Kinetic and Thermodynamic Studies on Uranium Ions Recovery Using Magnetite- Dowex 50WX8 composite

Batch Experiments on synthesized "Magnetite-Dowex 50WX8" composite were conducted to characterize its capability of uranium adsorption. The effect of pH, contact time, composite dose, initial uranium concentration and temperature on uranium adsorption rate was investigated to optimize the operation conditions of the synthesized composite. Thermodynamic and kinetic parameters have been studied. The maximum sorption capacity from Langmuir reached 200 mg/g at room temperature, pH 4, 25 mg of composite and 30 min. contact time. Uranium adsorption kinetics is well fitted to pseudo second order kinetic model at 500 mg/L uranium concentration. The change in the thermodynamic parameters (Delta G, Delta H and Delta S) indicates that the adsorption process is a spontaneous exothermic random process. Loaded hexavalent uranium ions were stripped from the loaded composite using 0.25M nitric acid. Optimum conditions were applied to purify the dissolved uranium content from a leaching solution of a granite sample from El-Missikat area, Central Eastern Desert, Egypt.