Engineering hybrid photocatalytic-membrane reactor for enhanced removal of pharmaceutical and PFAS from aquatic matrices

Organic micropollutants in the aquatic environment and their possible effects on living organisms has emerged as a serious environmental concern, particularly as conventional wastewater treatments can only partially remove these contaminants. Among various emerging treatment technologies, semiconductor photocatalysis represents a promising solution due to its ability to achieve complete degradation of organic pollutants through the generation of reactive oxygen species (ROS), offering a sustainable alternative to most classical technologies. This study investigates ultraviolet-based (UV) treatment methods, including direct photolysis and heterogeneous photocatalysis, for the removal of pharmaceutical micropollutants (Diclofenac, Carbamazepine, Paracetamol) and per- and polyfluoroalkyl substances (Pentadecafluorooctanoic Acid, Ammonium Perfluoro, Heptafluorobutyric Acid) in deionized water and wastewater matrices. Experiments were conducted under UVA and UVC irradiation using titanium dioxide and hexagonal boron nitride as photocatalysts in batch and continuous configurations. Key results demonstrate that TiO₂/UVA achieved complete Diclofenac degradation (100% in 45 min, k = 0.217 min⁻¹) and high pharmaceutical mixture removal (84–93% in DI), outperforming h-BN (≤37% adsorption-driven removal). PFAS resisted degradation across all conditions, highlighting C–F bond recalcitrance. Wastewater matrices reduced efficiency due to dissolved organic matter (DOM) interference, scavenging of reactive oxygen species, and competition for catalyst active sites, which limited photocatalytic activity. A continuous membrane-integrated system (2 L reactor, 400 mg L⁻¹, TiO₂, UVA) achieved 77% DCF removal at 70.8-min hydraulic residence, enabling catalyst retention and scalable operation. The system demonstrates the feasibility of pharmaceutical removal in energy-efficient water treatment, though PFAS persistence demands alternative strategies.