Synthesis of novel chelating resins containing dithiophosphoric functionality and comparison to analogous solvent impregnated resins

Functional polymers (III-VIII) incorporating thiophosphoric acids were synthesized. Analogous solvent impregnated resins (SIRs) were made from polyvinyl pyridine and polyvinyl benzyl ammonium types of ionic polymers by impregnation of di(2-ethylhexyl)-dithiophosphoric acid. The polymers and their metal complexes were characterized by FTIR. Surface area measurements of the SIR-type polymer reveal surface area and pore volume reduction upon metal ion complexation. Both covalent and impregnated-type polymers show selectivity towards Cu, Cd, Ni, and Pb. Solvent impregnated resins are more effective and more selective than the covalent type of resins. Column experiments allowed collection of toxic metals from sub-ppm concentrations and clear separation between favored metal ions and other ions.