Perchlorate removal using ion exchange resins comprising interpenetrating polymer networks
View Patent ↗The invention includes ion exchange resins, methods of making ion exchange resins and their use in the removal of perchlorate from water. In one embodiment, the invention comprises a method for removing perchlorate from a water source by contacting the water with an ion exchange resin, wherein the ion exchange resin comprises particles of a crosslinked copolymer comprising: an interpenetrating polymer network (IPN) of at least two polymer components each having a styrenic content greater than 50 molar percent, and a quaternary ammonium functionality.
1. A method for removing perchlorate from a water source by contacting the water with an ion exchange resin, wherein the ion exchange resin comprises particles of a crosslinked copolymer comprising: an interpenetrating polymer network (IPN) of at least two polymer components each having a styrenic content greater than 50 molar percent, and a quaternary ammonium functionality.
2. The method of claim 1 wherein the crosslinked copolymer has a styrenic content of greater than 75 molar percent.
3. The method of claim 1 wherein the quaternary ammonium functionality comprises a nitrogen atom bonded to a benzyl carbon of the copolymer and three alkyl groups, wherein each alkyl group may be substituted or unsubstituted.
4. The method of claim 1 wherein the quaternary ammonium functionality comprises a nitrogen atom bonded to a benzyl carbon of the copolymer and three alkyl groups, wherein each alkyl group independently comprises from 2 to 6 carbon atoms.
5. The method of claim 1 wherein the quaternary ammonium functionality comprises a nitrogen atom bonded to a benzyl carbon of the copolymer and three alkyl groups, wherein the alkyl groups are collectively selected from: triethyl, tripropyl, tributyl, tripentyl, trihexyl, and dimethylisopropyl.
6. The method of claim 1 wherein the quaternary ammonium functionality comprises a nitrogen atom bonded to a benzyl carbon of the copolymer and three n-butyl groups.
7. The method of claim 1 wherein the crosslinked copolymer comprises a gel-type copolymer.
8. The method of claim 1 wherein the copolymer includes a repeating unit represented the following formula:
wherein the benzyl carbon is located at the meta, ortho or para position of the aromatic ring; and R 1 , R 2 and R 3 are each independently selected from alkyl groups comprising from 2 to 6 carbon atoms.