Hydrophilicity, morphology and excellent adsorption ability of poly(vinylidene fluoride) membranes induced by graphene oxide and polyvinylpyrrolidone

In this work, graphene oxide (GO) and polyvinylpyrrolidone (PVP) were introduced into poly(vinylidene fluoride) (PVDF) membranes that were prepared through phase inversion induced by immersion precipitation technique. The effects of GO and PVP on hydrophilicity, pore morphology and porosity of membranes were systematically investigated. The results demonstrated that GO and PVP exhibited synergistic effects in controlling the hydrophilicity, morphology and porosity of composite membrane. Largely enhanced hydrophilicity and porosity were simultaneously achieved for the PVDF/PVP/GO composite membrane. Furthermore, the effects of GO content on the morphology and porosity of composite membranes were also investigated. It was found that increasing GO content not only induced apparent changes of pore morphology but also induced the increase of the porosity of composite membrane. The adsorption ability of membranes were evaluated by immersing membranes in the solution of Methylene blue. It was found that the PVDF/PVP/GO composite membrane exhibited excellent adsorption ability for Methylene blue particles. The more the GO in the composite membrane was, the better the adsorption ability was. This work provides a highly effective method to greatly improve the hydrophilicity and adsorption ability of PVDF-based composite membrane with great potential in the field of wastewater treatment.