Polydopamine-functionalized metal-organic framework nanomaterials for enhanced ultrafiltration membrane performance in high-algae water treatment

Abstract

Mitigating membrane fouling during ultrafiltration of high-algae water is a significant challenge. This study addresses the issue by utilizing polydopamine-modified metal-organic framework (MOF) nanoparticles, specifically MIL-101, to fabricate a composite material known as PDA@MIL-101. A mixed matrix membrane, PES-PDA@MIL-101, was subsequently prepared through physical blending. The incorporation of PDA@MIL-101, characterized by its porosity, hydrophilicity, and electronegativity, significantly enhances the filtration performance and anti-fouling properties of the ultrafiltration membrane, making it highly effective for high-algae water treatment applications. The influence of the composite material on the membrane structure was evaluated at various mass ratios, focusing on its hydrophilicity, electronegativity, and pure water flux. Additionally, the performance of the modified ultrafiltration membrane was assessed in treating high-algae water and extracellular organic matter (EOM), with a detailed analysis of its fouling behavior. The results indicate that the composite material significantly altered the membrane structure, achieving a pure water flux of 440 L/(m2·h) at a 0.1 wt% loading. The modified membrane exhibited a UV254 rejection rate of 45 % for high-algae water and maintained a 16 % irreversible fouling rate over three cycles. Compared to the unmodified membrane, the pure water flux increased by 1.53 times, the UV254 rejection rate improved by 17 %, and the flux recovery rate for high-algae water rose by 15 %. Moreover, the modified membrane effectively mitigated pore blockage fouling caused by EOM, providing a solid foundation for the broader application of ultrafiltration membranes in high-algae water treatment.