Selective removal of toxic and heavy metal ions like arsenic and copper from drinking water by using novel chelating resins immobilized on silica gel.

A new resin (o-HB-DAP-HCHO) obtained by condensing the Schiff base of o-hydroxybenzaldehyde-2, 6diaminopyridine (o-HB-DAP) with formaldehyde(HCHO) was used as polymeric ion exchange resin for separation and preconcentration of metal ions. The metal ion uptake studies were determined by spectrophotometry. To increase the efficiency of the resin it was immobilized on silica gel. By the impregnation of silica gel more coordinating sites are exposed to metal ions. The adsorption behaviour of the impregnated resins towards Cu (II), Ni (II), and Fe (III) was studied by batch as well as column techniques with the variation of different parameters. The conditions for separation of Cu (II) from a Cu (II)/Ni (II) mixture were ascertained. The resin showed more effectiveness in the adsorption process towards Cu (II) ions in both competitive and non-competitive conditions. Copper and iron polychelate of the resins are used as polymeric ligand exchanger to remove arsenate from drinking water. A comparative study was done between the copper and iron PLE. Various parameters influencing the removal of the arsenate ion from drinking water were studied.