Experimental and modeling investigations of cesium and strontium adsorption onto clay of radioactive waste disposal

Migration of strontium and cesium radionuclide in geohydraulic system is important for safety disposal of radioactive waste containing of these two radionuclides to prevent the migration of radionuclides from the disposal site to provide protection for man and his environment. Geochemical analysis was carried out to investigate the mineral composition of the clay taken from the site to predict the historical and environmental geology of Inshas disposal site. Batch experiments were carried out as a function of pH, solute concentration and under three different temperatures (298 degrees, 313 degrees and 333 degrees K). Sorption capacity of Cs+ and Sr2+ onto clay sample was increased when initial metal ions concentration was increased. Increasing the temperature led to decrease in the sorption of Cs+ and Sr2+ ions. Several kinetic models were used to fit the experimental data and to examine the controlling mechanisms of the sorption processes. The kinetic study showed that sorption followed pseudo second-order model with a good correlation coefficient (R-2 = 0.999) for both studied ions. The experimental sorption data were fitted using Freundlich, Langmuir and Dubinin-Radushkevich (D-R) models. Results showed that the adsorption process was exothermic and favored at low temperature. (C) 2016 Elsevier B.V. All rights reserved.