Effect of solution chemistry on the interaction of radionuclide 63Ni(II) onto montmorillonite

Sorption of 63Ni(II) from aqueous solution to montmorillonite as a function of experimental conditions was studied, and the results indicated that the sorption of 63Ni(II) was mainly dominated by ion exchange or outer-sphere surface complexation at low pH, and by inner-sphere surface complexation or surface (co)precipitation at high pH. The presence of different cations had different influences on 63Ni(II) sorption, whereas the presence of different anions had no drastic influences on 63Ni(II) sorption. The thermodynamic parameters indicated that the sorption of 63Ni(II) on the montmorillonite was an endothermic and spontaneous process.