POLYMERS, FLUORINATED IONIC POLYMER NETWORKS, AND METHODS RELATED THERETO

Disclosed herein are materials and methods related to the removal of a polyfluorinated alkyl compound from water. The materials contain both fluorine and an ion, which materials can be used as a network to remove the polyfluorinated alkyl compound from water.

BACKGROUND

Thus, there is a need to remove polyfluorinated alkyl compounds from water to make it safer for the public. Disclosed herein are materials, polymers and methods useful in the removal of polyfluorinated alkyl compound from water.

SUMMARY

In accordance with the purpose(s) of the invention, as embodied and broadly described herein, the invention, in one aspect, relates to fluorinated ionic polymer networks and methods related thereto.

Disclosed herein is a method of removing a polyfluorinated alkyl compound from water, the method comprising absorbing the polyfluorinated alkyl compound from the water with a fluorinated ionic polymer network.

Also disclosed here is a co-polymer made from: a monomer comprising an ion generating moiety having the structure

wherein each R2group independently is H, C1-C6 alkyl, C1-C6 fluoroalkyl, aryl, or fluoroaryl, wherein p is from 0-11, and wherein Y is a polymerizable group, or a monomer comprising an ion having the structure

wherein each R3group independently is H, C1-C6 alkyl, C1-C6 fluoroalkyl, aryl, or fluoroaryl, wherein p is from 0-11, wherein Y is a polymerizable group, and wherein Q is a counter ion, or a monomer comprising an ion having the structure

wherein p is from 0-11, wherein Y is a polymerizable group, and wherein Q is a counter ion, or a monomer comprising an ion having the structure

wherein each R4group independently is H, C1-C6 alkyl, C1-C6 fluoroalkyl, aryl, or fluoroaryl, wherein each u is independently from 0-10, wherein Y is a polymerizable group, wherein Z is an anionic group or a polymerizable group, and wherein Q is a counter ion, and a monomer comprising a fluorine having the structure

wherein each X is individually CF2or O, wherein each Y is polymerizable group, wherein n is from 0-100, wherein o is from 0-100, and wherein each m is individually from 1-30.

Also disclosed here is a membrane comprising a fluorinated ionic polymer network disclosed herein

DETAILED DESCRIPTION

Although any methods and materials similar or equivalent to those described herein can be used in the practice or testing of the present invention, example methods and materials are now described.

As used herein, nomenclature for compounds, including organic compounds, can be given using common names, IUPAC, IUBMB, or CAS recommendations for nomenclature. When one or more stereochemical features are present, Cahn-Ingold-Prelog rules for stereochemistry can be employed to designate stereochemical priority, E/Z specification, and the like. One of skill in the art can readily ascertain the structure of a compound if given a name, either by systemic reduction of the compound structure using naming conventions, or by commercially available software, such as CHEMDRAW™ (Cambridgesoft Corporation, U.S.A.).

As used in the specification and the appended claims, the singular forms “a,” “an” and “the” include plural referents unless the context clearly dictates otherwise. Thus, for example, reference to “a component,” “a polymer,” or “a particle” includes mixtures of two or more such components, polymers, or particles, and the like.

The term “stable,” as used herein, refers to compositions that are not substantially altered when subjected to conditions to allow for their production, detection, and, in certain aspects, their recovery, purification, and use for one or more of the purposes disclosed herein.

As used herein, the term “derivative” refers to a compound having a structure derived from the structure of a parent compound (e.g., a compound disclosed herein) and whose structure is sufficiently similar to those disclosed herein and based upon that similarity, would be expected by one skilled in the art to exhibit the same or similar activities and utilities as the claimed compounds, or to induce, as a precursor, the same or similar activities and utilities as the claimed compounds. Exemplary derivatives include salts, esters, amides, salts of esters or amides, and N-oxides of a parent compound. One ordinary skill in the art would understand the structure of a derivative, such as a cholesterol derivative.

As used herein, the term “polymer” refers to a relatively high molecular weight organic compound, natural or synthetic, whose structure can be represented by a repeated small unit, the monomer (e.g., polyethylene, rubber, cellulose). Synthetic polymers are typically formed by addition or condensation polymerization of monomers.

As used herein, the term “homopolymer” refers to a polymer formed from a single type of repeating unit (monomer residue).

As used herein, the term “copolymer” refers to a polymer formed from two or more different repeating units (monomer residues). By way of example and without limitation, a copolymer can be an alternating copolymer, a random copolymer, a block copolymer, or a graft copolymer. It is also contemplated that, in certain aspects, various block segments of a block copolymer can themselves comprise copolymers.

As used herein, the term “oligomer” refers to a relatively low molecular weight polymer in which the number of repeating units is between two and ten, for example, from two to eight, from two to six, or from two to four. In one aspect, a collection of oligomers can have an average number of repeating units of from about two to about ten, for example, from about two to about eight, from about two to about six, or form about two to about four.

As used herein, the term “cross-linked polymer” refers to a polymer having bonds linking one polymer chain to another.

The term “alkyl” as used herein is a branched or unbranched saturated hydrocarbon group of 1 to 24 carbon atoms, such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, s-butyl, t-butyl, n-pentyl, isopentyl, s-pentyl, neopentyl, hexyl, heptyl, octyl, nonyl, decyl, dodecyl, tetradecyl, hexadecyl, eicosyl, tetracosyl, and the like. The alkyl group can be cyclic or acyclic. The alkyl group can be branched or unbranched. The alkyl group can also be substituted or unsubstituted. For example, the alkyl group can be substituted with one or more groups including, but not limited to, alkyl, cycloalkyl, alkoxy, amino, ether, halide, hydroxy, nitro, silyl, sulfo-oxo, or thiol, as described herein. A “lower alkyl” group is an alkyl group containing from one to six (e.g., from one to four) carbon atoms. Non-limiting examples of alkyls include C1-18 alkyl, C1-C12 alkyl, C1-C8 alkyl, C1-C6 alkyl, C1-C3 alkyl, and C1 alkyl.

The terms “amine” or “amino” as used herein are represented by the formula — NA1A2, where A1and A2can be, independently, hydrogen or alkyl, cycloalkyl, alkenyl, cycloalkenyl, alkynyl, cycloalkynyl, aryl, or heteroaryl group as described herein.

The term “ester” as used herein is represented by the formula —OC(O)A1or —C(O)OA1, where A1can be alkyl, cycloalkyl, alkenyl, cycloalkenyl, alkynyl, cycloalkynyl, aryl, or heteroaryl group as described herein. The term “polyester” as used herein is represented by the formula —(A1O(O)C-A2-C(O)O)a— or —(A1O(O)C-A2-OC(O))a—, where A1and A2can be, independently, an alkyl, cycloalkyl, alkenyl, cycloalkenyl, alkynyl, cycloalkynyl, aryl, or heteroaryl group described herein and “a” is an integer from 1 to 500. “Polyester” is used to describe a group that is produced by the reaction between a compound having at least two carboxylic acid groups with a compound having at least two hydroxyl groups.

The term “azide” as used herein is represented by the formula —N3.

The terms per- and poly fluorinated alkyl substances (PFAS) and polyfluorinated alkyl compounds are used interchangeably herein.

PFAS contaminate ground, surface, and finished drinking water internationally. Their ecological persistence and adverse human health effects demand effective remediation approaches. Disclosed herein are materials, polymers, and methods that effectively remove a polyfluorinated alkyl compound from water. Polyfluorinated alkyl compounds can have chemically diverse structures and the disclosed materials, polymers, and methods can remove these chemically diverse structures of polyfluorinated alkyl compounds from water.

Disclosed herein are materials that utilizes both fluorophilic sorption and targeted ion exchange for the removal of polyfluorinated alkyl compounds from water. The materials, polymers, and methods disclosed herein leverages the fluorophilicity of the polyfluorinated alkyl compounds to selectively partition these micropollutants into a resin. The materials, polymers, and methods disclosed herein can utilize a tunable density of charged functional groups that can enable ion exchange and sequestration of charged polyfluorinated alkyl compounds.

Disclosed herein is a method of removing a polyfluorinated alkyl compound from water, the method comprising absorbing the polyfluorinated alkyl compound from the water with a fluorinated ionic polymer network. As disclosed herein, the fluorinated ionic polymer network utilizes both fluorophilic sorption and targeted ion exchange for the removal of polyfluorinated alkyl compounds from water.

In one aspect, the polyfluorinated alkyl compound is a short chain polyfluorinated alkyl compound having from 2 to 6 carbon atoms. In another aspect, the polyfluorinated alkyl compound is a long chain polyfluorinated alkyl compound having from 7 to 50 carbon atoms.

In one aspect, prior to performing the method the water has a concentration of the polyfluorinated alkyl compound from 2 to 500,000 ng/L. For example, the water can have a concentration of the polyfluorinated alkyl compound from 50 to 500,000 ng/L. In another example, the water can have a concentration of the polyfluorinated alkyl compound from 100 to 500,000 ng/L. In yet another example, the water can have a concentration of the polyfluorinated alkyl compound from above 140 to 500,000 ng/L. In yet another example, the water can have a concentration of the polyfluorinated alkyl compound from 150 to 500,000 ng/L. In yet another example, the water can have a concentration of the polyfluorinated alkyl compound from 300 to 500,000 ng/L. In yet another example, the water can have a concentration of the polyfluorinated alkyl compound from 500 to 500,000 ng/L. In yet another example, the water can have a concentration of the polyfluorinated alkyl compound from 1,000 to 500,000 ng/L. In yet another example, the water can have a concentration of the polyfluorinated alkyl compound from 10,000 to 500,000 ng/L. In yet another example, the water can have a concentration of the polyfluorinated alkyl compound from 2 to 100,000 ng/L. In yet another example, the water can have a concentration of the polyfluorinated alkyl compound from 2 to 10,000 ng/L. In yet another example, the water can have a concentration of the polyfluorinated alkyl compound from 2 to 1,000 ng/L. In yet another example, the water can have a concentration of the polyfluorinated alkyl compound from 2 to 500 ng/L. In yet another example, the water can have a concentration of the polyfluorinated alkyl compound from 50 to 5,000 ng/L. In yet another example, the water can have a concentration of the polyfluorinated alkyl compound from above 140 to 5,000 ng/L. In yet another example, the water can have a concentration of the polyfluorinated alkyl compound from 150 to 5,000 ng/L. In yet another example, the water can have a concentration of the polyfluorinated alkyl compound from 150 to 1,000 ng/L.

In one aspect, the method disclosed herein can remove at least 60% of the polyfluorinated alkyl compound from the water. For example, the method disclosed herein can remove at least 65% of the polyfluorinated alkyl compound from the water. In another example, the method disclosed herein can remove at least 70% of the polyfluorinated alkyl compound from the water. In yet another example, the method disclosed herein can remove at least 75% of the polyfluorinated alkyl compound from the water. In yet another example, the method disclosed herein can remove at least 80% of the polyfluorinated alkyl compound from the water. In yet another example, the method disclosed herein can remove at least 85% of the polyfluorinated alkyl compound from the water. In yet another example, the method disclosed herein can remove at least 90% of the polyfluorinated alkyl compound from the water. In yet another example, the method disclosed herein can remove at least 95% of the polyfluorinated alkyl compound from the water. In yet another example, the method disclosed herein can remove at least 97% of the polyfluorinated alkyl compound from the water. In yet another example, the method disclosed herein can remove at least 99% of the polyfluorinated alkyl compound from the water.

In one aspect, the polyfluorinated alkyl compound is dissolved in the water prior to performing the method.

In one aspect, the method further comprises the step of removing the fluorinated ionic polymer network comprising the absorbed polyfluorinated alkyl compound from the water. As such, the removed polyfluorinated alkyl compound is no longer present in the water, either as dissolved in the water or as absorbed in the fluorinated ionic polymer network. Removing the fluorinated ionic polymer network comprising the absorbed polyfluorinated alkyl compound from the water can be done via filtration, where the fluorinated ionic polymer network comprising the absorbed polyfluorinated alkyl compound from the water is filtered from the water. In another aspect, the fluorinated ionic polymer network is a filter or a part of a filter where water containing the polyfluorinated alkyl compound is filtered through the fluorinated ionic polymer network to remove the polyfluorinated alkyl compound.

In one aspect, the method further comprises the step of separating the absorbed polyfluorinated alkyl compound from the fluorinated ionic polymer network. As such, the fluorinated ionic polymer network is regenerated and can be used again to absorb more polyfluorinated alkyl compound from water. In one aspect, the fluorinated ionic polymer network can be regenerated from 2 to 100 times, such as from 2 to 50 times, or from 2 to 25 times.

The fluorinated ionic polymer network can have a positive, negative, or both positive and negative charge. As such, in one aspect, the fluorinated ionic polymer network can be a fluorinated cationic polymer network. In another aspect, the fluorinated ionic polymer network can be a fluorinated anionic polymer network. In one aspect, the fluorinated ionic polymer network can be a fluorinated polymer network that comprises both a cation and an anion. For example, the fluorinated polymer network that comprises both a cation and an anion can comprise a quaternary ammonium and a sulfonate. In yet another aspect, the fluorinated ionic polymer network is a fluorinated zwitterionic polymer network.

The fluorinated ionic polymer network can be made as a network without being ionic, and the ionic species can be from the fluorinated polymer network, thereby generating the fluorinated ionic polymer network. In one aspect, the fluorinated ionic polymer network can be a co-polymer made from a monomer comprising fluorine and a monomer comprising an ion-generating moiety. The ion-generating moiety can be made into an ionic species once the fluorinated polymer network is formed, thereby producing the fluorinated ionic polymer network.

The ion-generating moiety can be any moiety capable of being converted to an ion. In one aspect, the ion is a cation. In one aspect, the ion-generating moiety can be an amine, imidazole, benzimidazole, guanidinium, triazole, pyridine, diazine, triazine, thiol, thioether, phosphorane, or phosphine. For example, the ion-generating moiety can be an amine. For example, the amine can be a tertiary amine that is converted to a quaternary ammonium, for example, via a methylation step. In another example, the ion-generating moiety can be an imidazole. In another example, the ion-generating moiety can be a pyridine. In another example, the ion-generating moiety can be a benzimidazole. In another example, the ion-generating moiety can be a guanidinium. In another example, the ion-generating moiety can be a triazole. In another example, the ion-generating moiety can be a pyridine. In another example, the ion-generating moiety can be a diazine. In another example, the ion-generating moiety can be a triazine. In another example, the ion-generating moiety can be a thiol. In another example, the ion-generating moiety can be a thioether. In another example, the ion-generating moiety can be a phosphorane. In another example, the ion-generating moiety can be a phosphine. In another aspect, the ion is an anion. In one aspect, the ion-generating moiety can be a carboxyl, phorporic, or sulfonic group that can be converted to a carboxylate, phosphate, or sulfonate, respectively.

The fluorinated ionic polymer network can also be made directly from a polymerization where an ionic monomer is used. In one aspect, the fluorinated ionic polymer network is a co-polymer made from a monomer comprising fluorine and a monomer comprising an ion. In one aspect, the monomer comprising an ion can be a monomer comprising a cation. For example, the monomer comprising a cation can comprise a quaternary ammonium or a quaternary phosphonium. In one aspect, the monomer comprising an ion can be a monomer comprising an anion.

In one aspect, the fluorinated ionic polymer network can be a co-polymer made froma) a monomer comprising an ion generating moiety or a monomer comprising an ion; andb) a monomer comprising a fluorine having the structure

wherein each X is individually CF2or O,wherein each Y is polymerizable group,wherein n is from 0-100,wherein o is from 0-100, andwherein each m is individually from 1-30.

In one aspect, the fluorinated ionic polymer network can be a co-polymer made froma) a monomer comprising an ion generating moiety; andb) a monomer comprising a fluorine having the structure

wherein each X is individually CF2or O,wherein each Y is polymerizable group,wherein n is from 0-100,wherein o is from 0-100, andwherein each m is individually from 1-30.

In one aspect, the fluorinated ionic polymer network can be a co-polymer made froma) or a monomer comprising an ion; andb) a monomer comprising a fluorine having the structure

wherein each X is individually CF2or O,wherein each Y is polymerizable group,wherein n is from 0-100,wherein o is from 0-100, andwherein each m is individually from 1-30.

In one aspect, the monomer comprising a fluorine has the structure

In one aspect, the monomer comprising a fluorine has the structure

In one aspect, the monomer comprising a fluorine has the structure

In one aspect, the monomer comprising a fluorine has the structure

In one aspect, the monomer comprising a fluorine has the structure

In one aspect, the monomer comprising a fluorine has the structure

In one aspect, the monomer comprising a fluorine has the structure

In one aspect, the monomer comprising a fluorine has the structure

In one aspect, the monomer comprising a fluorine has the structure

In one aspect, the monomer comprising a fluorine has the structure

In one aspect, x is CF2. In another aspect, x is O. In yet another aspect, x is S. In yet another aspect, x is N—R5, wherein R5is H, alkyl, or aryl. For example, R5can be H. In another example, R5can be alkyl, such as C1-C6 alkyl, for example C1-C3 alkyl. In another example, R5can be aryl, for example C6 aryl.

In one aspect, Y is polymerizable group comprising a double bond. In another example, Y is polymerizable group comprising a vinyl group. Polymerizable groups containing vinyl groups, or other double bonds are known in the art. In another example, Y is polymerizable group selected from acrylate, methacrylate, acrylamide, methacrylamide, vinylcarbonate, vinylcarbamate, vinyl ester, vinyl benzyl, vinyl halobenzyl, vinyl ether, epoxide, oxirane, hydroxyl, or isocyanate. For example, the vinyl benzyl can be styrene. For example, the vinyl halobenzyl can be fluorinated styrene.

In one aspect, the monomer comprising fluorine can have the structure

wherein q is from 5-15, and wherein r is from 2-10. For example, q can be 9 and r can be 5. In another example, q can be from 7-11 and r can be 3-7.

In one aspect, the monomer comprising fluorine can have the structure

In one aspect, the monomer comprising an ion generating moiety can have the structure

wherein each R1group independently is H or C1-C3 alkyl. For example, each R1group can independently be C1-C3 alkyl. In another example, each R1group can be C1 alkyl. In another example, one R1group can be H and the other R1group can be C1-C3 alkyl.

In one aspect, the monomer comprising fluorine can have the structure

wherein q is from 5-15, and wherein r is from 2-10, and the monomer comprising an ion generating moiety can have the structure

wherein each Ri group independently is H or C1-C3 alkyl.

In one aspect, the monomer comprising an ion generating moiety can have the structure

wherein each R2group independently is H, C1-C6 alkyl, C1-C6 fluoroalkyl, aryl, or fluoroaryl, wherein p is from 0-11, and wherein Y is a polymerizable group. Y is a polymerizable group as disclosed elsewhere herein. In one aspect, p can be 0. In another aspect, p can be 1-11. For example, p can be 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, or 11. For example, each R2group independently can be C1-C6 alkyl, C1-C6 fluoroalkyl, aryl, or fluoroaryl, such as, C1-C6 alkyl, for example, C1 alkyl. In another example, one R2group can be H and the other R2group can be C1-C6 alkyl, C1-C6 fluoroalkyl, aryl, or fluoroaryl, such as, C1-C6 alkyl, for example, C1 alkyl.

In one aspect, the monomer comprising fluorine can have the structure

wherein q is from 5-15, and wherein r is from 2-10,
and the monomer comprising an ion generating moiety can have the structure

wherein each R2group independently is H, C1-C6 alkyl, C1-C6 fluoroalkyl, aryl, or fluoroaryl, wherein p is from 0-11, and wherein Y is a polymerizable group.

In one aspect, the monomer comprising an ion has the structure

wherein each R3group independently is H, C1-C6 alkyl, C1-C6 fluoroalkyl, aryl, or fluoroaryl, wherein p is from 0-11, wherein Y is a polymerizable group, and wherein Q is a counter ion. Y is a polymerizable group as disclosed elsewhere herein. In one aspect, p can be 0. In another aspect, p can be 1-11. For example, p can be 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, or 11. For example, each R3group independently can be C1-C6 alkyl, C1-C6 fluoroalkyl, aryl, or fluoroaryl, such as, C1-C6 alkyl, for example, C1 alkyl. In another example, one R3group can be H and the other two R3groups can be C1-C6 alkyl, C1-C6 fluoroalkyl, aryl, or fluoroaryl, such as, C1-C6 alkyl, for example, C1 alkyl. In another example, two R3groups can be H and the remaining R3group can be C1-C6 alkyl, C1-C6 fluoroalkyl, aryl, or fluoroaryl, such as, C1-C6 alkyl, for example, C1 alkyl.

Q can be any negatively charged counter ion as is known in the art. For example, Q can be Cl−, Br−, BF4−, or SO3−.

In one aspect, the monomer comprising an ion has the structure

wherein p is from 0-11, wherein Y is a polymerizable group, and wherein Q is a counter ion,

Q can be any positively charged counter ion as is known in the art. For example, Q can be K+or Na+.

In one aspect, the monomer comprising fluorine can have the structure

wherein q is from 5-15, and wherein r is from 2-10,
and the monomer comprising an ion has the structure

wherein each R3group independently is H, C1-C6 alkyl, C1-C6 fluoroalkyl, aryl, or fluoroaryl, wherein p is from 0-11, wherein Y is a polymerizable group, and wherein Q is a counter ion.

In one aspect, the monomer comprising an ion has the structure

wherein each R4group independently is H, C1-C6 alkyl, C1-C6 fluoroalkyl, aryl, or fluoroaryl, wherein each u is independently from 0-10, wherein Y is a polymerizable group, wherein Z is an anionic group or a polymerizable group, and wherein Q is a counter ion. Y is a polymerizable group as disclosed elsewhere herein. In one aspect, each u can be 0. In another aspect, each u can independently be can be 1-10. For example, each u can independently be 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10. When Z is defined as a polymerizable group, it can be defined the as the polymerizable group Y disclosed herein. When Z is an anionic group it can be, for example, carboxylate or sulfonate. For example, each R4group independently can be C1-C6 alkyl, C1-C6 fluoroalkyl, aryl, or fluoroaryl, such as, C1-C6 alkyl, for example, Cl alkyl. In another example, one R4group can be H and the other R4group can be C1-C6 alkyl, C1-C6 fluoroalkyl, aryl, or fluoroaryl, such as, C1-C6 alkyl, for example, C1 alkyl.

In one aspect, the fluorinated ionic polymer network is in the form of a particle. The particle can have a mean average diameter from 5 nm to 10 cm, for example, from 100 nm to 10 cm, from 1 μm to 10 cm, from 10 μm to 10 cm, from 100 μm to 10 cm, 1 cm to 10 cm, or from 5 cm to 10 cm.

In one aspect, the particle can have a size that is larger than a predetermined size, which can be based on the size of pores in a filter. For example, the filter can have a pore size of 1 μm. Thus, the particles should have a size of more than 1 μm so they can be collected by the filter.

In one aspect, the fluorinated ionic polymer network can be a membrane or part of a membrane. For example, the fluorinated ionic polymer network can be paricles that are filled into a cartlidge, a paced resin bed, a column, a water filtration device, or a sampling device.

The method disclosed herein can be performed in any body of water. For example, the body of water can be a natural body of water, such as a lake, pond, stream, ocean, or a manmade body of water, such as a treatment plant, pool, or dam.

Also disclosed herein are polymers, such as co-polymers. The co-polymers disclosed herein are useful in the methods disclosed herein. The co-polymers disclosed herein can be made via known polymerization methods, such a free-radical polymerization using an initiator, such as azoisobutylnitrile (AIBN).

Also disclosed here is a co-polymer made from:a) a monomer comprising an ion generating moiety having the structure

wherein each R2group independently is H, C1-C6 alkyl, C1-C6 fluoroalkyl, aryl, or fluoroaryl,wherein p is from 0-11, andwherein Y is a polymerizable group, ora monomer comprising an ion having the structure

wherein each R3group independently is H, C1-C6 alkyl, C1-C6 fluoroalkyl, aryl, or fluoroaryl,wherein p is from 0-11,wherein Y is a polymerizable group, andwherein Q is a counter ion, ora monomer comprising an ion having the structure

wherein p is from 0-11, wherein Y is a polymerizable group, and wherein Q is a counter ion, ora monomer comprising an ion having the structure

wherein each R4group independently is H, C1-C6 alkyl, C1-C6 fluoroalkyl, aryl, or fluoroaryl,wherein each u is independently from 0-10,wherein Y is a polymerizable group,wherein Z is an anionic group or a polymerizable group, andwherein Q is a counter ion, andb) a monomer comprising a fluorine having the structure

wherein each X is individually CF2or O,wherein each Y is polymerizable group,wherein n is from 0-100,wherein o is from 0-100, andwherein each m is individually from 1-30.

In one aspect, the monomer comprising a fluorine has the structure

In one aspect, the monomer comprising a fluorine has the structure

In one aspect, the monomer comprising a fluorine has the structure

In one aspect, the monomer comprising a fluorine has the structure

In one aspect, the monomer comprising a fluorine has the structure

In one aspect, the monomer comprising a fluorine has the structure

In one aspect, the monomer comprising a fluorine has the structure

In one aspect, the monomer comprising a fluorine has the structure

In one aspect, the monomer comprising a fluorine has the structure

In one aspect, the monomer comprising a fluorine has the structure

In one aspect, x is CF2. In another aspect, x is O. In yet another aspect, x is S. In yet another aspect, x is N—R5, wherein R5is H, alkyl, or aryl. For example, R5can be H. In another example, R5can be alkyl, such as C1-C6 alkyl, for example C1-C3 alkyl. In another example, R5can be aryl, for example C6 aryl.

In one aspect, Y is polymerizable group comprising a double bond. In another example, Y is polymerizable group comprising a vinyl group. Polymerizable groups containing vinyl groups, or other double bonds are known in the art. In another example, Y is polymerizable group selected from acrylate, methacrylate, acrylamide, methacrylamide, vinylcarbonate, vinylcarbamate, vinyl ester, vinyl benzyl, vinyl halobenzyl, vinyl ether, epoxide, oxirane, hydroxyl, or isocyanate.

In one aspect, the monomer comprising fluorine can have the structure

wherein q is from 5-15, and wherein r is from 2-10. For example, q can be 9 and r can be 5. For example, q can be from 7-11 and r can be from 3-7.

In one aspect, the monomer comprising fluorine can have the structure

In one aspect, the monomer comprising an ion generating moiety can have the structure

wherein each R2group independently is H, C1-C6 alkyl, C1-C6 fluoroalkyl, aryl, or fluoroaryl, wherein p is from 0-11, and wherein Y is a polymerizable group. Y is a polymerizable group as disclosed elsewhere herein. In one aspect, p can be 0. In another aspect, p can be 1-11. For example, p can be 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, or 11. For example, each R2group independently can be C1-C6 alkyl, C1-C6 fluoroalkyl, aryl, or fluoroaryl, such as, C1-C6 alkyl, for example, C1 alkyl. In another example, one R2group can be H and the other R2group can be C1-C6 alkyl, C1-C6 fluoroalkyl, aryl, or fluoroaryl, such as, C1-C6 alkyl, for example, C1 alkyl.

In one aspect, the monomer comprising an ion has the structure

wherein each R3group independently is H, C1-C6 alkyl, C1-C6 fluoroalkyl, aryl, or fluoroaryl, wherein p is from 0-11, wherein Y is a polymerizable group, and wherein Q is a counter ion. Y is a polymerizable group as disclosed elsewhere herein. In one aspect, p can be 0. In another aspect, p can be 1-11. For example, p can be 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, or 11. For example, each R3group independently can be C1-C6 alkyl, C1-C6 fluoroalkyl, aryl, or fluoroaryl, such as, C1-C6 alkyl, for example, C1 alkyl. In another example, one R3group can be H and the other two R3groups can be C1-C6 alkyl, C1-C6 fluoroalkyl, aryl, or fluoroaryl, such as, C1-C6 alkyl, for example, C1 alkyl. In another example, two R3groups can be H and the remaining R3group can be C1-C6 alkyl, C1-C6 fluoroalkyl, aryl, or fluoroaryl, such as, C1-C6 alkyl, for example, C1 alkyl.

In one aspect, the monomer comprising an ion has the structure

wherein p is from 0-11, wherein Y is a polymerizable group, and wherein Q is a counter ion. Y is a polymerizable group as disclosed elsewhere herein. In one aspect, p can be 0. In another aspect, p can be 1-11. For example, p can be 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, or 11.

In one aspect, the monomer comprising an ion has the structure

wherein each R3group independently is H, C1-C6 alkyl, C1-C6 fluoroalkyl, aryl, or fluoroaryl, wherein p is from 0-11, wherein Y is a polymerizable group, and wherein Q is a counter ion. Y is a polymerizable group as disclosed elsewhere herein. In one aspect, p can be 0. In another aspect, p can be 1-11. For example, p can be 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, or 11. For example, each R3group independently can be C1-C6 alkyl, C1-C6 fluoroalkyl, aryl, or fluoroaryl, such as, C1-C6 alkyl, for example, C1 alkyl. In another example, one R3group can be H and the other two R3groups can be C1-C6 alkyl, C1-C6 fluoroalkyl, aryl, or fluoroaryl, such as, C1-C6 alkyl, for example, C1 alkyl. In another example, two R3groups can be H and the remaining R3group can be C1-C6 alkyl, C1-C6 fluoroalkyl, aryl, or fluoroaryl, such as, C1-C6 alkyl, for example, C1 alkyl.

In one aspect, the monomer comprising an ion has the structure

wherein each R4group independently is H, C1-C6 alkyl, C1-C6 fluoroalkyl, aryl, or fluoroaryl, wherein each u is independently from 0-10, wherein Y is a polymerizable group, wherein Z is an anionic group or a polymerizable group, and wherein Q is a counter ion. Y is a polymerizable group as disclosed elsewhere herein. In one aspect, each u can be 0. In another aspect, each u can independently be can be 1-10. For example, each u can independently be 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10. When Z is defined as a polymerizable group, it can be defined the as the polymerizable group Y disclosed herein. When Z is an anionic group it can be, for example, carboxylate or sulfonate. For example, each R4group independently can be C1-C6 alkyl, C1-C6 fluoroalkyl, aryl, or fluoroaryl, such as, C1-C6 alkyl, for example, C1 alkyl. In another example, one R4group can be H and the other R4group can be C1-C6 alkyl, C1-C6 fluoroalkyl, aryl, or fluoroaryl, such as, C1-C6 alkyl, for example, C1 alkyl.

In one aspect, if the co-polymer comprises the monomer comprising an ion generating moiety, then the monomer comprising an ion generating moiety is ionized.

In one aspect, the co-polymer is in the form of a particle. The particle can have a mean average diameter from 5 nm to 10 cm, for example, from 100 nm to 10 cm, from 1 μm to 10 cm, from 10 μm to 10 cm, from 100 μm to 10 cm, 1 cm to 10 cm, or from 5 cm to 10 cm.

In one aspect, the particle can have a size that is larger than a predetermined size, which can be based on the size of pores in a filter. For example, the filter can have a pore size of 1 μm. Thus, the particles should have a size of more than 1 μm so they can be collected by the filter.

In one aspect, the fluorinated ionic polymer network can be a membrane or part of a membrane. For example, the fluorinated ionic polymer network can be particles that are filled into a cartlidge, a paced resin bed, a column, a water filtration device, or a sampling device.

A membrane comprising an fluorinated ionic polymer network disclosed herein.

1. Materials and Instrumentation

Materials: All materials purchased from commercial source was used as received without further purification unless otherwise mentioned. Perfluoropolyether Fluorolink® MD700 (Mwt: 1.8-2.0 kg·mol−1) was purchased from Solvay Solexis. 2-(dimethylamino)ethyl methacrylate, Poly(ethylene glycol) dimethacrylate (average Mn 750), azobisisobutyronitrile (AIBN), humic acid and perfluorooctanoic acid (PFOA) was purchased from Sigma-Aldrich. Trifluoroethanol was purchased Synquest labs. Perfluorohexanoic acid (PFHxA) and GenX were purchased from TCI and Matrix respectively.

Instrumentation: LCMS: Water samples were stored under refrigeration until analysis. A 196 μL aliquot of sample and 4 μL of stable isotope-labeled analogues (Wellington Labs, Guelph, Calif., product numbers MPFAC-C-ES and M3HFPO-DA) were transferred to polypropylene autosampler vials and closed with caps fitted with silicone septa. No other processing was done as per a direct injection method by Sun, M. et al.,Environ. Sci. Technol. Lett.2016, 3, 415-419.

Analysis of target compounds was performed using an Accela HPLC system coupled to a TSQ-Quantum Ultra triple-quadrupole mass analyzer (Thermo Scientific, San Jose, Calif.) operated in negative ion mode. Samples were chromatographed on a 3.0×50 mm Poroshell C18 2.7 μm column (Agilent Technologies, Santa Clara, Calif.) with gradient elution at a flow rate of 350 μL per min. Binary mobile phase consisted of 95:5:water:methanol containing 2 mM ammonium acetate (A) and 5:95:water:methanol containing 2 mM ammonium acetate (B). Composition started at 25% B, was held for 0.5 min., increased linearly to 90% B over 2 min., was held at 90% B for 1.5 min., decreased linearly to 25% B over 0.1 min., and held at 25% B for 0.9 min for column equilibration. Mass spectrometer parameters were as follows: spray voltage of 3000 V, vaporizer temperature of 150° C., sheath gas flow rate 40, auxiliary gas flow rate 20, capillary temperature of 225° C., argon collision gas pressure of 1.0 mTorr, 0.05 sec per scan, quadrupole 1 resolution of 0.5 amu, quadrupole 3 resolution of 0.7 amu and collision energy 10 eV. Mass transitions and other compound-specific parameters are listed in Table 1. The limit of detection was 2 pg per 100 μL (20 pg/mL) injection for each analyte. Linear or quadratic calibration curves using the analyte to internal standard ratio were used to calculate analyte amounts. Calibration points were 2, 10, 50, 200, and 1000 pg analyte versus 50 pg internal standard for PFCAs and PFASs.

Thermal gravimetric analysis (TGA) was performed on a TA Instruments TGA (Discovery Series) using 5-8 mg of the sample. The samples were heated to 25-600° C. at a temperature ramp rate of 10° C./min. Infrared (IR) spectra were obtained using PerkinElmer Frontier FT-IR spectrometer.

Deionized water used in this study is a type 1, 18.2 megohm-cm water obtained from Labconco—waterpro PS series. This water was amended with sodium chloride and humic acid if necessary.

Centrifugation was performed using a benchtop centrifuge—Mini mouse II by Denville.

The batch adsorption studies of mixtures of PFAS (PFOA, PFHxA and GenX) was performed in a 1 L HDPE bottle equipped with a magnetic stir bar. The mixture was stirred on a stir plate at room temperature and at 700 revolution per minute (rpm).

High Concentration (50 μg/L): To a 1L deionized water added sodium chloride (200 mg) and humic acid (20 mg) and stirred overnight. To this mixture added vacuum dried polymer adsorbent (fluorinated ionic polymer network) (10 mg L−1) and stirred at room temperature for 3 h with occasional sonication to disperse the adsorbent. A stock solution of PFAS was spiked to the mixture to create an initial concentration of 50 μg L−1of each PFAS. This mixture was stirred for 21 h after which an aliquot of about 10 mL was withdrawn and filtered through either 0.2 μm PTFE or 0.45 μm cellulose acetate filter. The first 5 mL was drained to avoid any electrostatic effect from the filter and the remaining 5 mL was collected for LCMS analysis. Control experiments to account for PFAS losses during handling were performed under identical condition in the absence of adsorbent. This batch experiment was performed only once.

Low Concentration (1 μg/L): The batch adsorption studies of PFAS under environmentally relevant concentration described below (1 μg L−1) was performed under identical condition as detailed above except that the PFAS was spiked to create an initial concentration of 1 μg L−1of each PFAS. This set of experiments were performed in triplicates.

The efficiency of PFAS removal by adsorbents discussed herein was determined by the following equation:

The amount of PFAS bound to the polymer sorbent is given by the following equation:

For the adsorption kinetic experiments disclosed herein, the following conditions were used.

High concentration (200 μg/L): The adsorption kinetic experiments were performed in 125 mL polypropylene bottle equipped with a magnetic stir bar. The experiments were performed at room temperature on a multi-position stirrer at 500 rpm. The adsorbent dose was set at 10 mg/L with total operating volume of 100 mL. The fluorinated ionic polymer network and water mixture was stirred for 3 h with occasional sonication to disperse the adsorbent before being spiked with GenX stock to create an initial concentration of 200 μg/L. About 1 mL aliquot was taken at each predetermined time intervals (0.5, 1, 5, 10, 30, 60, mins and 21, 48 and 72 h). The aliquots were centrifuged for 15 minutes and the supernatant was analyzed by LCMS to determine the residual GenX concentration. Control experiments to account for GenX losses during handling were performed under identical condition in the absence of adsorbent. This batch kinetics experiment was performed in triplicates.

Low concentration (1 μg/L): About 5 mg of fluorinated ionic polymer network was taken in an 8 mL vial, followed by addition of DI water to create a concentration of 1 mg/mL. The mixture was subjected to series of vortex and sonication to completely disperse fluorinated ionic polymer network. 1 mL of this mixture was taken while under constant mixing and added to 99 mL of water in a polypropylene bottle (125 mL) equipped with a magnetic stir bar. The mixture was stirred at 500 rpm for 3 h before being spiked with GenX stock to create an initial concentration of 1 μg/L. About 1 mL aliquot was taken at each predetermined time intervals (0.5, 1, 3, 5, 10, 20, 30, 60, 120, 240 mins and 21, 48 and 72 h). The aliquots were centrifuged for 15 minutes and the supernatant was analyzed by LCMS to determine the residual GenX concentration. Control experiments to account for GenX losses during handling were performed under identical condition in the absence of adsorbent. This batch kinetics experiment was performed in triplicates.

The kinetics of adsorption can be described with Ho and McKay's linearized form of pseudo-second-order adsorption model given by following equation (Ho, Y. et al.,Process Biochem.1999, 34, 451-465):

For the binding isotherm experiments disclosed herein, the following conditions were used.

The batch isotherm studies were performed in 125 mL polypropylene bottles (100 mL operating volume) containing magnetic stir bar on a multi-position stirrer at 23-25° C. at 500 rpm. The deionized water containing fluorinated ionic polymer network adsorbent (100 mg/L) was stirred for 3 h before the GenX addition. A stock solution of GenX was spiked to create initial concentrations of 0.2, 1, 5, 10, 20, 30 and 50 mg/L. The suspension was stirred for 21 h to reach equilibrium and an aliquot was taken in a centrifuge tube. The aliquots were centrifuged for 15 minutes and the supernatant from the top was taken for LCMS analysis. High concentration samples were serial diluted (5-10 mg/L diluted 20× and 20-50 mg diluted 100×) before LCMS analysis. Control experiments in the absence of adsorbent were performed under identical conditions to account for handling losses. All the batch experiments were carried out in triplicates.

Langmuir adsorption and Freundlich isotherm fits were generated by Non-linear Least Square Regression of the following equation. Langmuir adsorption isotherm:

A preliminary fit was generated using linearized equations of Langmuir (1/qevs 1/Ce) and Freundlich (1 n qevs 1n Ce) adsorption isotherm and the obtained values were used as a starting point for non-linear least square regression analysis. Table 1 shows the Langmuir and Freundlich parameters derived from linearized plots of the GenX binding isotherm. In Table 1 IF-20 and IF-30 represents networks with fluorolink (80% and 70%) and 2-(dimethylamino)ethyl methacrylate (20% and 30%), respectively.

5. Natural Water Experiments

For the natural water experiments disclosed herein, the following conditions were used.

The adsorption kinetic experiments were performed in 500 mL polypropylene bottles equipped with a magnetic stir bar. The experiments were performed at room temperature on magnetic stirrers. The adsorbent dose was set at 100 mg/L with a total operating volume of 400 mL. The fluorinated ionic polymer network was soaked in 5 ml of water for 3 days with occasional sonication do disperse the adsorbent before being adding to the 1 ug/L PFAS spiked water. About 10 mL aliquot was taken at each predetermined time intervals (0, 30, 60 and 120 mins). The aliquots were filtered through pre-washed 0.45 um glass fiber syringe filter and the filtered solution was analyzed by LCMS to determine the residual PFAS concentration. Two control experiments to account for PFAS losses and PFAS contaminations during handling were performed under an identical condition in the absence of adsorbent and Deionized water. This batch kinetics experiment was performed in duplicate.

6. Adsorption and Regeneration Experiments

For the adsorption and regeneration experiments disclosed herein, the following conditions were used.

Adsorption experiment: Fluorinated ionic polymer network IF-20 (20 mg) was suspended in deionized water (5 mL) followed by series of sonication and vortexing for 5 mins to disperse the adsorbent. The resulting suspension was passed through 20 mL syringe fitted with 0.45 μm PTFE filter (25 mm), additional water was used if necessary. A solution of GenX (10 mg L−1, 20 mL) was passed through the filter over 2 mins and the resultant filtrate was collected in a polypropylene tube. The change in GenX concentration in the filtrate was measured by LC-MS. The PTFE filter was washed by passing through deionized water (20 mL) to remove any trace of GenX solution left over and the residual deionized water was removed by vacuum suction.

Desorption experiment: The PTFE filter containing GenX was extracted by passing through a methanolic solution appended with 400 mM ammonium acetate (20 mL) over 2 minutes. The concentration of extracted GenX was analyzed by LC-MS. The PTFE filter was washed by passing through deionized water (20 mL) to remove any trace of methanolic solution left over and the residual deionized water was removed by vacuum suction.

The adsorption-desorption cycle was extended to 5 cycles to demonstrate the recyclability of the fluorinated ionic polymer network without the loss of efficiency.

An illustrative procedure for the synthesis for a fluorinated ionic polymer network with fluorolink (80%) and 2-(dimethylamino)ethyl methacrylate (20%) is provided below. To a 20 mL scintillation vial with green top cap equipped with magnetic stir bar added perfluoropolyether Fluorolink MD700 (1.6 g, 80 wt %), 2-(dimethylamino)ethyl methacrylate (0.4 g, 20 wt %), azobisisobutyronitrile (20 mg, 1 wt %) and trifluoroethanol (2.0 g, 1×). The vial was closed and bubbled with nitrogen for 5 minutes and heated in an aluminum block at 70° C. for 5 h stirring at 200-300 rpm. Within 15 mins, fluorinated ionic polymer network particles were observed and within 1 h the entire mixture was gelled. After the reaction, the mixture was cooled to room temperature and the fluorinated ionic polymer network was hand crushed to fine powder. To this powder, additional trifluoroethanol (10 mL) and iodomethane (2 mL) was added and the mixture was stirred at room temperature for 24 h. The content of the vial was transferred to teabag and ethanol was used to transfer if needed. The fluorinated ionic polymer network was washed with ethanol using Soxhlet extraction set up for 24 h. Finally, the fluorinated ionic polymer network was dried under vacuum oven at 50° C. for 24 h, then passed through 125 μm and 75 μm sieves to collect particles in that range. The fluorinated ionic polymer network was obtained as a pale-yellow powder in 2.2 g yield.

To obtain the fluorinated ionic polymer network in the form of a tertiary amine, the methylation step was not performed. Instead, after crushing, the fluorinated ionic polymer network was directly packed in teabag and purified using Soxhlet apparatus.

Other formulations of fluorinated ionic polymer networks containing varying amount of amine/ammonium derivatives were prepared by adding appropriate amount of amine and Fluorolink MD700 using the procedure above. For instance, to make a fluorinated ionic polymer network with fluorolink (70%) and 2-(dimethylamino)ethyl methacrylate (30%), 1.4 g of Fluorolink MD 700 and 0.6 g of 2-(dimethylamino)ethyl methacrylate (0.4 g, 30 wt %) was used (yield: 2.3 g).

Synthesis of control PEG gel: PEG gels were obtained using the same procedure as mentioned above. The fluorolink MD 700 was replaced by poly(ethylene glycol) dimethacrylate (average Mn 750). This particular molecular weight was chosen to mimic the number of atoms in the backbone between the dimethacrylate functionality of fluorolink.FIG. 5shows a TGA of IF-20 and IF-30 (IF-20=a fluorinated ionic polymer network with fluorolink (80%) and 2-(dimethylamino)ethyl methacrylate (20%); IF-30=a fluorinated ionic polymer network with fluorolink (70%) and 2-(dimethylamino)ethyl methacrylate (30%))FIG. 6shows a Fourier transform-infrared (FTIR) spectra of IF-20 and IF-30.

8. Results and Discussion

Perfluoropolyethers (PFPEs) were used as the fluorophilic matrix material in the experiments described herein (Bell, G. A.; Howell, J.Synthetics, Mineral Oils, and Bio-Based Lubricants: Chemistry and Technology;Rudnick, L. R., Ed.; CRC PRess: Boca Raton, Fla., 2005; pp 157-174). PFPEs are amorphous, low molecular weight perfluorinated oligomers that are synthesized from the gas phase without the use of perfluorinated surfactants (U.S. Pat. No. 6,753,301).

The synthesis of an exemplary fluorinated ionic polymer network was achieved through a thermally-initiated radical copolymerization initiated by azobisisobutyronitrile of a commercially available PFPE with methacrylate chain-end functionality (Fluorolink® MD 700) and an amine-containing monomer (2-dimethylaminoethyl methacrylate, DMAEMA)

The composition of DMAEMA in the exemplary fluorinated ionic polymer network was varied from 10-60% (wt %) compared to Fluorolink® to generate a systematic library of materials that varies the ratio of fluorophilic and charged components in the resin. Grinding and sieving the material provided a granular formulation with particle size between 75-125 microns for evaluation. A portion of each formulation was subsequently treated with methyl iodide to access materials with quaternary ammonium groups that act as permanent charged species of the exemplary fluorinated ionic polymer network.

This approach provides two exemplary fluorinated ionic polymer network formulations for analysis from a single polymerization of commercially available components. A library of materials was additionally prepared to act as negative controls in our structure-property studies. First, a PFPE elastomer with no electrostatic component (no DMAEMA) was made. Second, non-fluorous ionic networks with charged groups but without a fluorous component were synthesized through the radical copolymerization of polyethylene glycol dimethacrylate (PEG-DMA, Mn=750 g/mol) and DMAEMA. This particular PEG-DMA was chosen to mimic a similar degree of polymerization between crosslinks as Fluorolink® MD 700.

The PFAS removal efficiency of each exemplary fluorinated ionic polymer network formulation was tested by conducting batch equilibrium adsorption experiments in simulated groundwater, which was formulated by adding 200 mg/L NaCl and 20 mg/L humic acid to deionized water. Three PFAS that represent long chain (PFOA), short chain (perfluorohexanoic acid, PFHxA), and branched (GenX) PFAS were spiked into the matrix each at an environmentally relevant concentration (1.0 μg/L). After exposing the contaminated water sample to 10 mg/L of exemplary fluorinated ionic polymer network for 21 hours, the PFAS removal efficiency was analyzed by liquid chromatography mass spectrometry (LC-MS). The results of this systematic study revealed valuable structure-property information, seeFIGS. 1A-1F.FIG. 1Ashows equilibrium PFAS removal by fluorinated ionic polymer networks with amine (F-X) or ammonium (IF-X) groups where X=0, 20, or 30 wt %.FIG. 1Bshows equilibrium PFAS removal by GAC, PAC, IX and fluorinated ionic polymer networks (IG-X) made with a PEG-DMA, where X=20 or 30 wt %. Additives: 200 mg/L NaCl and 20 mg/L humic acid; Adsorbent: 10 mg/L; PFAS: (PFOA, PFHxA, GenX, 1 μg L−1each); Equilibrium time: 21 h. InFIGS. 1A and 1BError bars: Standard deviation of 3 experiments.

FIG. 1Dshows equilibrium PFAS removal efficiency by various compositions of fluorinated ionic polymer networks in presence of NaCl (200 ppm) and humic acid (20 ppm). PFAS: PFOA, PFHxA and GenX (each 1 μg/L). adsorbent dosage: 10 mg/L. equilibrium time: 21 h. The data points in the figure are an average of three experiments, and the error bar show their standard deviation.

FIG. 1Eshows equilibrium PFAS removal efficiency by granular activated carbon(GAC), powdered activated carbon (PAC) and ion-exchange resin (IX), in presence of NaCl (200 ppm) and humic acid (20 ppm). PFAS: PFOA, PFHxA and GenX (each 1 μg/L). adsorbent dosage: 10 mg/L. Equilibrium time: 21 h. The data points in the figure are an average of 3 experiments and the error bar show their standard deviation.

Exemplary fluorinated ionic polymer networks containing tertiary amines demonstrated lower affinity for PFAS than the respective materials that contained quaternary ammonium groups across all formulations tested, proving the importance of incorporating permanent charge. Additionally, a minimum of 20 wt % ammonium was required to demonstrate acceptable (>80%) removal of short-chain PFAS, PFHxA, and GenX.

Comparing exemplary fluorinated ionic polymer networks against materials made to serve as controls illustrated the synergistic roles of fluorous interactions and ion exchange behavior. Removing ionic groups and exposing a fluorinated ionic polymer network made from Fluorolink® MD 700 to the equilibrium absorption experiment led to no removal of PFHxA or GenX. Furthermore, exemplary fluorinated ionic polymer networks made with a hydrocarbon equivalent of PFPEs demonstrated poor results for all formulations tested (<10% removal for all PFAS). These experiments point to the significance of incorporating both a fluorophilic matrix and ionic groups within the same fluorinated ionic polymer network.

Commercial materials previously identified for PFAS removal were subsequently tested under the described equilibrium absorption conditions. Samples of GAC (Filtrasorb 400), powdered activated carbon (PAC, PicaHydro MP23) and an anion exchange resin (PFA 694E) were exposed to simulated groundwater for 21 hours at a resin loading of 10 mg/L (Zaggia, A.,Water Res.2016, 91, 137-146). The absorption of these commercial material for short-chain PFAS is shown inFIG. 1B. These head-to-head comparisons demonstrate the selectivity of the fluorinated ionic polymer networks disclosed herein for PFAS compared to conventional technologies, particularly in a complex matrix that contains a 20,000 times higher concentration of organic contaminants (humic acid) compared to each PFAS.

GenX was chosen for the testing as an emerging short-chain contaminant to investigate the kinetics of absorption and capacity of the fluorinated ionic polymer networks disclosed herein. The formulation containing 20 wt % and 30 wt % quaternized DMAEMA compared to PFPE were investigated. The absorption kinetics of GenX at high concentration (200 μg/L) by the fluorinated ionic polymer network containing 20 wt % quaternized DMAEMA (100 mg/L) was analyzed in deionized water (seeFIGS. 2A-2G).FIG. 2Ashows time dependent GenX adsorption by a fluorinated ionic polymer network with 20 wt % quaternized DMEAMA at high (red, dashed; GenX=200 μg L−; adsorbent=100 mg L−1) and low concentration (blue; GenX=1 μg L−1; adsorbent=10 mg L−1). Error bars: Standard deviation of three experiments.FIG. 2B-2Cshow kinetics of GenX (200 μg/L) adsorption by a fluorinated ionic polymer network with 20 wt % quaternized DMEAMA (FIG. 2B) and a fluorinated ionic polymer network with 30 wt % quaternized DMEAMA (FIG. 2C). Adsorbent dosage: 100 mg/L. The data points in the figure are an average of 3 experiments and the error bar show their standard deviation.FIGS. 2D-2Eshow kinetics of GenX (1 μg/L) adsorption by a fluorinated ionic polymer network with 20 wt % quaternized DMEAMA (FIG. 2D) and a fluorinated ionic polymer network with 30 wt % quaternized DMEAMA (FIG. 2E). Adsorbent dosage: 10 mg/L. The data points in the figure are an average of 3 experiments and the error bar show their standard deviation.FIGS. 2F-2Gshow pseudo second order plots of a fluorinated ionic polymer network with 20 wt % quaternized DMEAMA (FIG. 2F) and a fluorinated ionic polymer network with 30 wt % quaternized DMEAMA (FIG. 2G). Adsorbent dosage: 10 mg/L; GenX: 1 μg/L. The data points in the figure are an average of 3 experiments and the error bar show their standard deviation.

In this system, rapid and quantitative removal of GenX was observed within 30 seconds. No desorption was observed out to 72 hours, suggesting the adsorption into the fluorinated ionic polymer network is irreversible. Similarly, the adsorption kinetics at an environmentally relevant concentration of GenX (1 μg/L) by the fluorinated ionic polymer network (10 mg/L) was also rapid, demonstrating 94% removal within 30 mins and no desorption over time (FIGS. 2A-AG). This removal efficiency for GenX results in a final concentration under the limit set by the state of North Carolina (140 ng/L).

A GenX binding isotherm was constructed to investigate the binding capacity of the fluorinated ionic polymer network containing 20 wt % quaternized DMAEMA. The concentration of the fluorinated ionic polymer network was fixed at 100 mg/L while the GenX concentration was varied from 0.20-50 mg/L. Data from triplicate experiments (seeFIG. 3A) was fit to the Langmuir adsorption model to yield an affinity coefficient (KL) of 5.9×106M−1and an estimated GenX capacity (Qm) of 278 mg/g. These represent the highest reported values in the literature for GenX. The isotherm was also fit to Freundlich model and the Freundlich's constant (KF) and the intensity of adsorption (n) were found to be 141 (mg/g) (L/mg)1/nand 2.2 respectively. Subsequently, the fluorinated ionic polymer network was tested for its ability to be regenerated for multiple reuse cycles (FIGS. 3B and 3H).

FIGS. 3C-3Dshow GenX adsorption isotherm linear fitted to Langmuir model for a fluorinated ionic polymer network with 20 wt % quaternized DMEAMA (FIG. 3C) and a fluorinated ionic polymer network with 30 wt % quaternized DMEAMA (FIG. 3D). Adsorbent dosage: 100 mg/L; [GenX]: 0.2-50 mg/L. The data points in the figure are an average of three experiments, and the error bar show their standard deviation.

FIGS. 3E-3Fshow GenX adsorption isotherm linear fitted to Freundlich model for a fluorinated ionic polymer network with 20 wt % quaternized DMEAMA (FIG. 3E) and a fluorinated ionic polymer network with 30 wt % quaternized DMEAMA (FIG. 3F). Adsorbent dosage: 100 mg/L; [GenX]: 0.2-50 mg/L. The data points in the figure are an average of 3 experiments and the error bar show their standard deviation.

FIGS. 3A and 3Gshow GenX adsorption isotherm for a fluorinated ionic polymer network with 20 wt % quaternized DMEAMA (FIG. 3A) and a with 30 wt % quaternized DMEAMA (FIG. 3G). Dotted lines represent fit to Langmuir and Freundlich models. Adsorbent dosage: 100 mg/L; [GenX]: 0.2-50 mg/L. The data points in the figure are an average of 3 experiments and the error bar show their standard deviation.

Adsorption experiments were performed by loading the fluorinated ionic polymer network containing 20 wt % quaternized DMAEMA onto a PTFE syringe filter (0.45 μm, 25 mm diameter). A GenX solution (10 mg/L, 20 mL) was passed through the filter over 2 minutes, and the residual GenX concentration in the filtrate was analyzed by LC-MS. The results showed >90% removal of GenX from the solution in such flow-through conditions, thus demonstrating the efficiency of absorption even under short residence time conditions. Complete extraction of adsorbed GenX from the fluorinated ionic polymer network was achieved by washing the material with a 400 mM methanolic ammonium acetate solution (20 mL, 2 min). This process was repeated five times without loss of efficiency in adsorption or reuse.

The tested fluorinated ionic polymer network provided rapid, efficient, and high capacity removal of a variety of PFAS under laboratory conditions. Natural water matrices, however, contains a cocktail of organic and inorganic contaminants that are difficult to model in a laboratory setting. To validate the fluorinated ionic polymer networks disclosed herein as a for PFAS removal from water, therefore, tests were conducted on settled water collected at a site previously affected by PFAS contamination, the Sweeney Water Treatment Plant in Wilmington, NC. In addition to PFAS found in the water upon collection (at levels of 20-50 ng/L), the water was spiked the matrix with 21 emerging and legacy PFAS. The natural water matrix was exposed to the fluorinated ionic polymer network containing 30 wt % quaternized DMAEMA (100 mg/L) and PFAS removal was analyzed at 30 minutes and 2 hours, with the data presented being the average of two experiments. The results show good PFAS removal after two hours, seeFIG. 4A-4B, which shows complete analysis of 21 different PFAS.

FIG. 4Ashows the removal of 10 representative PFASs after 2 hours by the fluorinated ionic polymer network containing 30 wt % quatemized DMAEMA from groundwater settled water collected at the Sweeney Water Treatment Plant in Wilmington, N.C. [Adsorbent]=100 mg L−1; [PFAS]=1 μg L−1.

Short chain PFAS that are traditionally challenging to absorb, including PFHxA, GenX, and PFBS, were removed from the water at >95% efficiency with the fluorinated ionic polymer network. No evidence of long chain PFAS such as PFOA and PFOS in the solution down to the detection limit of the LC-MS were observed. Lastly, the fluorinated ionic polymer network performed equal to or better than the previously best materials reported for removing the short chain perfluorinated carboxylic acids PFBA and PFPeA, achieving 60% and 88%, respectively, seeFIG. 4A-4B).

The fluorinated ionic polymer networks disclosed herein is a platform for polymeric adsorbent to remove PFAS from water at environmentally relevant concentrations. The synergistic combination of the fluorous and electrostatic interactions results in high affinity, high capacity, and rapid sorption of PFASs.

Drinking Water Health Advisory for Perfluorooctanoic Acid (PFOA); 2016.

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