Studies on polyvalent metal ion bound guargum-graft-acrylamide

Abstract

Guargum-graft-acrylamide (G-g-Am) is a modified natural polymer. Aqueous solution of G-g-Am is a good flocculent for metallic ions. It can be used to bind Y3+, Ba2+ and Cu2+ to get a precursor for probable route for preparation of Y1 Ba2 Cu3 O7-x ceramic oxide superconductor. Complex formation for Y3+ or Ba2+ or Cu2+ with the polymer in this case has been understood from pH titration, conductometric titration and IR spectral technique. IR spectra shows involvement of – COO — group from side chain and -OH group from backbone of G-g-Am to bind polyvalent metal ion. From Nakamoto’s reference, for binding Cu2+, bidentate chelating nature of – COO —, for binding Ba2+ and Y3+, bidentate bridging nature of – COO — are expected. From charge neutralization, it is possible to understand that two – COO — (bidentate chelating) to bind Cu2+, four –COO— (bidentate bridging) to bind Ba2+ and six – COO — (bidentate bridging) to bind Y3+ are required. By considering involvement of -OH group from backbone, probable co-ordination number for cupric ion bound G-g-Am (G-g-Am-Cu2+) is 6, for G-g-Am-Ba2+ is 6 for G-g-Am Y3+ is 8.