ZIF-8基杂化膜的制备及其对水中金属离子的吸附

Preparation of ZIF-8-based hybrid membrane and adsorption of heavy-metal ions from water

采用溶胶-凝胶法制备了沸石咪唑酯骨架材料(ZIF-8),在此基础上制备了ZIF-8基杂化膜,采用XRD、FTIR、SEM和EDS等手段对其进行了表征,考察了杂化膜在单金属离子溶液及Pb^(2+)、Cu^(2+)和Cr^(3+)混合溶液中对金属离子的吸附效果。结果表明:在单金属离子溶液中,杂化膜对Pb^(2+)的吸附量最大;在混合溶液的竞争性吸附中,杂化膜D30(ZIF-8质量分数30%)室温下对Cu^(2+)吸附效果最好,对Cr^(3+)吸附效果略差,而对Pb^(2+)吸附效果更差,显示一定的优先吸附选择性。杂化膜D30对Cu^(2+)的吸附适合采用Lagergren准一级动力学模型进行描述,该吸附是一个吸热过程,可自发进行。

Zeolitic imidazolate framework-8(ZIF-8)was prepared by sol-gel method,and then the ZIF-8-based hybrid membranes were prepared.The hybrid membranes were characterized by XRD,FTIR,SEM and EDS and their adsorption effects for metal ions in single-metal solution and Pb^(2+),Cu^(2+),Cr^(3+)mixed metal solution were examined.The results demonstrate that the hybrid membrane has the largest adsorption quantity for Pb^(2+)in single-metal solution;In the competitive adsorption of Pb^(2+),Cu^(2+)and Cr^(3+)from mixed solution,the adsorption effect of hybrid membrane D30 with 30%of ZIF-8 mass fraction is best for Cu^(2+),worse for Cr^(3+),and more worse for Pb^(2+)at room temperature,showing a certain preferential adsorption selectivity.The adsorption of Cu^(2+)on hybrid membrane D30 follows Lagergren pseudofirst-order kinetic model,and the adsorption is a spontaneous endothermic process.