Gradient Cross-Linking Graphene Oxide–Integrated Nanofiltration Polyvinylpyrrolidone Membrane for Polycyclic Aromatic Hydrocarbons Removal

Polycyclic aromatic hydrocarbons (PAHs) persist as organic contaminants within diverse water reservoirs, posing significant environmental and health risks. Nanofiltration (NF) membranes have emerged as effective tools for PAHs removal owing to their ability to separate based on size. However, membrane fouling and limited rejection efficiency remain as challenges. This study developed a novel gradient cross-linking graphene oxide (GO)–integrated polyvinylpyrrolidone (PVP) NF membrane to enhance PAHs rejection while mitigating fouling issues. The gradient cross-linking approach and GO integration are aimed at improving the membrane’s rejection performance, stability, and antifouling properties. Fourier transform spectroscopy spectra of the GO-PVP membrane showed new peaks, indicating the GO linkage. The membrane flux increased with GO concentration due to hydrophilicity; however, membrane flux decreased for the GO-PVP membrane at a loading of 0.5 wt% due to poor GO distribution. The results exhibited a higher membrane flux of 72.9 ± 2.9 L m⁻² h⁻¹, obtained for the GO-PVP membrane at 0.4 wt% loading. Salt rejection decreased with GO due to the development of large pores; hence, there is always a trade-off between membrane flux and salt rejection. GO-PVP membrane presents a promising approach for efficiently removing PAHs from water sources. The developed membrane has the potential to be applied in various water treatment applications, contributing to improved water quality and environmental protection.