The High Flux of Superhydrophilic-Superhydrophobic Janus Membrane of cPVA-PVDF/PMMA/GO by Layer-by-Layer Electrospinning for High Efficiency Oil-Water Separation

A simple and novel strategy of superhydrophilic-superhydrophobic Janus membrane was provided here to deal with the increasingly serious oil-water separation problem, which has a very bad impact on environmental pollution and resource recycling. The Janus membrane of cPVA-PVDF/PMMA/GO with opposite hydrophilic and hydrophobic properties was prepared by layer-by-layer electrospinning. The structure of the Janus membrane is as follows: firstly, the mixed solution of polyvinylidene fluoride (PVDF), polymethylmethacrylate (PMMA) and graphene oxide (GO) was electrospun to form a hydrophobic layer, then polyvinyl alcohol (PVA) nanofiber was coated onto the hydrophobic membrane by layer-by-layer electrospinning to form a composite membrane, and finally, the composite membrane was crosslinked to obtain a Janus membrane. The addition of GO can significantly improve the hydrophobicity, mechanical strength and stability of the Janus membrane. In addition, the prepared Janus membrane still maintained good oil-water separation performance and its separation efficiency almost did not decrease after many oil-water separation experiments. The flux in the process of oil-water separation can reach 1909.9 L m−2 h−1, and the separation efficiency can reach 99.9%. This not only proves the separation effect of the nanocomposite membrane, but also shows its high stability and recyclability. The asymmetric Janus membrane shows good oil-water selectivity, which gives Janus membrane broad application prospects in many fields.