GB2481985A

GB2481985A - Removal of fluoroorganic anions from an aqueous phase

Info

Publication number: GB2481985A
Application number: GB1011715.8A
Authority: GB
Inventors: Venkateswarlu Pothapragada; William M Lamanna; Michael D Barrera; Brian T Mader; Daniel R Vitcak; Bradford B Wright; Zongxingn Zhang
Original assignee: 3M Innovative Properties Co
Current assignee: 3M Innovative Properties Co
Priority date: 2010-07-13
Filing date: 2010-07-13
Publication date: 2012-01-18
Also published as: GB201011715D0

Abstract

A process for removing fluoroorganic anions from an aqueous phase comprises contacting the aqueous phase with an organoammonium, wherein a fluoroorganic anion from the aqueous phase and the organoammonium form a hydrophobic ion pair; and then separating the hydrophobic ion pair from the aqueous phase. The resulting aqueous phase comprises less than 1 % by weight of fluoroorganic anions. The organoammonium may be obtained by protonating an amine in situ. In another aspect, a process for removal of fluoroorganic anions from an aqueous phase comprises contacting the aqueous phase with an organic phase, wherein the organic phase comprises at least one water soluble amine, to form a mixture and agitating the mixture to extract the fluoroorganic anions into the organic phase. The mixture is then allowed to phase separate. Optionally, a base is added to the organic phase to recover the fluoroorganic anions and/or to regenerate the amine.

Description

PROCESS FOR REMOVAL OF FLUOROORGANIC ANIONS FROM AQUEOUS

SOLUTIONS

TECHNICAL FIELD

[0001] A process for removing, and optionally recovering, fluoroorganic anions from aqueous solutions using organoammonium is described.

BACKGROUND

[0002] Fluorinated compositions have been used in a wide variety of applications including fluorochemicals for: water-proofing materials, fire-fighting foams for electrical and grease fires, semi-conductor etching, and lubricants; and fluoropolymers for: hoses, gaskets, seals, coatings, and films. Reasons for such widespread use of fluorinated compositions include their favorable physical properties, which include chemical inertness, low coefficients of friction, and low polarizabilities (i.e., fluorophilicity).

[0003] After production of a fluorinated composition, fluorinated compounds, including, for example, starting materials and reaction by-products, may be removed from the waste streams generated by the production. The removal of the fluorinated compounds may be to recover expensive starting material and/or to obtain purified water for recycling back to the process or return to the environment.

[0004] Processes to remove or recovery fluorinated compounds include ion exchange, ultrafiltration, distillation, liquid-liquid extraction, reverse osmosis, and adsorption on clays, carbon and other media. Such processes have been described in U.S. Publ. Nos. 2006/0205828 (Maurer et aL), 2007/0025902 (Hintzer et al); and 2010/0084343 (Mader et al.); and U.S. Pat. Nos. 3,882,153 (Seki et al.); 4,369,266 (Kuhls, et al.); 6,642,415 (Fuhrer et al.); 7,279,522 (Dadalas et al.); and 5,603,812 (Hommeltoft).

SUMMARY

OOO5] There is a desire to find an alternative process to remove fluorinated anions from aqueous solutions, which is efficient, fast, and more simple to implement, which may enable reduced processing time and cost. There is also a desire to find a process that would enable recycling of the materials and recovery of the fluorinated anions.

[0006] In one aspect, a process for removing fluoroorganic anions from an aqueous phase is described, the process comprising: contacting the aqueous phase with an organoammonium, wherein a fluoroorganic anion from the aqueous phase and the organoammonium form a hydrophobic ionic pair; separating the hydrophobic ionic pair from the aqueous phase, wherein the resulting aqueous phase comprises less than 1 % by weight of fluoroorganic anions.

[0007] In one embodiment, aqueous phase further comprises a water soluble salt.

[0008] In another embodiment, the pH of the aqueous phase is greater than 4.

[0009] In yet another embodiment, the pH of the aqueous phase is less than 9.

[0010] In yet another embodiment, the organoammonium is derived from a water insoluble amine.

[0011] In another embodiment, the organoammonium is derived from at least one of: (i) an amine of formula (I): NR1R2R3 (I) wherein R1, R2, and R3 may be the same or different and at least one of R1, R2, and R3 is a linear or branched, saturated or unsaturated carbon group, which optionally, may comprise heteroatoms and/or functional groups, and optionally, wherein one or two of ft-R3maybeaH;and (ii) a quaternary ammonium salt of formula (II): [NR1R2R3R4]1A' (II) wherein R1, R2, R3, and R4 may be the same or different and is a linear or branched, saturated or unsaturated carbon group, which optionally, may comprise other heteroatoms and/or functional groups, and A is an anion having a valence of i, wherein i is 1,2,3, or4.

[0012] In yet another aspect, a process for removing fluoroorganic anions from an aqueous phase is described, the process comprising: contacting the aqueous phase with an organic phase comprising at least one water insoluble amine to form a mixture, agitating the mixture to extract the fluoroorganic anions into the organic phase, and allowing the mixture to phase separate.

[0013] In one embodiment, the organic phase is separated from the aqueous phase and a base is added to the organic phase to recover the fluoroorganic anions, and optionally, to regenerate the water insoluble amine.

[0014] The above summary is not intended to describe each embodiment. The details of one or more embodiments of the invention are also set forth in the description below.

Other features, objects, and advantages will be apparent from the description and from the claims.

DETAILED DESCRIPTION

[0015] As used herein, the term "a", "an", and "the" are used interchangeably and mean one or more; "and/or" is used to indicate one or both stated cases may occur, for example A and/or B includes, (A and B) and (A or B); "backbone" refers to the longest carbon chain in the compound; and "organic" has the common meaning in the art, for example, organic compounds are carbon-containing compounds with some exceptions/exclusions including: binary compounds such as carbides, carbon oxides, carbon disulfide; ternary compounds such as metallic cyanides, phosgene, carbonyl sulfide; and metallic carbonates, such as calcium carbonate.

[0016] Also herein, recitation of ranges by endpoints includes all numbers subsumed within that range (e.g., ito 10 includes 1.4, 1.9, 2.33, 5.75, 9.98, etc.).

[0017] Also herein, recitation of "at least one" includes all numbers of one and greater (e.g., at least 2, at least 4, at least 6, at least 8, at least 10, at least 25, at least 50, at least 100, etc.).

[0018] The present disclosure provides processes to facilitate the removal of fluoroorganic anions from aqueous solutions. Such processes may be used, for example, to treat waste water. In the present disclosure, the fluoroorganic anions are removed from an aqueous solution using an organoammonium compound.

[0019] The fluoroorganic anions of the present disclosure are organic and comprise at least one fluorine atom. In other words, the fluoroorganic anions include those that are fully or partially fluorinated. The fluoroorganic anion may be any fluorinated compound, as long as it ion pairs with the organoammonium and either forms a non-aqueous phase or can be extracted into a non-aqueous phase. Examples of such fluoroorganic anions include, for example, carboxylates, sulfonates, sulfinates, phosphates, imides, methides, and anions of telomer acids.

[0020] Fluoroorganic anions that may be removed by the process of the present disclosure include fluorinated starting materials and by-products from the manufacture of fluorinated compositions; and fluorinated degradation products.

[0021] In one embodiment, the fluoroorganic anion is selected from formula (III): R-Z (III) wherein 1 represents a deprotonated acid functional group such as -COO, -SO3, -SO2, -N[S(=O)2R], or -P[03R1; R is selected from hydrogen, a hydrocarbon group that may comprise heteroatoms, or R; and R is independently selected from a linear or branched, partially or fully fluorinated, saturated or unsaturated carbon group and optionally, may comprise heteroatoms (such as N, 0, or S) and/or functional groups, including additional acid functional groups (e.g., sulfonates). The number of carbons in Rican vary, including, for example carbon backbones comprising at least 1, 2, 3,4, 6, 8, 10, or 12 carbon atoms or more.

[0022] In one embodiment, the fluoroorganic anion is selected from formula (lila): R-O-L-000 (lila) wherein L represents a linear partially or fully fluorinated alkylene group or an aliphatic hydrocarbon group, and R represents a linear partially or fully fluorinated aliphatic group or a linear partially or fully fluorinated aliphatic group interrupted with one or more oxygen atoms.

[0023] In one embodiment, the fluoroorganic anion is selected from formula (IlIb): G-Mf-Z (IlIb) wherein G and Z represent end groups and Mf represents at least one interpolymerized fluoroorganic monomer. The end groups are those known commonly in the art and comprise at least one ionic group, including, for example, a carboxylate, sulfonate, sulfinate, and combinations thereof. Exemplary fluoroorganic monomers include, for example, fluorinated olefins such as tetrafluoroethylene and hexafluoropropylene; vinyl fluoride; vinylidene fluoride; fluorinated alkoxy vinyl ethers; fluorinated alkyl vinyl ethers; hexafluoropropylene oxide, and combinations thereof. In one embodiment, M may additionally comprise interpolymerized non-fluorinated monomers, including, for example, olef ins such as ethylene or propylene.

[0024] Exemplary compounds comprising the fluoroorganic anions of formula Ill include: perfluorinated alkanoic acids and salts thereof, such as perfluoroacetic acid, perfluorobutanoic acid, perfluoropentanoic acid, perfluorohexanoic acid, perfluoroheptanoic acid, perfluorooctanoic acid, perfluorononanoic acid, perfluorodecanoic acid, perfluoroundecanoic acid, perfluorododecanoic acid, and perfluorotetradecanoic acid; partially fluorinated alkanoic acids and salts thereof, such as 6-fluorotetraacetic acid and 7H-perfluoroheptanoic acid; sulfonic acids and salts thereof such as: triflic acid, perfluorobutane sulfonic acid, perfluorohexane sulfonic acid, 1H,1H,2H,2H-tetrahydro perfluorooctane sulfonic acid and perfluorooctane sulphonic acid; sulfonamides such as perfluoromethanesulfonamide; and phosphonic acids and salts thereof such as perfluorohexylphosphonic acid, perfluorooctylphosphonic acid, and perfluorodecylphosphonic acid; and their salts and combinations thereof. Additional exemplary compounds comprising the fluoroorganic anions of formula Ill include: CF3CF200F2CF200F2000H, OH F2(0F2)5000H, 0F3(0F2)6000H, 0F30(0F2)300F(0F3)000H, OF3OF2OH200F2OH200F2000H, -.5 - [0025] CF3O(CF2)300H FCF2000H, CF3O(CF2)SOCF2000H, CF3(CF2)3(CH2CF2)2CF2CF2CF2000H, CF3(CF2)2CH2(CF2)2000H, CF3(CF2)2000H, CF3(CF2)2(OCF(CF3)CF2)OCF(CF3)COOH, CF3(CF2)2(OCF2CF2)400F(CF3)COOH, CF3CF2O(CF2CF2O)3CF2COOH, 2-perfluorohexyl ethanoic acid, 2-perfluoroctyl ethanoic acid, and 2-perfluorodecyl ethanoic acid, and their salts and combinations thereof.

[0026] In one embodiment, the fluoroorganic anion is selected from formula (IV): [R1-X1(O)N(R2) X2(O)-R31 (IV) wherein X1 and X2 may be the same or different and may be either C or S; R1, R2, and R3 may be the same or different; at least one of R1, R2, and R3 comprises a fluorine atom; and at least one of R1, R2, and R3 is a linear or branched, saturated or unsaturated carbon group, which may comprise other heteroatoms and/or functional groups, optionally, one or two of R1, R2, and R3 may be a H, F, CI, or Br. The number of carbons in R1, R2, and R3 can vary, including, for example carbon backbones comprising at least 1, 2, 3, 4, 6, 8, 10 or 12 carbon atoms or more. Exemplary fluoroorganic anions of formula IV include: (CF3SO2)2N.

[0027] In one embodiment, the fluoroorganic anion is a methide selected from formula (V): [R1R2R3C] (V) wherein R1, R2, and R3 may be the same or different and at least one of R1, R2, and R3 comprises a fluorine atom and at least one of R1, R2, and R3 is a linear or branched, saturated or unsaturated carbon group, which may comprise other heteroatoms and/or functional groups, optionally, one or two of R1, R2, and R3 may be a H, F, CI, ON, or Br.

The number of carbons in R1, R2, and R3 can varying, including, for example carbon backbones comprising at least 1, 2, 3, 4, 6, 8, 10, or 12 carbon atoms or more. In one embodiment, at least one of R1 or R2comprises a fluorinated sulfinate (i.e., RfSO2, where Rf is a fluorianted hydrocarbon).

[0028] In one embodiment, the fluoroorganic anion is an imide selected from formula (VI): [R1R2Nf (VI) wherein R1, and R2 may be the same or different and at least one of R1 and R2 comprises a fluorine atom and at least one of R1 and R2 is a linear or branched, saturated or unsaturated carbon group, which may comprise other heteroatoms and/or functional groups (such as for example sulfinates), optionally, one of R1 or R2 may be a H, F, Cl, ON, or Br. The number of carbons in R1 and R2 can vary, including, for example carbon backbones comprising at least 1, 2, 3, 4, 6, 8, 10, or 12 carbon atoms or more.

[0029] The fluoroorganic anion forms an ion pair with an organoammonium. The organoammonium of the present disclosure is organic and comprises a positively-charged nitrogen. The organoammonium of the present disclosure may be a protonated amine or a quaternary ammonium.

[0030] In one embodiment, the organoammonium compound is derived from an amine.

The amine may be a primary, secondary, or tertiary amine that comprises carbon chains, which are linear or branched, saturated or unsaturated, and optionally of varying lengths.

To obtain the organoammonium, the amine may be added to the process of the present disclosure as a salt or as the amine and protonated in situ by controlling the pH.

[0031] The amines of the present disclosure may be a liquid or a solid at room temperature. In one embodiment, the amine useful in the present disclose may be described as a water insoluble amine having a solubility in water of less than 1000 mg, 500 mg, 300mg, 100 mg, 50 mg, 20 mg, 10 mg, 5 mg, 3 mg, 2 mg, 1 mg, 0.75 mg, 0.5 mg, or even 0.25 mg per 1 00 mL when measured at ambient conditions.

[0032] In one embodiment, the organoammonium compound is derived from an amine of formula (I): NR1R2R3 (I) wherein R1, R2, and R3 may be the same or different and at least one of R1, R2, and ft3 is a linear or branched, saturated or unsaturated carbon group, which optionally may comprise heteroatoms (e.g., 0, N, S) and/or functional groups, including additional amine groups. Optionally, one or two of R1-R3 may be a H. The number of carbons in R1-R3 can vary, including, for example carbon backbones comprising at least 1, 2, 3, 4, 6, 8, 10, or 12 carbon atoms or more.

[0033] In one embodiment, the sum of R1, R2, and R3 in the amine comprises at least 5, 6, 7, 8, 10, 12, 14, 16, 20, or even 24 carbon atoms. Exemplary amines include: tributylamine, trioctylamine, tridecylamine, or tridodecylamine, including isomers and combinations thereof.

[0034] High purity tertiary amines are commercially available, for example, from Cognis, Monheim, Germany under the following trade designations: "ALAMINE 300" (tn-n-octylamine), "ALAMINE 308" (tri-isoctylamine), "ALAMINE 336" (tri(C8/C1o) amine), "ALAMINE 310" (tri-isodecylamine), and "ALAMINE 304" (tri-laurylamine).

[0035] In one embodiment, the organoammonium compound is derived form a quaternary ammonium salt. Unlike the amines disclosed above, which are protonated at a given pH, the quaternary ammonium generally is independent of the pH of the solution. In one embodiment, the quaternary ammonium salt is selected from formula (II): [NR1R2R3 R4]1M' (II) wherein R1, R, R3, and R4 may be the same or different and is a linear or branched, saturated or unsaturated carbon group, which optionally, may comprise other heteroatoms (e.g., 0, N, S) and/or functional groups, and M is an anion having a valence of i, wherein i is 1, 2, 3, or 4. The number of carbons in R1-R4 can vary, including, for example carbon backbones comprising at least 1, 2, 3, 4, 6, 8, 10, or 12 carbon atoms or more.

[0036] In one embodiment, the sum of R1, R2, R3, and R4 comprises at least 10, 16, 20, 24, 26, 28, 30, 34, 36, 38, or even 40 carbon atoms. Exemplary quaternary ammonium salts include those sold under the trade designations "ADOGEN 464" (methyltrialkyl(C8-C10)ammonium chloride) by Sigma-Aldrich and "ALIQUAT 336" (mixture of 08 (octyl) and (capryl) chains; and N-methyl-N,N-dioctyloctan-1-ammonium chloride) by Cognis Corp., Monheim, Germany.

[0037] In one embodiment two or more different organoammoniums may be used.

[0038] According to the present disclosure, the fluoroorganic anions are removed from an aqueous solution. The process may be applied to diverse aqueous solutions, comprising varying levels of fluoroorganic anions in a variety of matrices. Advantageously, diverse waste waters may be combined and treated according to the process of the present

disclosure.

[0039] The aqueous solution typically contains fluoroorganic anions at levels ranging from parts per billion (ppb) (e.g., ng/mL) to parts per million (ppm) (e.g., pg/mL). The aqueous solution may contain other components besides fluoroorganic anions (including organic solvents, salts, and/or other compounds), but will generally consist primarily of water. In other words at least 60, 75, 80, 85, 90, 95, or even 99% by weight of the aqueous solution is water.

[0040] In the present disclosure, an aqueous phase comprising the aqueous solution is contacted with the organoammonium. To assist the removal of the fluoroorganic anions from the aqueous phase, bulky organoammoniums may be used. If the sum of carbons is too low, the ion pair will be soluble in the aqueous phase and will not phase separate. The concentration of the organoammonium should be sufficient to ion pair with the fluoroorganic anion and enable extraction from the aqueous phase. Generally, the organoammonium to the fluoroorganic anion is in a ratio of at least 1:1, 1.1:1, 1.2:1, 1.5:1, 1.75:1, 2:1, 2.5:1, 5:1, 10:1, 25:1, 50:1, 100:1, 150:1, 200:1, 500:1, 750:1, 1000:1 based on moles of ion. Generally, a ratio of at least 150:1 may be used, since the higher the ratio of organoammonium to the fluoroorganic anion, the faster the reaction kinetics.

However, smaller or larger amounts can be used if desired.

[0041] Although not wanting to be bound by theory, it is believed that in one embodiment, the organoarnmonium pairs with a fluoroorganic anion to form a hydrophobic ion pair (or salt), which has a low melting point. Generally, a low melting point means a melting point of less than 100 C, 90 C, 80 C, 70 C, 60 C, 50 C, or even 40 20. The hydrophobicity and the low melting point will be determined based on the fluoroorganic anion and organoammonium pair. To achieve a hydrophobic ionic liquid, the fluoroorganic anion and organoammonium pair should have a water solubility of less than 5%, 4%, 3%, 2%, 1%, 0.5%, 0.1%, 0.05% or even 0.01% by weight based on ambient conditions. Because the hydrophobic salt has a low melting point, it will be liquid; and because the salt is hydrophobic, the hydrophobic ionic liquid may separate from the aqueous phase forming a bi-phasic solution. Optionally, a solvent may be used to extract the hydrophobic liquid into an organic phase (i.e., a non-aqueous phase).

[0042] Modifiers may be present in the process of the present disclosure, which can modify or improve the ion pairing, phase separation, and/or other important characteristics of the process. These modifiers include, for example, organic solvents or salts.

[0043] In one embodiment, an organic solvent is present in the process. As used herein, an organic solvent is a solvent not comprising organoammonium, or precursors thereof.

The organic solvent may be present in the aqueous solution or may be added to the aqueous phase or the non-aqueous phase. The organic solvent may be present in the sample matrix.

[0044] In one embodiment, an organic solvent is added to the process. The solvent may be added to dissolve an amine that is a solid at room temperature, or to assist in extracting the hydrophobic ionic pair from the aqueous phase. For example, non-fluorinated organic solvents, such as ethyl acetate and methyl ethyl ketone, are known to extract fluoroorganic anions from aqueous solutions via a liquid-liquid extraction process.

However, because liquid-liquid extraction of fluoroorganic anions with an organic solvent is based on the fluoroorganic anion partitioning between the two phases, the organic solvents may be difficult and expensive to re-cycle and are generally not amenable to treatment with commonly employed water treatment methods (e.g., biological oxidation/reduction, physical separation, etc.). Advantageously, in one embodiment of the present disclosure, the use of the organoammonium (e.g., an organoammonium derived from an amine) may be used to extract the fluoroorganic anions from an aqueous phase and the organoammonium may be regenerated with an aqueous basic solution as will be described below.

[0045] In the present disclosure, it is believed that a hydrophobic ion pair is formed. An organic solvent may be is used to enhance the removal of the hydrophobic ionic pair from the aqueous phase into a non-aqueous (organic) phase. Because the fluoroorganic anion exists as an ion pair in the organic solvent, the non-aqueous phase may be subsequently -.9-processed to remove and optionally concentrate the fluoroorganic anions, as will be described below.

[0046] These organic solvents are substantially water immiscible aliphatic and aromatic hydrocarbons. Aliphatic hydrocarbons such as alkanes, including cycloalkanes and halogenated alkanes are suitable. Preferred alkanes have a minimum of five carbon atoms. Preferred halogenated alkanes have a minimum of two carbon atoms. Aromatic hydrocarbons which can be used include benzene, and substituted products such as toluenes, xylenes, and cumene. Also suitable as solvents are those esters, ethers, ketones, and alcohols which are substantially water immiscible. Furthermore, any blend of these substances or a water-immiscible kerosene is also suitable. Exemplary organic solvents include: ethyl acetate, methyl ethyl ketone, heptane, hexane, and combinations thereof.

[0047] In one embodiment, the extraction process comprises less than 100, 200, 400, or even 500 ppm of organic solvent and/or more than 50, 20, 10, 5, 1, 0.5, 0.1, or even 0.05 ppm of organic solvent.

[0048] In one embodiment, the organic phase is substantially free of a solvent, meaning there is less than 0.01 ppm organic solvent present.

[0049] Traditionally, in removal techniques such as ion exchange resins, high salt in the aqueous solution may cause problems with ion exchange, however, in the present disclosure, the water soluble salt may assist in the removal of fluoroorganic anions from aqueous solutions. In one embodiment, the aqueous phase comprises a water soluble salt in amounts of at least 0.1%, 0.2%, 0.4%, 0.6%, 1%, 2%, 5%, 10%, or even 15% by weight based on the total weight of the aqueous phase; at most 30%, 40%, 50%, 60%, or even 70% by weight based on the total weight of the aqueous phase.

[0050] Depending on the source of the aqueous solution and its components, the pH of the aqueous phase may need to be adjusted to deprotonate the fluoroorganic anions and/or protonate at least some of the amine to enable ion pairing. Therefore, in one embodiment, the pH of the aqueous phase could have a pH within the range of less than 9, 7, 6.8, 6.5, 6, 5.5, or even 5 and more than 0, 1, 2, 3, or even 4. In one embodiment the pH of the aqueous phase is between 4 to 6.8. Acids or bases may be added to the aqueous phase to control the pH, if necessary. Exemplary acids for pH control include: hydrochloric, hydrofluoric, nitric, sulfuric, hydrobromic, and phosphoric. Exemplary bases for pH control include: alkali metal or alkaline earth metal bases, particularly potassium hydroxide, sodium hydroxide, ammonium hydroxide and sodium carbonate. -10-

[0051] In one embodiment, carbon dioxide may be introduced in the process to adjust the pH. The carbon dioxide may be added as a solid or a bubbled through the liquid in a gas form.

[0052] After the aqueous phase and organoammonium are contacted they form a mixture, which is agitated. The organoammonium should contact the aqueous phase for a sufficient length of time to permit contact of the fluoroorganic anion with the organoammonium. The time of contact depends on the particular system, the volume of the reaction mixture, the type of equipment used, and upon individual needs and desires.

As a general rule, however, the contact time between the organoammonium and the aqueous phase should be in excess of 0.1 seconds with some equipment, but generally less than 5, 4, 3, or even 2 hours. Exemplary equipment that may be used for agitation include: vortexers, agitators, sonicators, and other such equipment as known in the art.

[0053] In the process of the present disclosure, the respective concentrations of the non-aqueous phase (comprising the organoammonium) and aqueous phase can vary widely depending on individual circumstances and needs. The process may be conducted in a continuous process (e.g. a twin counter-current system, one for extraction of fluorochemicals from the waste stream and the other for rejuvenation/recycling of the extractant) or a batch process.

[0054] The temperature of the mixture during agitation may be controlled to enhance the removal. In one embodiment, a temperature of less than 8OC, 6OC, 4OC, 35C, 3OC, 25C, 2OC, or less than l5C may be used so long as the non-aqueous phase, including the hydrophobic salt is still a liquid.

[0055] Because of immiscibility, the aqueous phase and non-aqueous phase generally separate after agitation has stopped. In one embodiment, the mixture, although bi-phasic, does not phase separate on its own. Therefore, measures as known in the art, may be used to promote the phase separation, including centrifugation.

[0056] After agitation and phase separation, the extracted fluoroorganic anions are ideally contained in the non-aqueous phase. In one embodiment, the extracted aqueous phase is substantially free of fluoroorganic anions (i.e., less than 0.1 ppb). In another embodiment, the extracted aqueous phase comprises less than 5%, 2%, 1%, 0.5%, 0.1%, 0.05%, 0.01%, 0.005%, or even 0.0001% by weight of fluoroorganic anions. In one embodiment, the extracted aqueous phase may be reprocessed repeatedly according to the present disclosure if the extracted aqueous phase still contains a non-desirable amount of fluoroorganic anions. Alternately, or additional, process parameters may be adjusted to enhance the efficiency of a single extraction.

[0057] After sufficiently removing the fluoroorganic anions from the aqueous solution, the extracted aqueous phase can then be subsequently treated with commonly employed waste water treatment schemes (or other low energy/low cost approaches) or possibly discharged to the environment directly.

[0058] The density of the non-aqueous phase and the aqueous phase will determine which phase is the top and bottom phase following phase separation. In one embodiment, the aqueous phase has a density higher than the non-aqueous phase and thus, is the bottom portion of the phase separation. In this embodiment, a valve at the bottom of the extraction vessel may be opened to drain the aqueous phase out of the vessel.

[0059] In some embodiments, the processes of the present disclosure will remove the fluoroorganic anion from the aqueous solutions at concentrations of less than about 1 ppb. It will be appreciated that exact limits will vary depending on the specific chemical identity of the fluoroorganic anion as well as the measurement equipment being used.

[0060] The present disclosure can be used to remove fluoroorganic anions from aqueous solutions having fluoroorganic anion concentrations as low as 0.2 ppb, 0.4 ppb, 0.5 ppb, 0.75 ppb, 1 ppb, 2 ppb, 5 ppb, 10 ppb, 100 ppb, 200 ppb, 500 ppb, 750 ppb, 1 ppm, 5 ppm, 10 ppm, 100 ppm, or even as low as 500 ppm; and greater 1000 ppm, 5000 ppm, 10,000 ppm, 15,000 ppm, 20,000 ppm, 50,000 ppm, or even greater than 100,000 ppm.

[0061] After applying the process as disclosed herein to an aqueous phase (e.g., a waste stream), the resulting aqueous phase will typically comprise less than 10000 ppm (1% by weight), 100 ppm, lppm, lOOppb, 10 ppb, 1 ppb, or even 0.1 ppb of fluoroorganic anions.

In one embodiment, the process according to the present disclosure is able to remove 70%, 80%, 90%, 95%, 98%, 99% or even 100 % of the fluorooragnic anions from the aqueous phase (e.g., waste stream) using just one iteration of the process according to the present disclosure. With fluoroorganic anions that are not easily removed (or extracted) from the aqueous phase (i.e., less than 50% removal), the process according to the present disclosure may need to be repeated at least 2 or more times.

[0062] The non-aqueous phase comprising the hydrophobic salt, may be subsequently washed with an aqueous alkaline solution, allowing the ability to concentrate the fluoroorganic anions and regenerate the organoammonium. In one embodiment, a base may be added to the non-aqueous phase to recover the fluoroorganic anion, and optionally, to regenerate the organoammonium. Suitable bases include those that are able to displace the organoammonium (i.e., those that are more basic than the organoammonium). Exemplary bases include, the alkali metal or alkaline earth metal bases, including for example, potassium hydroxide, sodium hydroxide, and ammonium hydroxide. -12-

[0063] After contacting the aqueous base with the non-aqueous phase, the fluoroorganic anions may be transferred into the aqueous base phase. The non-aqueous phase containing the organoammonium freed from the fluoroorganic anion may be recycled, i.e., reused for treatment of aqueous solutions containing fluoroorganic anions (e.g., industrial waste streams or ground water). The fluoroorganic anions removed with the aqueous base can be recovered by techniques as is known in the art. See, for example, U.S. Pat. Nos. 5,312,935 (Mayer et al.) and 7,126,016 (Fu et al.) and U.S. Publ. No. 2005-0177000 (Fuehrer et al.). The recovered fluoroorganic anions will typically have a purity sufficient to allow use of the fluoroorganic anion in subsequent synthesis (for example, emulsion polymerization of fluoroorganic monomers).

[0064] Advantageously, the process of the present disclosure may be used to extract fluoroorganic anions from a variety of matrices. Further the process of the present disclosure may require smaller volumes of extractant (organoammonium) to remove the fluoroorganic anions from the aqueous phase than in traditional removal processes, resulting in a more effective, lower cost process.

EXAMPLES

[0065] Advantages and embodiments of this disclosure are further illustrated by the following examples, but the particular materials and amounts thereof recited in these examples, as well as other conditions and details, should not be construed to unduly limit this invention. In these examples, all percentages, proportions and ratios are by weight unless otherwise indicated. If not otherwise indicated all materials were obtained from Aldrich Chemical, Milwaukee, WI.

[0066] These following abbreviations are used in the examples: g = grams, mm minutes, hr = hour, mL = milliliter, L = liter.

Table 1 Materials

TOA Trioctylamine, ccommercially available from Aldrich _______________________________ Chemical, Milwaukee, WI Ethyl acetate Commercially available from Aldrich Chemical, _______________________________ Milwaukee, WI MEK Methyl ethyl ketone, commercially available from __________________________________ Aldrich Chemical, Milwaukee, WI ALAMINE 304-1 Tridodecyl amine available commercially from __________________________________ Cognis, Monheim, Germany.

ALAMINE 308 Triisooctyl amine available commercially from __________________________________ Cognis, Monheim, Germany.

ALAMINE 336 Tn octyl-decyl alkylamine available commercially from Cognis, Monheim, Germany.

-13 -MDOA N-methyl-dioctylamine commercially available from ________________________________ TCI America, Portland, OR DMDOA N, N-dimethyloctylamine commercially available from Avocado Research Chemicals Ltd., Lancashire, UK (now part of Alfa Aesar, Ward Hill, ________________________ MA) TBA Tributylamine, commercially available from Aldrich _______________________________ Chemical, Milwaukee, WI THA Trihexylamine, commercially available from Alfa ________________________________ Aesar, Heysham, Lancs. UK OA Octylamine, commercially available from Alfa ________________________________ Aesar, Heysham, Lancs. UK DOA Dioctylamine, commercially available from Alfa ________________________________ Aesar, Heysham, Lancs. UK ADOGEN Methyltrialkyl(C8-C1 0)ammonium chloride commercially available from Aldrich Chemical, Milwaukee, WI under the trade designation ______________________________ "ADOGEN 464" CF300F2CF2CF2-O-CFHCF2002NH4 Ether acid salt prepared as described in U.S. Pat. ________________________________ No 7,671,1 12 (Hintzer et al.) as Compound 11.

PFAA CF3000H obtained from Baxter Healthcare Corp., __________________________________ Muskegon, MI PFPA CF3CF2000H obtained from Matrix Scientific, _______________________________ Columbia, SC.

PFBA CF3CF2CF2000H obtained from Synquest __________________________________ Laboratories Inc. Alachua, FL.

Lithium triflate CF3SO3Li obtained from 3M Co., St. Paul, MN.

PBSK CF3CF2CF2CF2SO3K obtained from 3M Co., St. _____________________________ Paul, MN.

(CF3502)2NLi Lithium salt of of (trifluoromethylsulphonyl) imide ________________________________ obtained from 3M Co., St. Paul, MN [0067] Aqueous Solution A was made by spiking distilled water with 5 fluoroorganic acids resulting in a final concentration of: 100 ppb perfluorooctanoic acid (PFOA), 100 ppb perfluorooctane sulfonic acid (PFOS), 100 ppb perfluorohexanoic acid (PFHxA), 100 ppb perfluorononanoic acid (PFNA) and 100 ppb perfluorodecanoic acid (PFDA). These acids are available commercially as standards from Wellington Laboratories, Guelph, Ontario.

The spiking amounts were determined by appropriate dilutions of the standards and were not analyzed by F19-NMR. The pH of this solution was between about 6.0 and 6.5.

[0068] Aqueous Solution B was made by spiking distilled water with the following 7 fluoroorganic acids or their salts: CF300F2CF2CF200FHCF2002NH4, PFAA, PFPA, PFBA, lithium triflate, PBSK, and (CF3502)2NLi. This resulted in a spiked solution with a final concentration of: 0.00640 % by weight (CF300F2CF2CF2OFCHCF2002NH4); 0.00558 % (PFAA); 0.00467 % PFPA; 0.0106 % PFBA; 0.00665 % triflic acid, CF3SO3H; 0.01 47 % PBSK; and 0.0107 % ((CF3SO2)2NH). The spiking amounts were determined -14-by appropriate dilutions of standards and were not analyzed by F19-NMR. The pH of this solution was 3.2.

[0069] Examples 1-4: In these examples, 5 g of Aqueous Solution A was used. The pH of the Examples 2 and 4 was adjusted using dry-ice powder, resulting in a pH of 4. TOA was added to the aqueous solution as indicated in Table 2. The mixtures were vigorously vortexed at maximum speed (VWR Mini Vortexer) in polypropylene centrifuge tubes for 5 minutes. The mixture was set aside for 5 minutes to allow a phase separation. The water phase then was analyzed for the fluoroorganic acids by LC-MS (liquid chromatography-mass spectroscopy) and the results are shown in Table 2.

Table 2

Example Amount TOA Amount % Extracted Added Dry-ice _________ ________ _________ __________ ________ Added PFOA1 PFOS1 PFHxA PFNA2 PFDA2 1 1 mL 0 >99 >99 92.1 >99.5 >99.5 2 lmL 1 g >99 >99 99.1 >99.5 99 3 0.1 mL 0 >99 >99 44.0 >99.5 >99.5 4 0.1 mL 1 g >99 96.5 97.9 98.6 89.2 1: no residual detectable (detectable limit estimated at 1 ppm) 2: no residual detectable (detectable limit estimated at 0.5 ppm) [0070] Examples 5-20: The effect of amine type and amount and salt type and amount on the recovery of fluoroorganic anions in aqueous solutions was investigated in Examples 5-20 (Ex 5-20). In these examples, 5 g of Aqueous Solution B was used. The pH of the samples was adjusted with 0.1 mL HCI. A water insoluble amine was added to the aqueous solution along with, in some instances salt as indicated in Table 3 to form a mixture. The mixture was vigorously vortexed at maximum speed (VWR Mini Votexer) in a polypropylene centrifuge tube for 5 minutes. The mixture was set aside for 5 minutes to allow the water insoluble amine to separate from the water (i.e., a phase separation). The original Solution B and the bottom phases (water phases) were analyzed for the fluorinated acid by F19-NMR and the % extracted in each case is shown in Table 3. The results show that for some acids, such as (CF3SO2)2NH and CF300F2CF2CF200FHCF2CO2NH4, the amine type and amount and salt type and amount do not substantially effect extraction efficiency. For harder to extract fluoroorganic anions such as PFAA, the % extracted was impacted by the type and amount of water insoluble amine used, and the type of salt used (inorganic versus organic salts).

Table 3

Ex Amine Amine tL Mole ratio Salt (g added) % Extracted Q.teq) amuie: total CF3OCF2CF2CF2O PFAA PFPA PFBA Lithium PBSK (CF3SO2)2N _____ _________ __________ ___________ _____________ CFHCF2CO2NH4 _______ ______ ______ tnt late _______ Li TOA 7.9(18) 1 None 100 23 62 93 88 100 100 6 TOA 15.8(36) 2 None 100 61 91 100 100 100 100 7 TOA 39.4 (90) 5 None 100 84 99 100 100 100 100 8 TOA 394 (901) 54 NaCI (0.25) 100 96 100 100 100 100 100 9 TOA 394 (901) 54 NaCI(1.5) 100 95 100 100 100 100 100 TOA 394 (901) 54 CH3SO4K(1.6) 100 55 89 100 92 100 100 _____ _________ __________ ___________ KF(0.6) ________________ _______ ______ ______ _______ _______ ___________ 11 TOA 88.6(203) 12 CH3SO4K(1.6) 100 86 99 100 98 100 100 _____ _________ __________ __________ KF(0.6) _______________ _______ ______ ______ _______ ______ __________ 12 TBA 47 (199) 12 NaCI (0.50) 100 12 14 27 13 100 100 13 TBA 545 (901) 54 NaCI (0.50) 100 16 14 35 19 93 100 14 THA 67 (199) 12 NaCI (0.50) 100 80 96 100 100 100 100 THA 776(901) 54 NaCI (0.50) 100 93 100 100 100 100 100 16 OA 15(90) 5.4 NaCI (0.50) 100 12 16 15 17 32 33 17 DOA 27 (90) 5.4 NaCI (0.50) 100 34 51 75 16 90 100 18 DOA 272 (901) 54 NaCI (0.50) 100 52 83 92 19 100 100 19 MDOA 29(90) 5.4 NaCI (0.5) 100 9 12 16 11 71 98 DMDOA 18 (90) 5.4 NaCI (0.5) 72 12 8 11 14 30 93 -16 - [0070] Foreseeable modifications and alterations of this invention will be apparent to those skilled in the art without departing from the scope and spirit of this invention. This invention should not be restricted to the embodiments that are set forth in this application for illustrative purposes.

Claims

Claims: 1. A process for removing fluoroorganic anions from an aqueous phase, the process comprising: contacting the aqueous phase with a organoammonium, wherein a fluoroorganic anion from the aqueous phase and the organoammonium form a hydrophobic ion pair; and then separating the hydrophobic ion pair from the aqueous phase, wherein the resulting aqueous phase comprises less than 1 % by weight of the fluoroorganic anions.
2. The process according to claim 1, further comprising a water soluble salt, wherein the water soluble salt is present when the hydrophobic ion pair is separated from the aqueous phase.
3. The process according to claim 2, wherein the aqueous phase further comprises 0.2% to 50% by weight of the water soluble salt based on the total weight of the aqueous phase.
4. The process according to any one of the previous claims, wherein the resulting aqueous phase has a pH greater than 4.
5. The process according to any one of the previous claims, wherein the resulting aqueous phase has a pH less than 9.
6. The process according to any one of the previous claims, wherein the aqueous phase comprises 0.4 ppb to 50,000 ppm of the fluoroorganic anions.
7. The process according to any one of the previous claims, wherein the process is conducted at a temperature of less than 80 C.
8. The process according to any one of the previous claims, wherein the hydrophobic ion pair is separated from the aqueous phase via a phase separation.
9. The process according to any one of the previous claims, wherein the process is substantially free of a solvent.-17 -
10. The process according to any one claims 1-7, wherein the hydrophobic ion pair is separated from the aqueous phase via a liquid-liquid extraction.
11. The process according to any one claims 1-8 or 10, further comprising adding a solvent.
12. The process according to claim 11, wherein the solvent is at least one of ethyl acetate, methyl ethyl ketorie, heptane, hexane, and combinations thereof.
13. The process according to any one of the previous claims, wherein the fluoroorganic anion is at least one of a carboxylate, a sulfonate, a sulfonamide, a phosphonate, an imide, a methide, an anion of telomer acids, and combinations thereof.
14. The process according to any one of the previous claims, wherein the organoammonium is derived from at least one of: (i) an amine of formula (I): NR1R2R3 (I) wherein R1, R2, and R3 may be the same or different and at least one of R1, R2, and 1R3 is a linear or branched, saturated or unsaturated carbon group, which optionally, may comprise heteroatoms, and optionally, wherein one or two of R1-R3 may be a H; and (ii) a quaternary ammonium salt of formula (II): [NR1R2R3 R4]1A' (II) wherein R1, R2, R3, and R4 may be the same or different and comprise a linear or branched, saturated or unsaturated carbon group, which optionally, may comprise other heteroatoms and/or functional groups, and A is an anion having a valence of i, wherein i is 1, 2, 3, or 4.
15. The process according to claim 14, wherein the amine is at least one of: trihexylamine, trioctylamine, tridecylamine, tridodecylamine, and combinations thereof, and the quaternary ammonium salt is at least one of: methyltrialkyl(C8-C10)ammonium salt, N-methyl-N,N-dioctyloctan-1 -ammonium salt, and combinations thereof.
16. The process according to any one of the previous claims, wherein the mole ratio of the organoammonium ion to the fluoroorganic anion is at least 1.1 to 1.
17. The process according to any one of the previous claims, wherein the aqueous phase is contacted with carbon dioxide to adjust the pH to less then 9.-18 -
18. The process according to any one of claims 1-16, wherein the aqueous phase is contacted with hydrochloric acid or sulfuric acid to adjust the pH to less then 9.
19. The process according to claim 1, further comprising adding a base to the hydrophobic ion pair to recover the fluoroorganic anions.
20. The process according to any one of the previous claims, further comprising adding a base to the hydrophobic ion pair to regenerate the organoammonium.22. The process according to any one of claims 19-20, wherein the base is at least one of: KOH, NH4OH, NaOH, and combinations thereof.23. A process for removing fluoroorganic anions from an aqueous phase comprising contacting the aqueous phase with an organic phase comprising at least one water insoluble amine to form a mixture; agitating the mixture to extract the fluoroorganic anions into the organic phase; allowing the mixture to phase separate; separating the organic phase from the aqueous phase; and optionally, adding a base to the organic phase to recover the fluoroorganic anions, and/or to regenerate the water insoluble amine.-19 -