络合-吸附方法去除核电厂模拟废水中的钴

Removal of Cobalt in Simulated Wastewater from Nuclear Power Plant by Complexation Enhanced Adsorption Process

针对核电厂放射性废水提出一种络合-吸附处理方法。初步采用乙二胺四乙酸(EDTA)作为有机络合剂、活性炭作为吸附剂、Co^(2+)作为去除对象,对该方法的可行性及相关影响因素进行了研究。结果表明,模拟废水中加入EDTA后可显著提高活性炭对Co^(2+)的去除率,符合理论预期,证实了该方法的可行性。络合-吸附条件实验结果显示,去除率随活性炭投加量的增大而增大;振荡16h后吸附达到平衡;溶液的pH值显著影响络合-吸附过程,最适宜pH值约为7.0;EDTA与Co^(2+)摩尔浓度比为1∶1时,Co^(2+)的去除率达到最大值。吸附特性研究结果显示,活性炭对EDTA-Co络合物的吸附热力学符合Freundlich模型,其吸附过程符合准二级动力学模型。

Complexation enhanced adsorption process was put forward to purify radioac- tive wastewater in nuclear power plant. EDTA was selected as the complexant, activa- ted carbon （AC） as the adsorbent and cobalt as the target nuclide to observe the feasibil- ity of this process and the impact of related factors. The results show that the removal rate after adsorption by AC improves remarkably by adding EDTA into the solution, which fits the theoretical expectation well and verifies the feasibility of this process. The results of conditional experiments show that the removal rate increases with the amount of AC, the adsorption equilibrium time is 16 h, the pH of the solution influences the processes of complexation and adsorption significantly, and the most suitable pH is about 7.0, and the highest removal rate is obtained with the molar concentration ratio of EDTA to Co2＋ of 1 ：1. The adsorption properties of AC for EDTA-Co complex were investigated by data fitting. The results show that the adsorption fits Freundlich isotherm model well, and the kinetic process of adsorption can be described by the pseu-do-second-order kinetic model.