ENHANCED COPPER SELECTIVITY AND FASTER SORPTION KINETICS OF POLY(4-VINYLPYRIDINE) CROSS-LINKED IN PRESENCE OF COPPER(II) AS TEMPLATE ON SILICA-GEL

Poly(4-vinylpyridine) supported on silica gel using Cu(II) as template ion has been crosslinked by quaternization with 1,4-dibromobutane to obtain a selective sorbent, SiO2..[PVP.TQ(Cu)], which shows significantly greater selectivity than unquaternized and unsupported resin, PVP, for copper sorption in the presence of nickel. SiO2..[PVP.TQ(Cu)] has a 5-fold greater saturation capacity (per unit mass of resin) and a 220-fold larger binding constant for Cu(II) sorption, as compared to PVP. There is also an order of magnitude increase in the rate of sorption, the t1/2 values for the sorption being 8 and 102 min with effective diffusivities of Cu(II) 1.7 x 10(-6) and 2.7 x 10(-7) cm2/s in SiO2..[PVP.TQ(Cu)] and PVP, respectively. While the loaded Cu(II) is stripped easily by HCl on both SiO2..[PVP.TQ(Cu)] and PVP, the former has an order of magnitude higher rate of stripping than the latter for the same strength of the stripping agent.