Extraction of metal ions using chemically modified silica gel: a PIXE analysis

Organic ligand with carboxyhydrazide functional group was immobilised on th e surface of silica gel and the metal binding capacity of the ligand-embedd ed silica was investigated. The functional group was covalently bonded to t he silica matrix through a spacer of methylene groups by sequential reactio ns of silica gel with dibromobutane, malonic ester and hydrazine in differe nt media. Surface area value of the modified silica was determined. The cha nges in surface area were correlated with the structural change of the sili ca surface due to chemical modifications. A mixture solution of metal ions [K(I), Cr(III), Co(II), Ni(II), Cu(II), Zn(II), Hg(II) and U(VI)] was treat ed with the ligand-embedded silica in 10(-3) M aqueous solution. The measur ement of metal extraction capacity of the silica based ligand was done by m ultielemental analysis of the metal complexes thus formed by using Proton I nduced X-ray Emission (PIXE) technique. (C) 2001 Elsevier Science B.V. All rights reserved.