巯基接枝氧化石墨烯/聚酰胺复合膜制备及反渗透脱盐性能

Fabrication of sulfhydryl grafted graphene oxide/polyamide composite membranes for reverse osmosis desalination

反渗透膜技术作为脱盐的核心技术,在海水和苦咸水淡化、超纯水制备、污水回水等领域具有广泛应用前景,但其渗透性-选择性之间的"trade-off"效应仍是限制反渗透技术发展的一大挑战。本研究将表面功能化(接枝巯基官能团)的氧化石墨烯(GO)掺入间苯二胺水相溶液中,通过水相间苯二胺和有机相均苯三甲酰氯界面聚合的方法制备出巯基接枝氧化石墨烯(GO-SH)/聚酰胺(PA)反渗透复合膜。利用TEM、SEM、EDS、FTIR和NMR对接枝后粉体进行表征,利用2 g·L^(-1) NaCl水溶液测试膜的脱盐性能,优化了界面聚合水相pH和反应时间的设定。研究结果表明,GO-SH能够更均匀地分散在PA中,优化后的pH为11,反应时间为4 min,当改性后粉体含量为0.09wt%时,复合膜水通量可达48 L·m^(-2)·h^(-1),脱盐率达到99.6%,相较于本实验接枝前纳米材料复合的PA膜分别提高了30%和2.54%。表面功能化的GO有效地解决了无机纳米粒子和有机聚合物的相容性,提高膜脱盐性能,有望进一步降低反渗透项目的运行成本。

As the core technology of desalination,reverse osmosis membrane technology has a wide application prospect in desalination of seawater and brackish water,preparation of ultra-pure water,sewage backwater and other fields.However,the"trade-off"effect between permeability and selectivity is still a major challenge to restrict the development of it.In this study,surface functionalized(grafted sulfhydryl group)graphene oxide(GO)was incorporated into m-phenylenediamine aqueous solution.Sulfhydryl grafted graphene oxide(GO-SH)/polyamide(PA)composite membranes were prepared by interfacial polymerization of m-phenylenediamine in aqueous phase and trimesoyl chloride in organic phase.TEM,SEM,EDS,FTIR and NMR were used to characterize the powder after grafting,and 2 g·L^(-1) NaCl solution was used to test the salt rejection property of the membrane,as well as the setting of pH and reaction time of interface polymerization aqueous phase was optimized.The results show that the GO-SH is more uniformly dispersed in the polyamide,the optimized pH is 11 and the reaction time is 4 min.When the modified powder content is 0.09 wt%,composite membrane water flux can be up to 48 L·m^(-2)·h^(-1) and the salt rejection reaches 99.6%,which are 30% and 2.54% higher than that of the GO/PA membrane in this study.Surface functionalized GO effectively solves the compatibility of inorganic nanoparticles and organic polymers,improves the membrane separation performance,and can be expected to further reduce the operating cost of reverse osmosis projects.