BEHAVIOR OF MERCAPTO GROUP BASED CHELATING RESINS DERIVED FROM MACRORETICULAR 2,3-EPITHIOPROPYL METHACRYLATE-DIVINYLBENZENE COPOLYMER BEADSIN ADSORPTION AND ELUTION OF SEVERAL NOBLE-METALS

Chelating resins containing mercapto groups (RES) were developed by th e functionalization of macroreticular 2,3-epithiopropyl methacrylate-d ivinylbenzene copolymer beads (RE) with alcoholic potassium hydrogensu lfide. The resins RES with different pore structures were derived from a series of RE prepared by changing the compositions of ternary mixtu res consisting of the two monomers and 2-ethylhexyl alcohol as diluent (porogen) in suspension copolymerization. Behavior of RES in adsorpti on and elution of noble metals was studied. The uptake of these metals is strongly influenced by crosslinking densities and specific surface areas (pore structures) of RES. The RES with the highest capacities f or the metals can be derived from the highly porous RE prepared by usi ng 10 mol% of divinylbenzene and 100 vol% of the diluent per the monom eric mixture. The increasing order in the metal uptake by the RES is a s follows: Pt(IV) approximately Ir(IV) much less than Pd (II) < Os (VI II) much less than Au(III). The adsorbed Au (III), Pd (II) and Pt (IV) on the RES were effectively and rapidly eluted with 0.1-0.2 mol . dm- 3 aqueous potassium cyanide solutions, whereas the elution of the adso rbed Os(VIII) and Ir(IV) with the eluents was extremely difficult to a chieve.