STUDIES ON SELECTIVE ADSORPTION RESINS .3 5. CHELATING RESINS CONTAINING SULFUR DONORS DERIVED FROM MACRORETICULAR GLYCIDYL METHACRYLATE-DIVINYLBENZENE COPOLYMER BEADS AND THEIR BEHAVIOR IN ADSORPTION AND ELUTION OF AU(III), PD(II) AND PT(IV)

In order to develop chelating resins having high adsorption and elutio n abilities toward noble metal ions, resins containing epithio groups (RGS) were prepared by the reaction of macroreticular glycidyl methacr ylate-divinylbenzene copolymer beads (RG) with saturated methanol solu tion of ammonium thiocyanate. Alternative resins having mercapto group s (RGSH) were also derived from RGS by treatment with ethanolic potass ium hydrogensulfide. From a series of RGs prepared by systematically c hanging amounts of the diluent 4-methyl-2-pentanone, and the crosslink ing agent, divinylbenzene, in suspension polymerization, RGSs and RGSH s with different specific surface areas and degrees of crosslinking we re derived, and their behavior in adsorption and desorption of Au (III ), Pd (II) and Pt (IV) was studied. The RGS10-160 and RGSH10-160, whic h were derived from the RG prepared by using 10 mol% of divinylbenzene and 160 vol% of the diluent, exhibited the highest capacities for upt ake of each metal ion, respectively. Bachwise elution study has clarif ied that the metal ions adsorbed on RGS10-160 or RGSH10-160 are effect ively eluted with 0.1-0.2 mol . dm-3 aqueous potassium cyanide; in par ticular, the elution of Au(III) and Pd(II) adsorbed on RGS10-160 is ea sy. The column-mode study on RGS10-160 has also revealed that each met al ion can be quantitatively eluted with 0.2 mol . dm-3 potassium cyan ide. Although the separation of Au(III) and Pd(II) with cyanide eluent s was difficult, the quantitative separation of Au(III) and Pt(IV) was successfully achieved by changing the concentration of cyanide eluent s.