High stability solvent impregnated resins: Metal ion complexation as a function of time

Solvent impregnated resin (SIR) beads with bis(2-ethylhexyl)hydrogen phosphate (DEHPA) as the complexant have been coated with a semipermeable membrane consisting of poly(glycidyl methacrylate-co-N,N'-methylene-bis(acrylamide)). The coated SIR beads have been studied through six contact/regeneration cycles with no loss of complexing ability, in contrast to the behavior of uncoated SIR beads. The semipermeable membrane does not hinder the complexation of Cu(II) ions: results with the coated SIR beads are identical at 15 min and 24 hr contact times.