Patent ID: 8382989

Claim:
A process for separating a charged species from an aqueous system, wherein the process comprises the following steps: (a) contacting a first aqueous system comprising the charged species at a first temperature with an ampholytic polymeric system comprising cationic and anionic groups, wherein the charged species is bonded to the ampholytic polymeric system; and (b) contacting the ampholytic polymeric system with a second aqueous system at a second temperature less than 60° C., wherein the charged species is released to the second aqueous system, and wherein the second temperature is higher than the first temperature; and wherein the ampholytic polymeric system is an interpenetrating network or a semi-interpenetrating network; the interpenetrating network or the semi-interpenetrating network comprising a cationic monomer and an anionic monomer, wherein the molar ratio of cationic monomers to anionic monomers is in the range of 5:1 to 1:5, wherein the cationic monomer has the formula: CH 2 ═C(R)—R′—NR 1 R 2 .R*X wherein: R is selected from the group consisting of H and CH 3 ; R′ is absent, or an optionally functionalised spacer; R 1 and R 2 are independently selected from the group consisting of H, CH 2 linear or branched alkyl and C 6-12 aryl; X is halogen or ½ SO 4 ; and R* is H, CH 1-2 linear or branched alkyl, or C 6-12 aryl, or a polymer or copolymer thereof; or wherein the cationic monomer has the formula: CH 2 ═CRC(O)NH—R 3 —NR 1 R 2 .R*X wherein R is selected from the group consisting of H and CH 3 , R 1 and R 2 are independently selected from the group consisting of H, CH 2 linear or branched alkyl and C 6-12 aryl, R* is H, C 1-12 linear or branched alkyl, or C 6-12 aryl, R 3 is C 1-12 linear or branched alkyl, and X is halogen or ½ SO 4 , and wherein the interpenetrating network or the semi-interpenetrating network comprises a lower critical solution temperature (LCST) monomer.