Facile preparation of high performance GO/Mn3O4/PVDF composite membranes with intercalation of manganese oxide nanowires

Abstract

Polyvinylidene fluoride (PVDF) has been widely studied and applied in separation membranes due to its high thermal and chemical stability and mechanical strength. However, PVDF has strong hydrophobicity, resulting in easy contamination of the membrane surface and fast flux attenuation, so it is necessary to modify the membrane surface to improve its separation selectivity and service life. In this paper, PVDF microporous membrane was used as the matrix material and graphene oxide (GO) as the separation layer material. The GO/Mn₃O₄/PVDF composite membrane was prepared by layer self-assembly of GO nanosheets, and the functional layer spacing was adjusted by nanometer Mn₃O₄ intercalation. The prepared composite membrane showed high flux and separation selectivity in the filtration of organic compounds. The results showed that the rejection of methylene blue increased from 34% to 99.5%, and the flux decreased from 3000 L m⁻² h⁻¹ to 95 L m⁻² h⁻¹ when GO nanosheets covered the PVDF supporting membrane. After the introduction of Mn₃O₄ nanowires in the GO interlayer, the dye rejection reached 99.9% and the flux reached 612 L m⁻² h⁻¹. Compared with the unintercalated composite membranes, the flux of the prepared composite membranes showed good stability in the treatment of methylene blue, and the rejection remained unchanged.