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.

Graphic Abstract

中文翻译：

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开发功能性活性炭去除地下水中的铀

摘要

埃及西奈西南部的一些用于饮用和其他人类活动的水井记录到的铀浓度高于允许的水平。本文着重于从地下水中去除铀。该目标被用来开发一种高效且具有成本效益的石墨吸附剂（Graphite / AC），并通过氧化（O / AC）和胺化（N / O / AC）进一步加以改变。研究和讨论了影响O / AC和N / O / AC样品去除铀的控制因素，包括接触时间，吸附剂量，初始铀浓度，溶液pH，操作温度和金属离子干扰。通过动态和热力学研究来确定N / O / AC和O / AC去除地下水样品中U（VI）的性能。放射性核素的活性（²³⁸ 计算并讨论了地下水样品的U系列，²³² Th系列和⁴⁰ K）和放射性危害指数。所开发的材料在处理铀污染的水系统方面显示出良好的潜力，最大处理量为100 mg / g。热力学参数是指U（VI）离子吸附过程的自发性和吸热性。发现0.25 M HNO _3的溶液足以从吸附剂中解吸吸附的U（VI）（96.8％）。应当注意所用吸附剂的积极作用（减少或最小化放射性子体，从而降低危险指数值）；对于较老的铀浓度，这种效果将非常有帮助和有效。

图形摘要