Surface modified silica gel for extraction of metal ions: an environment friendly method for waste treatment

A surface modified silica gel chelating resin was synthesised by immobilising tetracycline (TCN) on the surface of modified silica gel to produce a granular sorbent for the adsorption and estimation of copper, nickel and cadmium. Metal ions were quantitatively retained on the column packed with immobilised silica gel in the pH ranges of 5.0-6.5 for Cu, 6.8-7.8 for Ni and 6.6-7.8 for Cd. The distribution coefficient D determined for each metal ion was as follows (mL g(-1)): Cu, 2.45 x 10(2); Ni, 1.84 x 10(2); Cd, 2.33 x 10(2). Methods have been developed to determine copper, nickel and cadmium in steel, medicine tablets, alloys and river water samples. Molecular modelling studies were also performed on TCN-imobilised silica gel for gaining an insight into the active structure of TCN on the silica surface.