought that this may occur due to the action of their surface tension which is an electrostatic phenomenon, as described previously.

Below the porous medium 317 there is located a tank 311 for receiving ion-rich fluid 312 that may permeate through porous medium 317.

Located just below the bottom surface of the porous medium 317, and above the upper surface of the permeate liquid (ion-rich fluid 312), is an array or grid of electrical conductors 325 (such as electrically conductive wires), which may be spaced at an appropriate distance from each other and from the underside of the porous medium 317. The draw grid wires may be energized to high voltages of alternating polarity from a high voltage generator, HVG 389.

Hydrated Fe ²⁺ 100 ions and hydrated SOi ^2- ions may be drawn out of the fluid 304 in the reservoir 303 and pulled down into tank 311 as ion-rich fluid 312. The tank 311 may allow reaction of the anions and the cations drawn out of the fluid 304 into the tank 311 via the porous medium 317 to form a salt. The salt may be Iron(II) sulfate. The ion-rich fluid 312 may be concentrated ferrous sulfate in solution at a pH of about 6.5. The ion-rich fluid 312 may be seen to be fed to pump 302B and then to a crystallizer 380 via a valve to receive the salt to form crystallized salt. The crystallizer 380 may incorporate a stirrer driven by motor 392, and may heat its contents under a vacuum from vacuum blower 394. Water vapour may be formed from the exhaust therefrom.

A crystallizer 380 may further ion-rich fluid 312 from tank 311 so as to force FeSCL crystal solid formation. Crystallizer 380 may feed its output via pump 302C to centrifugal separator 360. The output of the separator 360 is discharged as solid end product FeSCk 7H2O.

The discharge water from separator 360 may be fed to a holding tank 332B and may now have a pH very close to seven. The holding tank 332B may feed its contents via pump 302D back to the reservoir 303 as makeup water, or it may be discharged safely into the environment.

In various embodiments, systems similar to the system 300 may be used for deprotonation and processing of other metal sulfide AMD liquors, and also to Alkaline Mine Drainage liquors through inverse substitution of feed metal and charge transport in order to effect protonation. As described, the numerous pumps, valves, sensors may be controlled and interrogated by a controller 307 (e.g. a microcontroller or microprocessor) under software and algorithmic control. In various embodiments, the controller 307 may be configured to receive sensed data indicative of pH, temperature, flow rates, and voltage (of the electrical generator or the fuel cell). In various embodiments, the controller 307 may be configured to control one or more pumps, one or more valves, and/or one or more high voltage generators by providing a voltage or signal thereto, and may be configured for two-way communication and control to an inverter or the converter.

FIG. 4 is a perspective view of a system 400 for desalinating seawater, in accordance with an embodiment.

The graphic depiction shows a single electrostatic ion sieve as used in a desalination/deionization system.

Fluid 404 is disposed in a reservoir 403 and exposed to a porous medium 417, e.g. a porous medium, to allow permeation of the fluid 404 into a tank 411 as ion-rich fluid 412 by application of an electrostatic field. As ions are removed from the fluid 404, fluid is discharged into a discharge tank 424 of discharged fluid 423.

FIG. 5 is a graphic depiction of a parallel three-stack electrostatic ion sieve desalination/deionization system, in accordance with an embodiment.

The deionization system comprises a plurality of (sub)systems 500A, 500B, 500C, e.g. systems according to any of the preceding embodiments described.

The plurality of systems may define a plurality of reservoirs in serial fluid communication so as to facilitate serial deionization of fluid.

The plurality of reservoirs may be vertically stacked so as to allow gravity-assisted flow of the fluid from one reservoir to another.

The first system 500A may comprise a first reservoir for holding a first fluid. A first porous medium receives the first fluid at a first predetermined pressure to draw the first fluid through the first porous medium to retain an adhered portion of the first fluid at a wetting surface of the first porous medium. A first electrical conductor of the first system 500A is operable to generate a first electrostatic field drawing the adhered portion away from the wetting surface so as to discharge a first ion-rich fluid from the wetting surface. The second system 500B may comprise a second reservoir for holding a second fluid and configured to receive the first fluid from the first reservoir, the first fluid being richer in ions than the second fluid. The second porous medium receives the second fluid at a second predetermined pressure to draw the second fluid through the second porous medium to retain an adhered portion of the second fluid at a wetting surface of the second porous medium. A second electrical conductor of the second system 500B is operable to generate a second electrostatic field drawing the adhered portion of the second fluid away from the wetting surface of the second porous medium so as to discharge, from the wetting surface of the second porous medium, a second ionrich fluid that is richer in ions than the second fluid. The third system 500C may be connected to the second system 500B in a similar manner.

For example, in various embodiments, each system may remove 10-20% of ions.

FIG. 6 is flow chart of a method 600 of removing ions from a fluid held in a reservoir, in accordance with an embodiment.

Step 602 of the method 600 includes receiving the fluid from the reservoir at a predetermined pressure.

Step 604 of the method 600 includes drawing the fluid through a porous medium so as to retain an adhered portion of the fluid at a wetting surface of the porous medium while keeping the adhered portion in fluid communication with the fluid in the reservoir.

Step 606 of the method 600 includes generating an electrostatic field to draw the adhered portion away from the wetting surface so as to discharge an ion-rich fluid from the wetting surface.

In some embodiments of the method 600, the reservoir is positioned at least partially above the porous medium to cause gravity-assisted flow of the fluid from the reservoir to the porous medium.

In some embodiments of the method 600, the porous medium is positioned at least partially above an electrical conductor generating the electrostatic field to cause gravity-assisted flow of the ionrich fluid discharged from the wetting surface and to receive the fluid, from the reservoir, at a receiving surface of the porous medium that is vertically higher than the wetting surface.

In some embodiments of the method 600, receiving the fluid from the reservoir at a predetermined pressure includes receiving the fluid at a receiving surface of the porous medium to cause the fluid to traverse a width of the porous medium to reach the wetting surface. At least one of the width and a porosity of the porous medium may be configured based on the predetermined pressure so as to retain the adhered portion on the wetting surface.

In some embodiments of the method 600, the electrostatic field is a first electrostatic field configured to draw more cations than anions out of the fluid.

Some embodiments of the method 600 include generating a second electrostatic field to draw the adhered portion away from the wetting surface so as to discharge the ion-rich fluid from the wetting surface. The second electrostatic field may be configured to draw more anions than cations out of the fluid.

In some embodiments of the method 600, the predetermined pressure is hydrostatic pressure based on a fill level of the reservoir.

Some embodiments of the method 600 include controlling the fill level by at least one of drawing in liquid feedstock into the reservoir and discharging the fluid from the reservoir.

Some embodiments of the method 600 include generating an indicator of the fill level; and

Some embodiments of the method 600 include controlling the fill level based on the indicator by at least one of drawing in liquid feedstock into the reservoir and discharging the fluid from the reservoir.

Some embodiments of the method 600 include discharging the fluid from the reservoir.

Some embodiments of the method 600 include receiving discharged fluid into a discharge tank.

Some embodiments of the method 600 include generate an indicator of ionic content of the discharged fluid in the discharge tank.

Some embodiments of the method 600 include controlling, based on the indicator of the ionic content, at least one of drawing in liquid feedstock into the reservoir and discharging the fluid from the reservoir.

In some embodiments of the method 600, the indicator is indicative of conductivity of the discharged fluid in the discharge tank.

Some embodiments of the method 600 include receiving the ion-rich fluid into a tank positioned beneath the wetting surface.

In some embodiments of the method 600, the fluid is seawater. In some embodiments of the method 600, the porous medium includes a plastic matrix.

In some embodiments of the method 600, the fluid is a first fluid, the ion-rich fluid is a first ionrich fluid, the reservoir is a first reservoir configured to receive a liquid feedstock that is richer in ions than the first fluid, the porous medium is a first porous medium, the predetermined pressure is a first predetermined pressure, and the electrostatic field is a first electrostatic field.

Some embodiments of the method 600 include receiving a second fluid from the first reservoir into a second reservoir at a second predetermined pressure.

Some embodiments of the method 600 include drawing the second fluid through a second porous medium so as to retain an adhered portion of the second fluid at a wetting surface of the second porous medium while keeping the adhered portion of the second fluid in fluid communication with the second fluid in the second reservoir.

Some embodiments of the method 600 include generating a second electrostatic field to draw the adhered portion of the second fluid away from the wetting surface of the second porous medium so as to discharge a second ion-rich fluid from the wetting surface of the second porous medium.

Some embodiments of the method 600 include electrically connecting a cathode and an anode, each of the cathode and the anode being immersed in the fluid in the reservoir to form an electrochemical cell to neutralize the fluid.

In some embodiments of the method 600, the fluid is acidic such that neutralization of the fluid generates hydrogen at the cathode.

Some embodiments of the method 600 include generating electricity using the hydrogen.

Some embodiments of the method 600 include using the electricity to cause an electromotive force in the electrochemical cell to mitigate loss of electrochemical potential of the electrochemical cell as the fluid is neutralized.

In some embodiments of the method 600, the electrical generator is a fuel cell coupled to an oxygen source.

In some embodiments of the method 600, using the electricity to cause the electromotive force in the electrochemical cell includes using a power converter.

In some embodiments of the method 600, the anode is a sacrificial anode that generates cations, the cations being removed from the fluid via the porous medium. Some embodiments of the method 600 include holding the anode in a porous holder immersed in the fluid while allowing electrical communication between the anode and the cathode via the fluid.

In some embodiments of the method 600, the anode is non-rigid and held together in the fluid by the porous holder.

In some embodiments of the method 600, the cathode generates anions, the electrostatic field is a first electrostatic field configured to draw more of the cations than the anions out of the fluid.

Some embodiments of the method 600 include generating a second electrostatic field to draw the adhered portion away from the wetting surface so as to discharge the ion-rich fluid from the wetting surface. The second electrostatic field may be configured to draw more of the anions than the cations out of the fluid.

Some embodiments of the method 600 include receiving the ion-rich fluid discharged from the wetting surface into a tank to allow reaction of the anions and the cations to form a salt.

In some embodiments of the method 600, the fluid comprises ferrous ions and sulfate ions.

In some embodiments of the method 600, the anode comprises iron.

In some embodiments of the method 600, the salt is Iron(II) sulfate.

In some embodiments of the method 600, the cathode is inert.

Some embodiments of the method 600 include crystallizing the salt to form crystallized salt.

FIG. 7 illustrates a block diagram of a computing device 700, in accordance with an embodiment.

As an example, the controller 207 and the controller 307, and/or associated control systems, may be implemented using the example computing device 700 of FIG. 7.

The computing device 700 may include at least one processor 702, memory 704, at least one I/O interface 706, and at least one network communication interface 708.

The processor 702 may be a microprocessor or microcontroller, a digital signal processing (DSP) processor, an integrated circuit, a field programmable gate array (FPGA), a reconfigurable processor, a programmable read-only memory (PROM), or combinations thereof.

The memory 704 may include a computer memory that is located either internally or externally such as, for example, random-access memory (RAM), read-only memory (ROM), compact disc read-only memory (CDROM), electro-optical memory, magneto-optical memory, erasable programmable read-only memory (EPROM), and electrically-erasable programmable read-only memory (EEPROM), Ferroelectric RAM (FRAM).

The I/O interface 706 may enable the computing device 700 to interconnect with one or more input devices, such as a keyboard, mouse, camera, touch screen and a microphone, or with one or more output devices such as a display screen and a speaker.

In various embodiments, the controller 207 and the controller 307 may be implemented using digital and/or analog circuits. For example, in some embodiments, it is understood that solely analog circuits may be used to implement controllers and control systems.

It is understood that any and all theories of operation set forth in the foregoing passages are not intended to be limiting or intended to bind aspects disclosed herein to those particular theories of operation but have been set forth to illustrate possible or putative modes of operation.

As can be understood, the examples described above and illustrated are intended to be exemplary only.

The embodiments described in this document provide non-limiting examples of possible implementations of the present technology. Upon review of the present disclosure, a person of ordinary skill in the art will recognize that changes may be made to the embodiments described herein without departing from the scope of the present technology. For example, deprotonation of alkaline mine drainage may be carried out using similar methods and systems as described herein. Yet further modifications could be implemented by a person of ordinary skill in the art in view of the present disclosure, which modifications would be within the scope of the present technology.

The term “connected” or "coupled to" may include both direct coupling (in which two elements that are coupled to each other contact each other) and indirect coupling (in which at least one additional element is located between the two elements).