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

Abstract

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.

Facile Fabrication of Superhydrophobic Graphene/Polystyrene Foams for Efficient and Continuous Separation of Immiscible and Emulsified Oil/Water Mixtures

“…As seen in the SEM images in Figure 2 a, the GN/PSt composites contained interconnected polymer walls that formed large spherical pores ( Figure 2 a), and many smaller pores were present within the polymer skeleton ( Figure 2 b) [ 49 ]. GN randomly penetrated into the matrix of the porous materials, resulting in a rougher microstructure and lower surface energy ( Figure 2 c–f) [ 50 ]. Similar interconnected porous structures were seen in the GN 0 /PSt, GN 2 /PSt and GN 4 /PSt composites, which should be advantageous for the better transfer of substances through the porous materials when the monoliths are used to separate oil/water mixtures.…”

Study on the Preparation of Special Wettability Nanofiber Membranes and Its Application in Oil-water Separation

“…Wu et al [25] successfully prepared cross-linked polyvinyl alcohol/polyvinylidene fluoride/poly(methyl methacrylate)/graphene oxide (cPVA-PVDF/PMMA/GO) Janus membranes with opposite hydrophilicity by using electrospinning technique. This Janus membrane has excellent oil-water separation properties, and its separation efficiency has hardly decreased after several separation experiments.…”

Advances in Asymmetric Wettable Janus Materials for Oil–Water Separation

“…The JM presented high separation fluxes and separation efficiencies. Wu et al [ 43 ] also prepared a Janus membrane with excellent oil–water separation capacity via the electrostatic spinning technique. A mixture of polyvinylidene fluoride (PVDF), polymethyl methacrylate (PMMA), and graphene oxide (GO) was firstly electrostatically spun to form a hydrophobic layer, then polyvinyl alcohol (PVA) nanofibers were coated on the hydrophobic membrane by the layer-by-layer electrostatic spinning to form a composite membrane.…”