Studies on the uranium removal from aqueous solution of contaminated soil using natural zeolite

Zeolite as a low-cost adsorbent for the removal of uranium (VI) ions from aqueous solution under the effect of various process parameters such as the pH of the intermediate, contact time, adsorption temperature, initial uranium concentration and S/L ratio. The equilibrium and kinetic characteristics of the Zeolite from acidic medium have been determined. The purpose of this investigation was to evaluate adsorption of uranium (VI) from soil pre-contaminated with them as well as their removal using different solutions. Citric, Maleic, Succinic, Tartaric, Lactic and oxalic organic weak acids were used for removal of metals from soil by washing. The soil samples were collected from the surface layer (0 - 30 cm) in field of Inchass area, Sharkia governorate, Egypt. Soils were pre-contaminated with 100 ppm uranium citrate. Experiment involved the application of the weak organic acids in amounts of 0.5 - 3.0% to evaluate the leaching efficiency for the uranium. The practical adsorption capacity of uranium upon the resin under the optimum conditions has been found to attain 32 mg/g which matches with Langmuir isotherm 35 mg/g. The physical parameters including the adsorption kinetics, the isotherm models and the thermodynamic data have also been determined to describe the nature of the uranium adsorption by the natural zeolite. The working natural clinoptilolite found to agree with both the pseudo second order reaction and the Langmuir isotherm.