Factors influencing retention of lanthanide ions by montmorillonite

Abstract

AbstractA method for the preparation of Ln-montmorillonite (Ln = La, Ce, Sm, Gd, Er and Y) that ensures saturation of the CEC is described and the most favourable equilibrium conditions are discussed. The H+- Ln3+ exchange rate in acid montmorillonite and the effect of concentration and pH on the retention of Ln3+ ions by the clay are also investigated. The presence of montmorillonite modifies the pH value at which precipitation of hydroxides begins, a process that actually occurs at pH ∼ 5.