Sorption and Selectivity Behavior of Some Rare Earth Elements on Bentonite-Dolomite Composites as Natural Materials

Sorption and selectivity behavior of Eu152+154(III), La(III), Ce(III), and Sm(III) on bentonite-dolomite (B:D) composites were studied using the batch technique. The effect of shaking time, pH, initial metal concentrations, and temperature on the uptake was examined. The best uptake of Eu152+154(III), La(III), Ce(III), and Sm(III) was reached at pH 4.5, with high separation factors at this pH. The kinetic data obey pseudo-second-order models. Langmuir model describes the uptake most adequately with the monolayer capacity of 26.87, 12.48, 9.17, and 7.42 mg g(-1) for Eu152+154(III), La(III), Ce(III), and Sm(III), respectively. The thermodynamic functions show that the sorption is endothermic and spontaneous. The studies show that B:D composites are suitable for the uptake of the ions under consideration from liquid solutions.