Development of Functionalized Activated Carbon for Uranium Removal from Groundwater

Abstract

Some water wells used for drinking and other human activities in southwest Sinai, Egypt, recorded higher concentrations of uranium than the permissible levels. This paper focuses on uranium removal from groundwater. This target was utilized to develop an efficient and cost-effective graphite adsorbent (Graphite/AC), which was further altered by oxidation (O/AC) and amination (N/O/AC). Studying the controlling factors that affect the removal of uranium by O/AC and N/O/AC samples including, contact time, adsorbent amount, initial uranium concentration, solution pH, operational temperature, and the interfering of metal ions were tested and discussed. Dynamic and thermodynamics studies were achieved to predicate the performance of N/O/AC and O/AC for U(VI) removal from the groundwater samples. The activity of radionuclide (238U-series, 232Th-series and 40 K) and radioactive hazards indices of the groundwater samples were calculated and discussed. The developed materials showed good potential for the treatment of aqueous systems polluted by uranium, with 100 mg/g as maximum capacity. The thermodynamic parameters refer to the spontaneity and endothermic nature of the U(VI) ions adsorption process. A solution of 0.25 M HNO3 was found to be good enough for desorbing the adsorbed U(VI) from the adsorbents (96.8%). The positive effect of the used adsorbents (on the removal or minimizing the radioactive daughters consequently reduction of the hazard indices values) should be noted; this effect will be very helpful and effective with the old-age uranium concentrations.