Chemisorption of Cu(II) chloride and nitrate in aqueous and non-aqueous solutions on matrix containing ethylenimine anchored on thiol modified silica gel surface

Matrix of silica gel organofunctionalized with thiol-ethylenimine group containing 2.60 mmol of nitrogen per gram of silica, caused extraction of CuX2 (X = Cl- and NO3-) from aqueous and non-aqueous solvents like ethanol, methyl ethyl ketone and acetonitrile at 298 +/- 1 K. Extraction was performed by the batchwise process whose maximum adsorption obtained showed the decreasing sequence methyl ethyl ketone > ethanol > acetonitrile > water for both salts. Cu(II) cation in all solvents was more adsorbed under nitrate form and the calculated selectivity (Gamma(n)) of the matrix related to Cu(II) was more than twice larger in the chloride form. The stoichiometry of the copper complex formed on the surface of the silica matrix was 1: 1 in nitrate counteranion, in all solvents we used. Thus, with respect to chloride counteranion the stoichiometry, metal:ligand, obtained was 1:1 in the solvents methyl ethyl ketone and ethanol, and 1:2 in acetonitrile and water. (C) 2002 Elsevier Science B.V. All rights reserved.