Gels as size selective extraction solvents



We have successfully used cross-linked, partially-hydrolyzed, polyacrylamide gels to concentrate solutions of high molecular weight solutes. The gels are sizeselective, concentrating solutes whose diameter exceeds 3 nm. They can be easily regenerated by means of pH-induced changes in gel swelling; this regeneration is consistent with that inferred from existing theories of gel swelling. The resulting separation process is a good alternative to ultrafiltration.