Electric field endowing the conductive polyvinylidene fluoride (PVDF)-graphene oxide (GO)‑nickel (Ni) membrane with high-efficient performance for dye wastewater treatment

Abstract

Due to potential toxicity of the dyes and their visibility even at the very low concentration, treatment of dye wastewater has been a matter of considerable interest. Membrane technology is an emerging technology that offers a promising way to remove dyes from wastewater. However, the membrane fouling and trade-off effect severely hinder the removal efficiency. In view of this, the conductive polyvinylidene fluoride (PVDF)-graphene oxide (GO)‑nickel (Ni) composite membrane was firstly developed and implanted into the dead-end filtration cell as the cathode in the sandwich-like electrode. Under the assistance of electric field, the conductive PVDF-GO-Ni membrane displayed 98.02% Congo red (CR) rejection with the flux of 38.39 L·m−2·h−1·bar−1, which was an encouraging result comparing to most previous reports. Moreover, PVDF-GO-Ni membrane possessed certain antibacterial ability and super anti-adhesion ability to CR molecules. The underlying mechanism of super anti-adhesion of CR molecules was investigated by quantitatively calculating the interfacial interaction energy according to the extended Derjaguin–Landau–Verwey–Overbeek (XDLVO) theory. XDLVO theory indicated that the repulsive acid-based (AB) interaction energy between CR molecules and membrane surface predominantly facilitated the super anti-adhesion ability of the hydrophilic PVDF-GO-Ni membrane. The present study not only supplied a novel PVDF-GO-Ni membrane for high-efficient treatment of dye waste water, but also built an approach to quantitatively calculate interfacial interaction energy which should have a wide applications in forecasting and directing the modifications of separation membranes.