Synthesis, characterization and mechanistic studies on the ion-exchange/precipitation class III dual mechanism bifunctional polymers

Bifunctional polymer-supported reagents containing phosphonic acid groups and quaternary amine groups were synthesized via a two-step functionalization using new approaches. The bifunctionalities of the resins were investigated by IR and solid state NMR analyses. Kinetic studies on the extraction of silver ion using chloride-form bifunctional resins and thiocyanate-form bifunctional resins and the extraction of lead ion using iodate-form resins were conducted. The results show that the ion extraction kinetics depend on a resin's quantitative properties (including bifunctional compositions, the crosslinking level of the resin, the bead size) and on a resin's qualitative properties (including the macroporosity of the resin, the properties of the amine-associated anions, the bifunctionalities of the resin, and the bifunctionalization history of the resins) Both positive and negative bifunctionally synergistic effects on the ion extractions were observed, depending on different quantities and qualities of the resins. It was found that the bifunctionalization of a polymer support with the same functional group ratio might result in bifunctional resins with different behavior because of the polyconfiguration of these resins. It is suggested that multiplicities of the structure of bifunctional resins give different kinetics of ion extraction via different mechanisms.