Han Dong, Li Xingxiao, Cui Yu, Yang Xin, Chen Xibang, Xu Ling, Peng Jing, Li Jiuqiang, Zhai Maolin
Beijing National Laboratory for Molecular Sciences, Radiochemistry and Radiation Chemistry Key Laboratory of Fundamental Science, The Key Laboratory of Polymer Chemistry and Physics of the Ministry of Education, College of Chemistry and Molecular Engineering, Peking University Beijing 100871 China
State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, School of Public Health, Xiamen University Xiamen Fujian 161102 China.
RSC Adv. 2018 Mar 5;8(17):9311-9319. doi: 10.1039/c8ra00838h. eCollection 2018 Feb 28.
The removal of TcO from aqueous solutions has attracted more and more attention recently, and ReO has been widely used as its natural analog. In this work, polymeric ionic liquid gel adsorbents, PC-CvimBr, with high adsorption capacity and selectivity towards ReO were synthesized by radiation-induced polymerization and crosslinking. PC-CvimBr was composed of two monomers: a hydrophobic unit, 1-vinyl-3-dodecylimidazolium bromide for high selectivity, and a hydrophilic unit, 1-vinyl-3-ethylimidazolium bromide for improved kinetics. A gel fraction up to 90% could be achieved under 40 kGy with varied monomer ratios. The adsorption of PC-CvimBr gels for ReO was evaluated by batch adsorption. The PC-CvimBr gel containing 20 mol% hydrophilic unit (named PC-CvimBr-A) could significantly improve the adsorption kinetics, which had an equilibrium time of 24 h. The adsorption capacity obtained from the Langmuir model was 559 mg g (Re/gel). The selective factor against NO was 33.4 ± 1.9, which was more than 10 times higher than that of PCvimBr, and it could maintain ReO uptake as high as 100 mg g in 0.5 mol kg HNO. The ΔH and ΔS of the NO /ReO ion-exchange reaction of PC-CvimNO-A were -16.9 kJ mol and 29 J mol K, respectively, indicating physical adsorption. The adsorption mechanism of ReO onto PC-CvimBr-A gel was ion-exchange, and it could be recovered using 5.4 mol kg HNO.
近年来，从水溶液中去除高锝酸根（TcO）越来越受到关注，高铼酸根（ReO）作为其天然类似物已被广泛应用。在本工作中，通过辐射诱导聚合和交联合成了对ReO具有高吸附容量和选择性的聚合离子液体凝胶吸附剂PC-CvimBr。PC-CvimBr由两种单体组成：疏水性单元1-乙烯基-3-十二烷基咪唑溴盐用于提高选择性，亲水性单元1-乙烯基-3-乙基咪唑溴盐用于改善动力学。在40 kGy下，通过改变单体比例可实现高达90%的凝胶分数。通过分批吸附评估了PC-CvimBr凝胶对ReO的吸附。含有20 mol%亲水性单元的PC-CvimBr凝胶（命名为PC-CvimBr-A）可显著改善吸附动力学，其平衡时间为24 h。从朗缪尔模型获得的吸附容量为559 mg g（Re/凝胶）。对硝酸根（NO）的选择性因子为33.4±1.9，比PCvimBr高10倍以上，并且在0.5 mol kg硝酸中，它对ReO的吸附量可保持高达100 mg g。PC-CvimNO-A中NO/ReO离子交换反应的ΔH和ΔS分别为-16.9 kJ mol和29 J mol K，表明为物理吸附。ReO在PC-CvimBr-A凝胶上的吸附机制为离子交换，并且可用5.4 mol kg硝酸进行回收。
