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

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 0.09wt%, 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. © 2021, Editorial Office of Acta Materiae Compositae Sinica. All right reserved.