Polyvinyl Alcohol/Graphene Oxide Nanocomposite Membrane for Highly Efficient Oil/Water Mixture Separation

Abstract

The growing amount of oily wastewater caused by frequent oil spill accidents poses a severe threat to the ecological environment. Therefore, the development of highly efficient oil/water separation methods is highly necessary. This work reports the preparation of a nanocomposite membrane using graphene oxide (GO)/polyvinyl alcohol (PVA) coated on steel meshes for oil/water mixture separation. PVA firmly anchors GO nanosheets onto the mesh surface through strong hydrogen bonds using glutaraldehyde (GA) as a crosslinker. This nanocomposite membrane exhibited superhydrophilic and underwater superoleophobic properties, with the highest oil contact angle of 158º due to its highly rough structure. The synergistic effects of GO and PVA further improved the superhydrophilicity of the prepared membrane, due to the hydrophilic nature of both GO and PVA. The separation efficiencies and water flux for a variety of oil/water mixtures were above 97.8% and 6000.0 L m⁻² h⁻¹, respectively. The prepared membrane showed excellent chemical resistance under harsh conditions without evident change in its surface wettability. Moreover, its underwater superoleophobicity was maintained after 10 cycles of abrasion testing.