APPLICATION OF CHELATE FORMING RESIN AMBERLITE XAD-2-O-VANILLINTHIOSEMICARBAZONE TO THE SEPARATION AND PRECONCENTRATION OF COPPER(II), ZINC(II) AND LEAD(II)

A very stable chelating resin matrix was synthesized by covalently lin king o-vanillinthiosemicarbazone (oVTSC) with the benzene ring of the polystyrene-divinylbenzene resin Amberlite XAD-2 through a -N double b ond N- group. The resin was used successfully for the separation and p reconcentration of copper(II), zinc(II) and lead(II) prior to their de termination by atomic absorption spectrophotometry. The total sorption capacity of the resin was 850, 1500 and 2000 mu g g-l of the resin fo r Cu(II), Zn(II) and Pb(II), respectively. For the quantitative sorpti on and recovery of Cu(II), Zn(II) and Pb(II), the optimum pH and eluan ts were pH 2.5-4.0 and 4 M HCl or 2 M HNO3 for Cu(II), pH 5.5-6.5 and 1.0-2.0 M HCl for Zn(II) and pH 6.0-7.5 and 3 M HC or 1 M HNO, for Pb( II). Both, the uptake and stripping of these metal ions were fairly ra pid, indicating a better accessibility of the chelating sites. The t(1 /2) values for Cu(II), Zn(II) and Pb(II) were also determined. Limit o f toleranc of some electrolytes like NaCl, NaF: NaNO3, Na2SO4 and Na3P O4 have been reported. The preconcentration factor for Cu(II), Zn(II) and Pb(II) was 90, 140 and 100 respectively. The method was applied fo r the determination of Cu(II), Zn(II) and Pb(II) in the water samples collected from Sabarmati river, Ahmedabad, India. (C) 1997 Elsevier Sc ience B.V.