CU AND PB ADSORPTION ON SOME BENTONITIC CLAYS

Cu2+ and Pb2+ adsorption isotherms were measured on some clay samples obtained from various regions of Turkey. Also specific surface areas o f clays were determined from adsorption data of ortho-phenanthroline(O P). The adsorptions of ions and OP were studied using the batch equili bration technique as a function of adsorbate concentration. The adsorp tion data, over the whole range of concentrations used, follow the Lan gmuir adsorption isotherm. The retention capacities of the adsorbates and the cation exchange capacities of the clays were determined. Plots of K-d, the distribution coefficient of ions between the solid and so lution phases, vs, Gamma, the surface density of adsorbed ions, showed that all the samples behave similarly: i.e. K-d sharply decreases wit h increasing values of Gamma. The amount of Pb2+ adsorbed is about 3-4 times that of CU2+ and the same adsorption capacity sequence was foun d for each ion.