Mass Transfer-Enhanced Photothermal Membranes with Synergistic Light Utilization for High-Turbidity Wastewater Purification

Abstract

The photo-Fenton process faces significant limitations in treating high-turbidity, colored wastewater due to light attenuation and impurity interference (blocked mass transfer). To address these issues, we developed a suspended photothermal Fenton membrane by loading a photothermal catalyst on a hydrophobically modified cotton filter paper, enabling precise suspension 1 mm below the water surface. This design achieved 89.49 % light utilization and high chemical oxygen demand (COD) removal, even in wastewater with extreme chromaticity (10 multiples) and turbidity (703 NTU). The enhanced photothermal conversion accelerated molybdenum co-catalyzed Fenton reactions and improved peroxymonosulfate (PMS) activation, maintaining over 90 % phenol removal for 15 days. Mechanistic simulations revealed improved mass transfer of reactive oxygen species (ROS) and pollutants at the solid–liquid interface, with PMS diffusion identified as the rate-limiting step. The membrane resisted fouling from suspended solids and maintained stable operation in soil-containing solutions for 10 days. This innovative approach offers an efficient solution for degrading pollutants in dark-colored, high-turbidity wastewater, overcoming traditional process limitations.