5,11,17,23,29,35-六羧基-37,38,39,40,41,42-六羟肟酸甲氧基杯[6]芳烃对铀(Ⅵ)的萃取

Extraction of uranium(Ⅵ) with 5,11,17,23,29,35-hexacarboxy-37,38,39,40,41,42-hexa-methoxy-hydroxamic calix[6]arene

以上沿羧基化的杯[6]芳烃羟肟衍生物-5,11,17,23,29,35-六羧基-37,38,39,40,41,42-六羟肟酸甲氧基杯[6]芳烃(HHMHC)为萃取剂,利用HHMHC萃取U(Ⅵ),探讨U(Ⅵ)溶液初始p H值、萃取剂浓度、温度、萃取时间、初始U(Ⅵ)浓度等因素对HHMHC萃取U(Ⅵ)的影响。实验结果表明,在萃取剂浓度为2×10-4mol/L,U(Ⅵ)初始浓度为2.1×10-5mol/L,温度为25℃时,HHMHC萃取U(Ⅵ)的最佳p H值为6.0,萃取平衡时间为30 min,且最佳萃取分配比大于10。用准二级动力学模型(R2>0.99)和Freundlich等温模型(R2>0.999)均可较好地拟合其萃取过程,通过计算萃取过程的热力学参数焓变(ΔH0)小于0,表明此萃取反应是一个放热反应。以0.1 mol/L的HCl溶液作为反萃取液,初次反萃取率达96%,证明HHMHC具有一定的重复利用价值。

5,11,17,23,29,35-hexacarboxy-37,38,39,40,41,42-hexa-methoxy-hydroxamic calix[6]arene（ HHMHC） was used as extractant to extract uranium from aqueous solution. The influences of p H,initial concentration of HHMHC,temperature,extraction time and initial uranium concentration on the extraction of U（ VI）with HHMHC were investigated. The results showed that when under the experiment conditions of 25℃,an extractant concentration of 2 × 10- 4mol / L,and an initial uranium concentration of 2. 1 × 10- 5mol / L,the optimal conditions were found to be 30 min of contact time,p H = 6. 0,and the maximum extraction distribution ratio was over 10. The equilibrium date fitted well with the pseudo-second-order model（ R2 0. 99） and Freundlich model（ R2 0. 999）. In the extraction process,the negative values of ΔH0revealed that the nature of extraction was exothermic. The extractant could be reextracted by 0. 1 mol / L HCl and the first reextraction rate was up to 96%,indicating that this extractant has a good prospect in the treatment of uranium-containing wastewater.