FIELD OF THE INVENTION

The invention relates to fine particle synthesized binders comprising

thermoplastic binders with functional additives, and the use of the fine particle synthesized binder to form porous solid, block structures for the removal of contaminants from fluids. The synthesized binder can be combined with one or more adsorbents, such as activated carbon, to form a solid structure for fluid filtration. The synthesized binder of the invention result in higher levels of functional additives in the final filtration article, providing for a more efficient removal of materials from the fluid stream. In addition, use of the fine particulate synthesized binder of the invention results in better binding and retention of the functional additives - giving a final filtration article where more functional additive is retained, and less released, during filtration. In addition, the bound and retained functional additives exhibit very low fouling by the thermoplastic binder.

BACKGROUND OF THE INVENTION

Composite porous solid articles, such as porous separation articles and carbon block filtration articles, are known in the art. These articles are produced using mixtures of thermoplastic binders and adsorbent materials such as activated carbon powder. The articles preferably are formed under conditions effective to permit the thermoplastic binder to connect the adsorbent materials in discrete spots, rather than as a coating. This arrangement permits the adsorbent materials to be in direct contact, and to interact with, a liquid or gas. The resulting fine particle synthesized binder solid article is porous, permitting the liquid or gas to penetrate into and pass through the article. Such articles are especially useful in water purification, purification of organic waste streams, in biological separations, gas storage, gas separation, and catalyzed chemical reactions.

US 6,395,190 describes carbon filters and a method for making them having 15 to 25 weight percent of a polyolefin binder, where the average binder particle size is from 5 to 25 micrometers; and having activated carbon particles where the majority of the particles are in the 200-325 mesh range (44-74 micrometers).

Small particle size binder, for example emulsion polymerized poly(vinylidene fluoride) for a porous block article, has been found to improve the performance of the article by providing effective binding at lower volume loadings - which in turn leaves open more of the surface of the functional additives and /or adsorbents (like activated carbon, zeolites or ion exchange agents, etc) - providing even greater efficiency. Larger particle size binders typically used, such as polyethylene, ethylenevinyl acetate and polypropylene binders are known to foul the surface of these functional additives or adsorbents.

Examples of fine particle synthesized binder porous solid articles, as well as methods for producing them, are described for example in WO 2014/055473 and WO 2014/182861, the entire disclosures of each of which are incorporated herein by reference for all purposes. These articles use polyvinylidene fluoride or polyamide binders, rather than the polyethylene binders previously used for carbon block filtration articles.

In some applications, it is desired to add additional functionality to the porous block article, such as the addition of an antimicrobial agent. An agent, such as AgBr has been added to a porous block article, as described in US 7,144,533 and US 8,622,224. Each of these references describes a complicated method for adding a metal (preferably Ag or Cu) salt into a filtration device, involving first charging the activated carbon or binder, then adding a charged microbiological interception agent. AgBr can be added at about 0.05 to 0.5 %, with a particle size of about a micrometer.

There is a relationship between the level of loading of these functional additives, the size of the functional additive, and the available surface area of the functional additive in a porous block article. It is desired to have a large amount of surface area of a functional additive available, to maximize effectiveness as a filtration/active agent.

Small functional additive particles provide the most surface area - and thus the highest distribution efficiency per weight of additive by volume of filtration article.

However, when the functional additive is a smaller particle size relative to "standard" binder particle size available today, the binding efficiency is decreased resulting in some "loose" functional additive particles. This can be seen because some of these smaller particle size additives wash out of the porous block article and are seen as turbid effluent - especially with an "unused" porous filtration/adsorption article. In the art this problem is handled by either using large functional particles (generally 10 micrometers or larger) - similar in size to the adsorbent particles, or else nano-sized functional additive particles may be used, but only a low levels (far less than 1% and preferably less than 0.5%). Alternatively, a higher level of binder could be employed, but the more binder, the less surface area of the functional additive particles is available for filtration, due to the displacement of adsorbents. A few of the functional additives are available in nano-size - having large surface areas available for reactions.

In PCT/US 16/28032, the problem of increasing the concentration of functional additive was solved by pairing sub -micrometer functional additives with sub-micrometer discrete binder particles where a higher loading of functional additive nano-particles were achieved, while the binder remains effective to bind the adsorbent particles. In the Examples, a functional additive level of up to 11 wt% on the solid porous article was obtained. The level of binder in the Examples is always much greater than the level of functional additive.

Surprisingly it has now been found that even higher levels of discrete functional additives can be incorporated into a fine particulate synthesized binder, providing increased functionality, while retaining good binding properties. The functional additive level can be, and in a preferred embodiment is, greater than the level of binder. The fine particle synthesized binder can be used by itself, or combined with additional adsorbents to form porous block articles with higher functional additive content than described in prior art. The fine particulate synthesized binder is useful for removing contaminants, and especially heavy metals, as shown in the examples herein.

SUMMARY OF THE INVENTION

Within this specification embodiments have been described in a way which enables a clear and concise specification to be written, but it is intended and will be appreciated that embodiments may be variously combined or separated without parting from the invention. For example, it will be appreciated that all preferred features described herein are applicable to all aspects of the invention described herein. Aspects of the invention include:

1. A fine particle synthesized binder comprising: a) from 15 to 70 weight percent, and preferably from 25 to 49 weight percent of one or more thermoplastic polymeric binders, based on the total amount of thermoplastic binder and functional additives, in the form of particles having an average particle discrete size of from 20 nm to 4 micrometers, preferably 40nm to 1 micrometer, and most preferably 50nm to-400 nm, and having a and having a melt viscosity of between 300, and 150,000 Pascal seconds, preferably greater than 10,000 Pascal seconds, as measured at a shear rate of 1 reciprocal second on a parallel plate rheometer at 232 °C (450°F), and b) from 30 to 85 weight percent, and preferably from 51 to 75 weight percent, of one or more functional additive particles, based on the total amount of thermoplastic binder and functional additives having an average particle size of from 5 nm to 50,000 nm, preferably from lOnm to 15,000nm, and most preferably from 20nm to 8,000 nm. 2. The fine particle synthesized binder of aspect 1, wherein said thermoplastic polymer binder is selected from the group consisting fluoropolymers, styrene-butadiene rubbers (SBR), ethylene vinyl acetate (EVA), (meth)acrylic polymers, polyurethanes, styrenic polymers, polyamides, polyolefins, polyethylene, polypropylene, polyesters,

polycarbonates, polyether ether ketone (PEEK), polyether ketone (PEKK),and

thermoplastic polyurethane (TPU).

3. The fine particle synthesized binder of aspects 1 or 2, wherein said thermoplastic polymer binder is a fluoropolymer selected from the group consisting of one or more of the following monomers of vinylidene fluoride (VDF or VF2), tetrafluoroethylene (TFE), trifluoroethylene (TrFE), chlorotrifluoroethylene (CTFE), hexafluoropropene (HFP), vinyl fluoride (VF), hexafluoroisobutylene (HFIB), perfluorobutylethylene (PFBE), pentafluoropropene, 3 ,3 ,3 -trifluoro - 1 -propene, 2-trifluoromethyi- 3 , 3 ,3 -trifluoropropene, fluorinated vinyl ethers including peril uoromethyl ether (PMVE), perfluoroethylvinyl ether (PEVE), ethylene tetrafluoroethylene (ETFE), ethylene fluoro

trichloroethylene(ECTFE), perfluoropropvlvinyl ether (PPVE), perfluorobutylvinyl ether (PBVE), 2,3,3, 3-tetrafluoropropene, longer chain perfluorinated vinyl ethers, fhiorinated dioxoles, partially- or per-fluorinated alpha olefins of C and higher, partially- or perfluorinated cyclic alkenes of C3 and higher, there copolymers and combinations thereof,

4. The fine particle synthesized binder of any or aspects 1 to 3, wherein said

fluoropolymer is a homopolymer of vinylidene fluoride, or a copolymer comprising greater than 70 weight percent of vinylidene fluoride monomer units.

5. The fine particle synthesized binder of any or aspects 1 to 4, wherein the ratio of said functional additive average particle size to said binder average particle size is from 0.05 to 100, preferably from 0.3 to 10, and most preferably from 0.5 to 5.

6. The fine particle synthesized binder of aspect 5, wherein said functional additive has an average particle size greater than the average particle size of said polymer binder.

7. The fine particle synthesized binder of any or aspects 1 to 6, wherein said functional additive is selected from the group consisting of metals; such as silver, zinc, iron, titanium, copper, and alloys of silver, zinc, iron, titanium, and copper; phosphate minerals, triphylite, monazite, hinsdalite, pyromorphite, vanadinite, erythrite,

amblygonite, lazulite, turquoise, autunite, phosphophyllite, struvite, xenotime;

phosphates of apatite and mitridatite groups, oxide minerals, periclase, zincite, hematite, rutile, spinel groups; cuprite, baddeleyite, uraninite, thoriranite, chrysoberyl, and columbite, hydroxide minerals, goethite group, brucite, manganite, romanechite, silicates, phenakite, olivine, garnet, zircon, aluminum silicate, aluminosilicate, alumino solicicate, humite, epidote, pyroxene, pyroxenoid, amphibole, serpentine, clay mineral, mica, chlorite, quartz, feldspar, feldspathoid, scapilite, zeolite groups; datolite, titanite, chloritoid, mullite, hemimorphite, lawsonite, llvaite, vesuvianite, beitoite, axinite, beryl, sugilite, corierite, tourmaline, petalite, analcime, carbonate minerals, such as calcite, aragonite, dolomite, monoclinic groups; hydromagnesite, ikaite, lansfordite,

monohydrocalcite, natron, zellerite, alginic acids and alginic salts, metal organic frame (MOF) works, such as bidentate or tridentate carboxylates, azoles, and other ligand types, and single or multiple crystal molecular sieves. 8. The fine particle synthesized binder of any or aspects 1 to 7, further comprising 60 to 90 wt%, preferably 70 to 85 wt% of adsorbent fine particle particles, based on the total weight of binder, functional additive and adsorbent.

9. The fine particle synthesized binder of aspect 10, wherein said adsorbent fine particle particles are selected from the group consisting of activated carbon, carbon molecular sieves, molecular sieves, silica gel, metal organic framework, and carbon fibers.

10. A fine particle synthesized binder comprising a) one or more thermoplastic polymeric binders, based on the total amount of thermoplastic binder and functional additives, in the form of particles having an average particle discrete size of from 20 nm to 50

micrometer, preferably 50 nm to 20 micrometers, and having a melt viscosity of between 300, and 150,000 Pascal seconds, preferably greater than 10,000 Pascal seconds, as measured at a shear rate of 1 reciprocal second on a parallel plate rheometer at 232 °C (450°F); and b) one or more functional additive particles, having an average particle size of from 5 to 10 micrometers, wherein said functional additive particles are aluminosilicates.

11. A three dimensional solid porous article comprising the composition of any or aspects 1 to 10.

12. The three dimensional solid porous article of aspect 11, further comprising 60 to 90 wt%, preferably 70 to 85 wt% of adsorbent fine particle particles, based on the total weight of binder, functional additive and adsorbent.

13. The three dimensional solid porous article of aspects 11 or 12, wherein said article is used to remove heavy metals from fluid streams.

DESCRIPTION OF THE DRAWINGS

Figure 1 is a plot of the rejection curve for lead, using the composition of the invention, as described in Example 4 Figure 2 is a plot of the rejection curve for mercury, using the composition of the invention, as described in Example 4

DETAILED DESCRIPTION OF THE INVENTION:

The invention relates to a fine particle synthesized binder of small particle size functional additives, polymer binder particles, and optionally adsorbent particles. The fine particle synthesized binder can be processed into a porous solid block article for the removal of contaminants from a fluid (liquid or gas) stream.

As used herein "copolymer" refers to any polymer having two or more different monomer units, and would include terpolymers and those having more than three different monomer units.

"Fine particulate" or "fine particles" or "powder", as used herein, refers to particles in the form of granules, beads, fibers, and agglomerates of discrete particles.

"Synthesized", as used herein, refers to combination of two or more fine particlesinto a single binder composition.

The references cited in this application are incorporated herein by reference. Percentages, as used herein are weight percentages, unless noted otherwise, and molecular weights are weight average molecular weights as measured by GPC using a PMMA reference, unless otherwise stated.

Particle size is a number average particle size, as measured by laser diffraction for particles having a mean diameter of less than 500 micrometers, whilesieve analysis is used for larger particles. Discrete particle size is the average particle size of discrete (individual) particles in fine particulates, fine particles, or powders, and is determined by imaging with a SU8010 scanning electron microscope (SEM), after samples are coated with a thin layer of iridium using an ion beam coater.

Polymer Binder:

The thermoplastic binder particles of the fine particle synthesized binder of the invention are thermoplastic polymer particles, preferably in the low- and sub-micrometer range. The particle size, and the discrete particle size, is less than 50 micrometer, preferably less than 10 micrometers, more preferably less than 5 micrometer and preferably less than 1 micrometer, preferably less than 500 nm, preferably less than 400 nm, and more preferably less than 300 nm. The particle size, and the discrete particle size, is generally at least 20 nm and preferably at least 50 nm.

Useful polymers include, but are not limited to fluoropolymers, styrene -butadiene rubbers (SBR), ethylene vinyl acetate (EVA), acrylic polymers such as polymethyl methacrylate polymer and copolymers, polyurethanes, styrenic polymers, polyamides, polyolefins, including polyethylene, and polypropylene and the copolymers thereof, polyester including polyethylene terephthalate, polyvinyl chlorides, polycarbonate, polyether ether ketone (PEEK), polyether ketone ketone (PEKK), and thermoplastic polyurethane (TPU). In order to obtain the small polymer particle size useful in the invention, it is preferred that the thermoplastic polymers are made by emulsion (or inverse emulsion) polymerization. Alternatively other polymerization methods could be used, followed by grinding, milling, crushing, or other known means of reducing the particle size.

Preferred polymers are polyamides, and fluoropolymers, with homopolymers and copolymers of polyvinylidene fluoride being especially useful. Polyvinylidene fluoride (PVDF) polymer and copolymers will be used in this application as exemplary polymer binders. One of ordinary skill in the art will understand and be able to apply the specific references to PVDF to these other thermoplastic polymers, which are considered to be within the realm of, and embodied in the invention.

In one preferred embodiment, the binder is a fluoropolymer. Useful

fluoropolymers are thermoplastic homopolymers and copolymers having greater than 50 weight percent of fluoromonomer units by weight, preferably more than 65 weight percent, more preferably greater than 75 weight percent and most preferably greater than 90 weight percent of one or more fluoromonomers. Useful fluoromonomers for forming the fluoropolymer include but are not limited to: vinylidene fluoride (VDF or VF2), tetrafluoroethylene (TFE), trifluoroethylene (TrFE), chlorotrifluoroethylene (CTFE), hexafluoropropene (HFP), vinyl fluoride (VF), hexafluoroisobutylene (HFIB), perfluorobutylethylene (PFBE), pentafluoropropene, 3,3,3-trifluoro-l-propene, 2- trifluoromethyl-3,3,3-trifluoropropene, fluorinated vinyl ethers including perfluoromethyl ether (PMVE), perfluoroethylvinyl ether (PEVE), perfluoropropylvinyl ether (PPVE), perfluorobutylvinyl ether (PBVE), longer chain perfluorinated vinyl ethers, fluorinated dioxoles, partially- or per-fluorinated alpha olefins of C ₄ and higher, partially- or per- fluorinated cyclic alkenes of C ₃ and higher, and combinations thereof.

Especially preferred fluoropolymers are polyvinylidene fluoride (PVDF) homopolymers, and copolymers, such as Kyblock ^® resins from Arkema, and tetrafluoroethylene (PTFE) homopolymers and copolymers (such as FEP, PFA, ETFE, etc) and terpolymers of

tetrafluoroethylene/hexafluoropropylene/vinylidene difluoride (THV).

In one embodiment, vinylidene fluoride copolymers are preferred, due to their lower crystallinity (or no crystallinity), making them more flexible than the semi- crystalline PVDF homopolymers. Flexibility of the binder allows it to better withstand the manufacturing process. Preferred copolymers include those containing at least 50 mole percent, preferably at least 75 mole %, more preferably at least 80 mole %, and even more preferably at least 85 mole % of vinylidene fluoride copolymerized with one or more comonomers selected from the group consisting of tetrafluoroethylene, trifluoroethylene, chlorotrifluoroethylene, hexafluoropropene, vinyl fluoride,

pentafluoropropene, 2,3,3,3-tetrafluoropropene, trifluoropropene, perfluoromethyl vinyl ether, perfluoropropyl vinyl ether and any other monomer that would readily

copolymerize with vinylidene fluoride.

In one embodiment, up to 30%, preferably up to 25%, and more preferably up to 15 % by weight of hexafluoropropylene (HFP) units and 70% or greater, preferably 75% or greater, more preferably 85% or greater by weight or more of VDF units are present in the vinylidene fluoride polymer.

The PVDF used in the invention is generally prepared by means known in the art, using aqueous free-radical emulsion polymerization - although suspension, solution and supercritical C0 ₂ polymerization processes may also be used. In a general emulsion polymerization process, a reactor is charged with deionized water, water-soluble surfactant capable of emulsifying the reactant mass during polymerization and optional paraffin wax antifoulant. In one preferred embodiment, the surfactant is a non- fluoro surfactant, and the product is fluorosurfactant-free. The mixture is stirred and deoxygenated. A predetermined amount of chain transfer agent, CTA, is then introduced into the reactor, the reactor temperature raised to the desired level and vinylidene fluoride (and possibly one or more comonomers) are fed into the reactor. Once the initial charge of vinylidene fluoride is introduced and the pressure in the reactor has reached the desired level, an initiator emulsion or solution is introduced to start the polymerization reaction. The temperature of the reaction can vary depending on the characteristics of the initiator used and one of skill in the art will know how to do so. Typically the temperature will be from about 30° to 150°C, preferably from about 60° to 120°C. Once the desired amount of polymer has been reached in the reactor, the monomer feed will be stopped, but initiator feed is optionally continued to consume residual monomer. Residual gases (containing unreacted monomers) are vented and the latex recovered from the reactor.

The thermoplastic latex binder is generally reduced to a powder form by spray drying, coagulation, or other known process, to produce a dry powder. The

powderization can occur on the latex alone, or on the polymer latex combined with one or more the functional additives.

The PVDF polymerization results in a latex generally having a solids level of 10 to 60 percent by weight, preferably 10 to 50 percent.

Binder particles from emulsion polymers useful in the invention generally have discrete particle sizes from 20 to 4000 nm, preferably from 40 to 1000 nm, and more preferably from 50 to 400 nm. In some cases, polymer particles may agglomerate into particle sizes of 1 to 150 micrometer groupings, 3 -50 micrometers, 5-15 micrometers, and preferably 6-8 micrometer agglomerates. It has been found that these agglomerates generally break into individual discrete particles during processing to form an article. The discrete particles themselves are essentially spherical, while agglomerates are irregular, and not spherical. During processing into articles, the discrete particles which start essentially spherical are deformed by pressure into thin oblong particles that bind adjoining adsorbent material together and provide interconnectivity.

The binder level (weight percent) is optimized to use as little as necessary to adequately hold the functional additive and adsorbent materials together. Lower levels of binder allow more of the surface area of the functional additives and adsorbent to be exposed and active. One advantage of PVDF binders is that they have a very high density of about 1.78 g/cc. Thus, at an equivalent weight percent to standard binders like LDPE, the PVDF level represents an even lower volume percent of a filtration article - allowing for more available functional additive and adsorption additive surface area. The high molecular weight PVDF resin results in the binder not flowing into the carbon and fouling the high surface area of the activated carbon sorption media. The melt viscosity of the PVDF is greater than 300, and less than 150,000 Pascal seconds, preferably greater than 10,000 Pascal seconds, as measured at a shear rate of 1 reciprocal second on a parallel plate rheometer at 232 °C (450°F). Specifically: Anton-Paar MCR 500 rheometer with 25 mm parallel plates. Strain amplitudes were -1%, within the linear viscoelastic region.

Functional Additives:

"Functional additives" as described herein are materials which are added to adjust the overall performance of the final manufactured porous solid block, including but not limited to, heavy metal adsorbents and/or coagulants, pH modifiers, microbiological interceptors, inorganic and/or organic chemical reducers, disinfectant and/or disinfectant by-product reducers, flow aids, hydrophilic/hydrophobic modifiers, gas adsorbent, catalyst for chemical reactions.

One or more functional additives are added to the composition to provide the composition, and any articles made from it, with functionality for biological interception, metal adsorption, metal precipitation, physical filtration, catalytic activity, ion exchange, enzyme conversion, enzymes, antibodies, bacteria & virus rejection, and proteins immobilized on a support substrate. Many of these additives have particle sizes in the range of 5 to 50,000 nm, preferably from 10 to 10,000 nm, more preferably from 20 nm to 8,000 nm, and more preferably from 25 to 2,000 nm, enabling a large surface area for interaction with the fluid. While it is possible to use very low loadings of less than 1 weight percent of these small functional additives (based on the total weight of the porous article) with binder particles averaging over 5 micrometers, by using nano-particle sized binder, it is possible to have loading levels of these small particle size functional additives of greater than 1 weight percent, greater than 5 weight percent, and even greater than 10 weight percent. The ratio of the functional additive average particle size to the binder average particle size is from 0.3 to 10, and preferably 0.5 to 5. In a preferred embodiment, the binder average particle size is less than the functional additive average particle size. The functional additive is generally in particulate, powder or granular form.

Preferably the functional additive is inorganic, though functional organic additives may also be used. Smaller discrete particles may aggregate to an irregular agglomerate of up to 50 micrometer.

Examples of useful functional additive include, but are not limited to:

Phosphate minerals, such as triphylite, monazite, hinsdalite, pyromorphite, vanadinite, erythrite, amblygonite, lazulite, turquoise, autunite, phosphophyllite, struvite, xenotime; and apatite and mitridatite groups.

Oxide Minerals, such as periclase, zincite, hematite, rutile, spinel groups; cuprite, baddeleyite, uraninite, thoriranite, chrysoberyl, and columbite.

Hydroxide Minerals, such as goethite group, brucite, manganite, and romanechite.

Silicates, such as phenakite, olivine, garnet, zircon, aluminum silicate,

aluminosilicate, humite, epidote, pyroxene, pyroxenoid, amphibole, serpentine, clay mineral, mica, chlorite, quartz, feldspar, feldspathoid, scapilite, zeolite groups; datolite, titanite, chloritoid, mullite, hemimorphite, lawsonite, llvaite, vesuvianite, beitoite, axinite, beryl, sugilite, corierite, tourmaline, petalite, and analcime.

Carbonate Minerals, such as calcite, aragonite, dolomite, monoclinic groups;

hydromagnesite, ikaite, lansfordite, monohydrocalcite, natron, zellerite, calcium carbonate, sodium bicarbonate.

Alginic acids and alginic salts.

Metal organic frame (MOF) works, such as bidentate or tridentate carboxylates, azoles, and other ligand types.

Metals, including but not limited to silver, zinc, iron, titanium, copper, and their alloys.

Polymeric materials, including but not limited to chitosan, lignin, polypyrrole, cellulose and cellulosics.

A preferred type of functional additives is aluminosilicates.

Examples of useful microbiological inception agents include, but are not limited to metal salts, particularly silver and copper salts, including AgBr, Ag CI, copper- zinc alloys, and silver zeolite. Other useful functional additives include iron hydroxide - for the adsorption of arsenic, calcium hydroxyapatite - for the adsorption of fluorine, and phosphates, oxides and sulfates - for the precipitation of metals such as lead, nickel and other toxic metals or to promote oxidation-reduction (REDOX) reactions that support formation of benign chemistries

Some aluminosilicates, and especially those of 5 nm to 50 micrometers particle size, preferably 10 nm to 8 micrometers particle size, are especially useful as functional additives. The larger size particles have reduced fouling when used with larger polymer binder (having an average particle size of 1 to 50 micrometers), leading to better adhesion (more unfouled binder available for bonding). The ratio of the functional additive weight average particle size to the polymer binder weight average particle size is in the 0.05 to 100 range.

Preferably in this invention, the weight percent of polymer binder to functional additive is from 15 to 70 weight percent binder to 30 to 85 weight percent functional additive, more preferably from 25 to 49 weight polymer binder to 51 to 75 weight percent functional additive.

Adsorbent

The fine particle synthesized binder can be used by itself to form articles that can remove heavy metals and other contaminates from a fluid stream - liquid or gaseous. Optionally, other components can be part of the fine particle synthesized binder composition of the invention. These include adsorbents, fillers, and pH modifiers.

The adsorbents of the invention are those capable of adsorbing and desorbing specific molecules. Useful adsorbents include, but are not limited to: activated carbon, molecular sieves, silica gel, metal organic framework, etc., which have special affinity to adsorb specific materials. Activated carbon, carbon fibers and molecular sieves are especially useful adsorbents of the invention. Activated carbon having a large level of surface area is especially preferred, as are nano carbon fibers, in order to maximize the surface area of the sorbent.

The adsorbent particles of the invention are generally in the size range of 0.1 to 3,000 micrometers, and preferably from 1 to 500 micrometers in diameter, with fibers being 0.1 to 250 micrometers in diameter of essentially unlimited length to width ratio. Fibers are preferably chopped to no more than 5 mm in length. Adsorbent fibers or powders should have sufficient thermal conductivity to allow heating of the fine particulate mixtures. In addition, in an extrusion or compression molding process, the particles and fibers must have melting points sufficiently above the melting point of the fluoropolymer binder resin to prevent both substances from melting and producing a continuous melted phase rather than the usually desired multi phase system.

There are many sources of activated carbon and various techniques to

differentiate the performance of each activated carbon per application. Sources of activated carbon include, but are not limited to, agricultural waste, biological waste, industrial waste, coconut shell, bitumen, coal, grass, organic polymers, bamboo, hard wood, and soft wood. Each product has their own characteristics which can affect gas or liquid sorption and desorption performance. It is known that for gas sorption onto activated carbon it is dependent on the close proximity to surface area contact coupled with Van der Waal's forces to attract gas molecules and temporarily store them until desorption occurs. Key characteristics of the activated carbon which impacts the volume of gas sorption is the macro-, micro-, meso- porosity of the carbon surface area. The porosity is further characterized by the N ₂ adsorbtion and Brunauer-Emmett specific BET surface area is preferred. A key property related to manufacturing with solid state extrusion or compression molding methods is the apparent density, as measured by ASTM D2854, for material conveying and the hardness, as measured by ASTM D3802, when densifying.

When the fine particle synthesized binder is used in combination with an adsorbent, the adsorbent typically makes up 60 to 90, and preferably 70 to 85 weight percent of the total composition.

Processing

To produce the fine particle synthesized binder - The binder and functional additive(s) may be combined by means known in the art, including, but not limited to: a) A powder/powder blend. The functional additive(s) and binder as powders may be combined by physical blending, such as by high shear and low shear agitation. The powder-powder blend can be formed with or without the use of a dispersant, such as silica.

b) A powder/liquid blend. The binder could be in the form of an emulsion latex, and could be added onto the functional additive powder by known means such as spray, dipping, and coating, followed by drying of fine particle synthesized binder.

c) A liquid/liquid blend. The binder in the form of an emulsion latex can be blended and stirred with an aqueous suspension of the functional additive(s). The mixture could be dried by a typical means, such as freeze drying, and spray drying.

Further, aqueous streams of the binder and functional additive could be co-spray dried or precipitated, forming a fine particle synthesized binder from the two powders.

Fine particle synthesized binders obtained by any of the above methods, could be further sintered together to form larger agglomerates. This reduces dusting issues with the fine powders. The sintered powders will separate under a shear force during processing into a block structure. The sintering process is also called densification.

The fine particle synthesized binder can be combined with the optional, larger adsorbent particles by typical means such as ribbon blending, planetary mixer, tumble mixer and other common powder blending methods.

In one embodiment, the functional additive, adsorbent particles and binder particles can be dry blended, In another embodiment, the functional additive and adsorbent particles can be added to a polymer emulsion, followed by drying of the fine particle synthesized binder. The polymer latex can be diluted to 4-25 weight percent of solids, and preferably from 10 to 20 weight percent solids by the addition of water with stirring. The dilution allows for a better dispersion with the active particles, and decreases the likelihood of polymer particle agglomeration. One or more types of adsorbents and functional additive particles are then added to the diluted latex with adequate stirring to form a homogeneous aqueous dispersion of the polymer particle and interactive materials. This process works well for particles that are not water sensitive or hydrophobic, but does not work well for particles, such a molecular sieves, that are known to adsorb water or are hygroscopic, and which could become clogged with addition of a latex. The wet dispersion blend is dried to form a composite of the adsorbent materials with the sub-micrometer polymer binder particles with the functional additive particles on the surface. The drying step can be done by any known method that will form the fine particle synthesized binder with the formation of less than 10 weight percent, and preferably less than 5 weight percent of polymer agglomerates. Drying generally uses heat and/or vacuum to remove the water and produce the fine particle synthesized binder. In one embodiment, the dispersion blend is spray-dried to form the fine particle synthesized binder. Dried polymer particle agglomerates in the 5-300 micrometer average particle size range can result from agglomeration of the 20- 500 nm discrete polymer binder particles. Preferably the agglomerates are kept to a minimum. In another embodiment, the blend dispersion is poured onto a belt conveyor and a combination of vacuum and heat (generally an oven) is used to drive off the water, and to sinter the polymer particles to the interactive material. The flat sheet structure formed can then be collected and rolled into semi-finished good which could be die cut to dimensions or pleated and further wrapped into filtration cartridges.

The dry fine particle synthesized binder composition of the invention can be formed into useful objects by any number of methods known in the art. The process should be one that may soften the polymer particles, but will not cause them to melt and flow to the point that they contact other polymer particles and form agglomerates or a continuous layer. To be effective in the contemplated end-uses, the polymer binder remains as discreet polymer particles that bind the functional additive particles and optional adsorbent particles into an interconnected web, so gases and liquids can easily flow and contact the interactive materials.

In one embodiment, the dry fine particle synthesized binder can be re-dispersed in an aqueous or solvent dispersion, by means of a dispersing aid, as known in the art. The polymer binder will remain uniformly distributed and in a non- agglomerated particle form as part of the fine particle synthesized binder. The dispersion can then be applied to substrate surfaces that will contact fluids.

In another embodiment, the polymer binder particles, adsorbent particles and functional additive particles can be formed into a porous block article in an extrusion process, such as that described in US 5,331,037. The fine particle synthesized binder of the invention is dry-blended with other additives, such as processing aids, and extruded, molded or formed into articles. Continuous extrusion under heat, pressure and shear while can produce an infinite length 3 -dimensional multi phase profile structure consisting of binder, interactive particles, air, and/or other additives. In order to form the continuous web of forced-point bonding of binder to the adsorbent and functional additive particles, a critical combination of applied pressure, temperature and shear is used. The fine particle synthesized binder and additive blend is brought to a temperature above the softening temperature of the binder, significant pressure applied to consolidate the materials, and enough shear to spread the binder and form a continuous web. The porous block article is useful for separation and filtration of liquid and gaseous streams.

In yet another embodiment, the fine particle synthesized binder composition is formed into a dry sheet on a conveyor belt, and the sheet formed into articles.

In another embodiment, the fine particle synthesized binder can be added to a compression molder under sufficient heat and pressure to bind the fine particle synthesized binder into a multi-phase system of binder, interactive particle, air, and/or other additives.

In one embodiment, a non-compression molding process is used to form the fine particle synthesized binder into a final article, where the non-compression process uses only gravity, and no added compression force.

Uses

The fine particle synthesized binder composition of the invention can be used to form separation articles, including block articles, which are useful from removing anionic, cationic, and oxy ion contaminates, from a fluid stream. Removal of heavy metals is a preferred use of separation articles made from the composition of the invention.

The separation articles of the invention differs from membranes. A membrane works by rejection filtration - having a specified pore size, and preventing the passage of particles larger than the pore size through the membrane. The separation articles of the invention instead rely on adsorption or absorption of by interactive particles to remove materials from a fluid passing through the separation device, however due to the solid structure it can also act as a particulate filter by rejecting particles or trapping particles within the formed structure.

The separation articles of the invention, having interconnectivity of interactive particles, can be formed by means known in the art for forming solid articles. Useful processes for forming the separation articles of the invention include, but are not limited to: an extrusion process, as taught in US 5,019,311, compression molding, and an

(aqueous) dispersion binding process.

The separation articles can be used to purify and remove unwanted materials from the fluid passing through the separation article, resulting in a more pure fluid to be used in various commercial or consumer applications. The separation article can also be used to capture and concentrate materials from a fluid stream, these captured materials then removed from the separation article for further use. The separations devices can be used for potable water purification (hot and cold water), and also for industrial uses. By industrial uses is meant uses at high temperatures (greater than 50°C, greater than 75°C, greater than 100°C greater than 125°C and even greater than 150°C, up to the softening point of the polymer binder; uses with organic solvents, and in pharmaceutical and biological clean and pure uses.

Separation articles of the invention can be any size or any shape. In one embodiment, the article is a hollow tube formed by a continuous extrusion of any length. Water or other fluid flows under pressure through the outside of the tube, and is filtered from the outside to inside of the tube, and is collected after passing through the filter. In another embodiment, the article is a solid cylinder formed by continuous extrusion or compression molding. Water or other fluid flows under pressure radially from one end to the other.

Articles formed from the composition of the invention are useful for the removal of inorganic and ionic species from aqueous, non-aqueous, and gaseous suspensions or solutions, including but not limited to cations of hydrogen, aluminum, calcium, lithium, sodium, and potassium; anions of nitrate, cyanide and chlorine; metals, including but not limited to chromium, zinc, lead, mercury, copper, silver, gold, platinum, iron, calcium, magnesium, and other precious or heavy metal and metal ions; salts, including but not limited to sodium chloride, potassium chloride, sodium sulfate; and removal of organic compounds from aqueous solutions and suspensions.

In one embodiment, an article formed from the composition of the invention is used to remove mercury vapor from a gaseous stream. In another embodiment, an article formed from the composition of the invention is used to remove mercury and other heavy metals from an aqueous stream, including potable water and industrial waste water.

The fine particle synthesized binder composition of the invention can also be used to form articles for gas storage, or catalysis of chemical reactions.

Based on the list of exemplary uses, and the descriptions in this description, one of ordinary skill in the art can imagine a large variety of other uses for the fine particle synthesized binder-based solid article of the invention.

EXAMPLES:

Example 1:

A fine particle synthesized binder composition of 40 weight percent

poly(vinylidene difluoride) (PVDF) binder and 60 weight percent apatite salt was combined in a high shear mixer to form a powder blend. The PVDF powder had 6 micrometers agglomerate particle size, as determined by laser diffraction and a melt viscosity of 15100 Pascal seconds at 1 reciprocal second as measured at 350 degrees Fahrenheit (177 degrees Celsius) on a parallel plate rheometer. The apatite salt had a particle size of 3 micrometers also determined by laser diffraction. The fine particle synthesized binder was then combined with activated carbon (Oxbow Activated Carbon OXPURE 5250- AW/70) screened between 50 mesh (297 micrometers) and 250 mesh (58 micrometers) in a planetary mixer for approximately 20 minutes. The composition of the final mixture was 30 weight percent "binder blend" and 70 weight percent activated carbon. The average discrete particle size of the PVDF binder in the final mixture was 400nm, as determined by scanning electron microscopy (SEM).

The mixture was added to an annular mold with an outside diameter of 2.5 inches (6.35 centimeters) and an inside diameter of 1.25 inches (3.18 centimeters) and heated to 400 degrees Fahrenheit (204 degrees Celsius) for 1 hour. The mold was removed from the oven and 200 pounds of force (890 Newton) applied to the mold. The block was allowed to cool to room temperature, ejected from the mold, and cleaned with

compressed air. The block was then trimmed to approximately 5 inches (12.7

centimeters) long and end caps were glued on with hot melt adhesive. The block was then loaded into an in line, outside in fixture.

Deionized water was run through the filter housing at about 60 pounds per square inch and the first gallon (3.78 liters) of filtrate was collected. The turbidity of the filtrate was tested with Fisher Scientific bench top turbidity meter as a measure of how well the heavy metal particles were retained. If the water was turbid with a value greater than 5 Nephelometric Turbidity Units (NTU) the small particle size metal adsorbent was not properly retained. The turbidity of the first gallon of filtered water from the block produced in Example 1 was 1-2 NTU, indicating good retention of the small particle size binder.

Additionally, the surface area of the block was tested by nitrogen adsorption and the Brunauer-Emmett-Teller (BET) method using a Quantachrome instruments Nova 2200e surface are analyzer to estimate the degree of fouling or pore blinding caused by the binder. The carbon block filter had a surface are of 750-800 square meters per gram.

Example 2:

A fine particle synthesized binder composition of 40 weight percent

poly(vinylidene difluoride) (PVDF) binder and 60 weight percent molecular sieve was combined in the same method described in Example 1 to produce a fine particulate blend. The molecular sieve had an average particle size of 3 micrometers. The fine particle synthesized binder was used as a binder for an activated carbon filter and tested using the same composition and methods described in Example 1. The average discrete particle size of the PVDF binder in the final mixture was 400nm, as determined by scanning electron microscopy (SEM). The turbidity of the first gallon of filtrate was 1-2 NTU indicating moderate retention of the adsorbent particles.

Example 3:

A fine particle synthesized binder composition of 40 weight percent

poly(vinylidene difluoride) (PVDF) binder and 60 weight percent molecular sieve was combined in the same method described in Example 1 to produce a fine particulate blend. The molecular sieve had an average particle size of 7 micrometers. The fine particle synthesized binder was used as a binder for an activated carbon filter and tested using the same composition and methods described in Example 1. The turbidity of the first gallon of filtrate was less than 1 NTU indicating good retention of the adsorbent particles.

Example 4:

A blend of 25wt% fine particle synthesized binder (Kyblock® FX415 resin, a poly(vinylidene difluoride (PVDF) binder from Arkema Inc.) blended with 75wt% 80x325mesh coconut activated carbon mixed into a powder. The powder was extruded into a porous carbon block filtration device for removal of heavy metals from water. a) The filtration device was tested under conditions specified under ANSI

NSF53 test conditions for the removal of lead at pH 6.5, below (Figure 1) is the rejection curve indicating that the synthesized blend provided functionality to remove lead from a water stream.

b) The filtration device was tested under conditions specified under ANSI

NSF53 test conditions for the removal of mercury at pH6.5, below (Figure 2) is the rejection curve indicating that the synthesized blend provided functionality to remove mercury from a water stream.

Comparative example 1 :

A fine particle synthesized binder composition of 40 weight percent

poly(vinylidene difluoride) (PVDF) binder and 60 weight percent apatite was prepared by the method described in Example 1. The PVDF binder has a nominal particle size of 200 micrometers granules as determined by optical microscopy, with no significant population of discrete particles (<5 microns). The PVDF binder had a melt viscosity of 17,200 Pascal seconds at 1 reciprocal second as determined by the same method in Example 1. The fine particle synthesized binder was used as a binder for an activated carbon filter and tested using the same composition described in Example 1. The average particle size of the PVDF binder remained unchanged in the final blend. Upon ejection, the block did not have sufficient structural integrity to test. Comparative example 2:

A fine particle synthesized binder composition of 40 weight percent ultra-high molecular weight polyethylene (UHMWPE) and 60 weight percent apatite was prepared by the method described in Example 1. UHMWPE has a nominal particle size of 250 micrometers as determined by optical microscopy, with no significant population of discrete particles (<5 microns). Fine particle synthesized binder had a melt viscosity of 123,000 Pascal seconds at 1 reciprocal second as measured at 350 degrees Fahrenheit as determined by the same method in Example 1. fine particle synthesized binder was used as a binder for an activated carbon filter and tested using the same composition described in Example 1. Upon ejection, the block did not have sufficient structural integrity to test.

Comparative example 3:

A fine particle synthesized binder composition of 40 weight percent low density polyethylene (LDPE) and 60 weight percent apatite was prepared by the method described in Example 1. The LDPE has a nominal particle size of 20 micrometers as determined by the same method described in Example 1. The polymer binder had a melt viscosity of 1330 Pascal seconds at 1 reciprocal second as measured at 350 degrees Fahrenheit as determined by the same method in Example 1. The fine particulate blend was used as a binder for an activated carbon filter and tested using the same composition described in Example 1, with no significant population of discrete particles (<5 microns). The turbidity of the first gallon of filtrate was 5-6 NTU indicating poor retention of the adsorbent particles. Surface area of the block, as determined by the same method described in example 1 was 530 square meters per gram, indicating high fouling.

Comparative example 4:

A fine particle synthesized binder composition of 70 weight percent binder as in Example 2, and 30 weight percent apatite was prepared by the method described in Example 1. The fine particle synthesized binder was used as a binder for an activated carbon filter and tested using the same method described in Example 1 except the composition was 40 percent binder and adsorbent pre-blend and 60 percent carbon. The turbidity of the first gallon of filtrate was 5-7 NTU indicating poor retention of the adsorbent particles