URANIUM SORPTION ONTO SOME SEDIMENTS AND ITS REMEDIATION

Abstract

The purpose of this investigation is to study how to remove and/ or reduce uranium pollution in certain area in Sinai (Wadi Um Hamad, southwest Sinai, Egypt). Two methods were tried: 1- Chemical method in which natural clay deposits were used before and after their modification. 2- Phytoremediation using sunflower plant. In the first method, two different kinds of deposits, kaolinitic dominant sediment while other is smectite dominant one. In this experiment both deposits were used before and after their modification. Modification involved acid activation and calcination. The second remediation method is the phytoremediation in which sunflower plant was used in pots experiment. This investigation involved also, studying factors affected adsorption and desorption of uranium by the modified and non-modified sediments such as: concentrations of adsorbate, temperature, pH, contact time and quantities of adsorbents. Also, sequential extraction of uranium adsorbed by different constituents of the sediments, i.e., organic, carbonate, exchangeable, oxides and residue, were estimated. In the following are some of the obtained results: - Um Hamad sediments have sandy loam texture, non-saline, but alkaline (pH= 8). Total and available uranium are 260 ppm and 28 mg/l, respectively.

- Adsorption of uranium was highest at pH 5 and 6 by kaolinitic and smectitic sediments, respectively. U adsorbed by smectitic sediments is higher than that adsorbed by kaolinitic one. especi