Graphene oxide was grafted with polyethylenimine (PEI) and subsequently blended with polyethersulfone (PES) to fabricate functional membranes with design surface properties. The synthesized GO-PEI additive was characterized with FTIR and XPS to confirm the successful grafting of PEI on GO. Zeta potential and size of GO-PEI were also analyzed. Subsequently, GO-PEI was mixed with PES in three different ratios to fabricate membrane through non-solvent phase inversion. Morphology of the prepared membranes was observed with both SEM and AFM. The chemical composition of the prepared membranes was characterized with XPS, indicating the presence of GO-PEI. More importantly, surface properties including hydrophilicity and surface charge of the prepared membranes were studied. The results indicated that with the increase of GO-PEI the membrane became more hydrophilic and more positively charged. Thus, we purposely prepared three membranes bearing negative, net zero and positive charges. The adhesion force between the prepared membranes and the negatively charged SiO2 AFM tip was studied through AFM force spectrometry. Four typical pollutants including phenanthrene, bovine serum albumin (BSA), Lysozyme and E.coli were used to evaluate the performance of the prepared membranes. In the static adsorption, surface charge more obviously affected the adsorption amount of pollutant than hydrophilicity. However, hydrophilicity indicated more obvious effect to prevent pollutant fouling in the dynamic filtration tests. In short, a novel graphene-based additive was synthesized to modify membrane surface property for different applications.

Novel graphene-based additive for membrane surface modification

255th National Meeting (2018)

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