In Situ Cogrown Porous Composite Membrane for Pollutant Separation and Photocatalytic Degradation

Membrane separation technology has become a key approach in modern wastewater treatment, offering efficient solutions for removing organic pollutants. However, the accumulation of foulants on membrane surfaces remained a critical bottleneck, leading to flux decline, increased energy consumption, and reduced membrane lifespan. Unlike conventional membranes with only a pollutant separation function, our membrane simultaneously provided high rejection, high flux, and excellent self-cleaning capability in one material. We developed a PAN/porous organic polymers (POPs) composite membrane via an in situ cogrowth strategy. The successful incorporation of POPs was confirmed by various characterization techniques. The resulting membrane exhibited excellent photocatalytic activity under visible light, achieving 99% degradation of methylene blue (MB) within 90 min, far surpassing that of pristine PAN. Meanwhile, the membrane also showed outstanding dye rejection performance, with removal rates of 97% for MB and 86% for tetracycline (TC), along with a nearly doubled permeation flux (increased from 30 to 56 L·m–2·h–1 for MB and the TC flux increased from 25 to 58 L·m–2·h–1). More importantly, after five consecutive cycles, the membrane maintained stable separation performance, with rejection rates above 91% for MB and 79% for TC, and stable fluxes of 50 ± 5 L·m–2·h–1 (MB) and 47 ± 5 L·m–2·h–1 (TC), demonstrating excellent operational stability and self-cleaning capability. Overall, this study provides ideas for the design and practical application of visible-light-driven membrane catalysts and offers prospects for the use of membranes in actual water treatment and purification.