High-performance ZIF-8 membranes:preparation and their uranium adsorption performance

高性能ZIF-8膜的制备及其铀吸附性能

In this study,the ZIF-8 membrane(ZIF-8/PP-g-MAH)is prepared by in situ synthesis of ZIF-8 on irradiation-pretreated polymer substrates to improve the uranium adsorption performance and address the recycling problems of ZIF-8 powder.The effects of pH,contact time,and uranium concentration on the adsorption of ZIF-8/PP-g-MAH were investigated.Adsorption isotherm and kinetics analysis show that ZIF-8/PP-g-MAH has a high adsorption capacity of 478.5 mg/g,which is 1.26 times higher than that of ZIF-8,and a rapid adsorption equilibrium of 120 min,which is shortened to one-third of that required for ZIF-8(360 min).The adsorption process of ZIF-8/PP-g-MAH is consistent with that of the Langmuir isotherm and pseudo-second-order dynamic model.ZIF-8/PP-g-MAH also exhibits good selectivity for uranium in simulated seawater.The high adsorption performance of ZIF-8/PP-g-MAH is attributed to its membrane structure,which improves the utilization of coordination sites,including Zn-OH,C-N,and C=N.This study provides an efficient adsorption material for rapid uranium extraction,thus promoting the development of uranium extraction technologies.

为开发高效铀吸附材料,实现从水相中快速高效提取铀酰离子,本工作通过在辐照接枝马来酸酐的聚丙烯纤维基体上原位生长ZIF-8,制备了ZIF-8复合膜(ZIF-8/PP-g-MAH),并研究了pH值、接触时间和初始铀浓度对ZIF-8/PP-g-MAH吸附性能的影响。吸附等温线和动力学分析结果表明,ZIF-8/PP-g-MAH的铀吸附容量高达478.5 mg/g,是ZIF-8粉末的1.26倍,并且其吸附平衡时间为120 min,缩短到ZIF-8粉末用时的1/3。吸附过程与Langmuir等温线和准二阶动力学模型一致。ZIF-8/PP-g-MAH对模拟海水中的铀也表现出良好的选择性。ZIF-8/PP-g-MAH表现出的高吸附性能归因于其膜结构提高了配位位点的利用率,包括ZnOH、C-N和C=N。此外,通过将ZIF-8与聚合物膜复合解决了MOF粉末回收再利用难题。本工作制备了一种可用于快速提铀的高效吸附材料,这将有助于推动提铀技术的进一步发展。