Fabrication and performance analysis of graphene oxide-based composite membrane to separate microplastics from synthetic wastewater

The pervasiveness of microplastics (MPs) jeopardize the entire environment and must be eradicated immediately. This study highlights the fabrication of a graphene oxide (GO)-polyvinyl alcohol (PVA) based composite membrane to separate high-density polyethylene (HDPE)-based MPs from wastewater using electrostatic repulsion mechanisms. The GO layers were stabilized by bonding with PVA using glutaraldehyde followed by deposition on a cellulose substrate via vacuum filtration. The bonding between GO and PVA via acetylation was confirmed by FTIR, while XRD indicated the well dispersion of GO in the PVA matrix. The surface morphology and composition of the composite membranes were analyzed using SEM and XPS respectively. Contact angle and zeta potential measurements were performed to confirm the hydrophilicity and negative surface charge of the membrane respectively. The optimum volume of the GO-PVA composite solution was used to control the membrane thickness, ensuring water permeation flux up to 179 L m2 h−1 bar−1 and maximize MP rejection. At pH 8 and 3 bar transmembrane pressures, 95 % of HDPE-MP rejection was observed in 15 s. These findings highlight the promising approaches for separating HDPE-based MPs from wastewater using GO-based composite membranes. [Display omitted] •Electrostatic repulsion between membrane and MPs increases the rejection rate.•The surface charge of MP varies with pH.•The successive increase of GO to 1 mg, gradually enhance MPs rejection by 10 %.•Inversely proportional relation exists between permeate flux and GO concentration.•Approximately 95 % of MPs could be separated using GO-PVA-based membrane.