College of Chemistry, Sichuan University, Chengdu 610064, PR China.
J Hazard Mater. 2011 Jun 15;190(1-3):442-50. doi: 10.1016/j.jhazmat.2011.03.066. Epub 2011 Mar 29.
A new sorbent for uranium(VI) has been developed by functionalizing ordered mesoporous carbon CMK-5 with 4-acetophenone oxime via thermally initiated diazotization. The sorption of U(VI) ions onto the functionalized CMK-5 (Oxime-CMK-5) was investigated as a function of sorbent dosage, pH value, contact time, ionic strength and temperature using batch sorption techniques. The results showed that U(VI) sorption onto Oxime-CMK-5 was strongly dependent on pH, but to a lesser extent, on ionic strength. Kinetic studies revealed that the sorption process achieved equilibrium within 30 min and followed a pseudo-first-order rate equation. The isothermal data correlated with the Langmuir model better than the Freundlich model. Thermodynamic data indicated the spontaneous and endothermic nature of the process. Under current experimental conditions, a maximum U(VI) sorption capacity was found to be 65.18 mg/g. Quantitative recovery of uranium was achieved by desorbing the U(VI)-loaded Oxime-CMK-5 with 1.0 mol/L HCl and no significant decrease in U(VI) sorption capability of Oxime-CMK-5 was observed after five consecutive sorption-desorption cycles. The sorption study performed in a simulated nuclear industry effluent demonstrated that the new sorbent showed a desirable selectivity for U(VI) ions over a range of competing metal ions.
一种新型的铀(VI)吸附剂是通过将 4-乙酰基苯肟通过热引发重氮化功能化有序介孔碳 CMK-5 制备的。采用间歇吸附技术研究了 U(VI)离子在功能化 CMK-5（肟-CMK-5）上的吸附，考察了吸附剂用量、pH 值、接触时间、离子强度和温度的影响。结果表明，U(VI)在 Oxime-CMK-5 上的吸附强烈依赖于 pH 值，但在一定程度上依赖于离子强度。动力学研究表明，吸附过程在 30 分钟内达到平衡，并遵循拟一级动力学方程。等温数据与 Langmuir 模型的相关性优于 Freundlich 模型。热力学数据表明该过程是自发和吸热的。在当前的实验条件下，发现最大 U(VI)吸附容量为 65.18mg/g。用 1.0mol/L HCl 可以定量回收负载 U(VI)的 Oxime-CMK-5，在连续 5 次吸附-解吸循环后，Oxime-CMK-5 的 U(VI)吸附能力没有明显下降。在模拟核工业废水中进行的吸附研究表明，新型吸附剂对 U(VI)离子具有良好的选择性，优于一系列竞争金属离子。
