▎ 摘　　要

In this work, graphene oxide (GO) was first functionalized with branched polyethyleneimine (PEI). The obtained PEI-GO was incorporated into a brominated poly(2,6-dimethyl-1,4-phenylene oxide) (BPPO) matrix by a covalent bond interaction to form a cross-linking network. Then, a novel ultrafiltration (UF) membrane was prepared via casting and phase-inversion methods. The PEI-GO/BPPO membrane showed highly improved water flux, which was almost 6 times higher than that of the pristine BPPO membrane and 2.5 times higher than that of the GO/BPPO membrane, whereas the rejection of PEIGO/BPPO membrane was still maintained at a high level. The improvement of membrane performance could be attributed to the special property of PEI-GO and the interactions between PEI-GO and the BPPO matrix. First, a cross-linking network of PEI-GO/BPPO membrane was formed because of the reaction between PEI-GO and the BPPO matrix to provide passageways for water rapidly passing through. Second, the high hydrophilicity of PEI-GO could accelerate the exchange rate between solvent and non-solvent, resulting in a rougher and more hydrophilic surface, higher porosity and a more porous structure. Third, the good dispersion and compatibility of PEI-GO promoted the formation of a uniform structure with fewer defects. Proper molecular weight of PEI was very important for the modification of GO, subsequently resulting in an overall enhancement in membrane performance. Anti-fouling experiments and stability tests of the membranes were also conducted. All of these results were confirmed by various characterizations, such as SEM, TEM, AFM and, etc.