Preparation of novel polysulfone-Fe3O4/GO mixed-matrix membrane for humic acid rejection

In this study, novel polysulfone-Fe3O4/GO mixed-matrix membrane was prepared by embedding the iron-decorated graphene oxide (Fe3O4/GO) into polysulfone (PSf) polymer. First, graphene oxide (GO) nanoplates were synthesized using natural graphite powder according to the Hummers method. Fe3O4/GO was then prepared by mixing both GO and Fe3O4 in the presence of ammonia hydroxide (NH4OH) according to co-precipitation method. A series of test, such as X-ray diffraction (XRD) and Transmission Electron Microscopy (TEM) were performed to characterize the produced Fe3O4/GO nano-hybrid. Mixed-matrix membrane was fabricated by casting the pre-mix PSf-Fe3O4/GO polymer solution mixture using phase inversion method. The performance of both neat PSf membrane and novel polysulfone-Fe3O4/GO mixed-matrix membrane were evaluated by measuring the membrane permeate flux and humic acid rejection. Experiment demonstrated that the novel polysulfone-Fe3O4/GO mixed-matrix membrane was having 3 times higher permeate flux than the neat PSf membrane despite the drop in humic acid rejection from 89 ± 2% to 84 ± 2%. However, polysulfone-Fe3O4/GO mixed-matrix membrane permeability was increased with the compensation of decreasing retention capacity due to pore size enlargement, higher porosity as well as higher hydrophilicity.