Impact of solution chemistry conditions on the sorption behavior of Cu(II) on Lin'an montmorillonite

In this study, the sorption of Cu(II) from aqueous solution onto Lin'an montmorillonite as a function of contact time, pH, ionic strength, foreign ions, humic acid (HA), fulvic acid (FA) and temperature was investigated under ambient conditions. The results indicated that the sorption of Cu(II) was strongly dependent on pH and ionic strength. The sorption of Cu(II) was dominated by ion exchange or outer-sphere complexation at low pH and inner-sphere complexation at high pH values. The presence of different cations had different influences on Cu(II) sorption, while the presence of different anions had no differentiable influences on Cu(II) sorption. The presence of HA and FA had no influence on the sorption of Cu(II) at pH<6, whereas it inhibited Cu(II) sorption at pH>6. The thermodynamic parameters (Delta H-0, Delta S-0, and Delta G(0)) were calculated from the temperature-dependent sorption isotherms and the results indicated that the sorption of Cu(II) on Lin'an montmorillonite is endothermic and spontaneous. (C) 2010 Elsevier BM. All rights reserved.