Hybrid Photocatalytic Ultrafiltration Membranes: A Scalable Solution for CEC Removal

Contaminants of Emerging Concern (CECs), including pharmaceuticals, dyes, and plasticizers, persist in aquatic environments due to the limitations of conventional wastewater treatment technologies [1]. In Czechia, where industries such as textile dyeing and plastics manufacturing are prominent, persistent pollutants like Bisphenol A (BPA) and Rose Bengal (RB) have been detected at concerning levels [2]. This project introduces an innovative solution by developing a photocatalytic ultrafiltration membrane system capable of simultaneous degradation and separation of CECs under visible-light irradiation.
BiOI and BiOI-ZnO nanoparticles (NPs) were synthesized using a hydro-solvothermal method and incorporated into polyethersulfone (PES) flat-sheet membranes via the non-solvent-induced phase-separation (NIPS) technique. These nanocomposite membranes were integrated into a transparent cross-flow filtration module equipped with visible LED light sources to activate the photocatalysts. Membrane morphology, surface roughness, and hydrophilicity were characterized using SEM, EDX, AFM, and water contact angle measurements. Functional performance was evaluated through UV-Vis spectrophotometry, flux recovery tests, and antimicrobial assays.
The results demonstrated effective incorporation of NPs into the PES matrix, with BiOI and BiOI-ZnO showing strong photocatalytic degradation of BPA and RB under visible light. Colorimetric analysis revealed that the ZnO-modified membranes had the highest ΔE*, indicating enhanced dye removal efficiency. Additionally, all NP-modified membranes exhibited substantial antimicrobial activity against E. coli and Staphylococcus spp., even in dark conditions.
This hybrid membrane system offers a scalable, energy-efficient quaternary treatment solution, providing enhanced contaminant removal and antifouling capabilities. Its application has the potential to significantly improve wastewater treatment outcomes, particularly in regions facing high CEC loads, supporting sustainable water management practices.

Acknowledgements: This work was partly supported by the Student Grant Scheme at the Technical University of Liberec through project nr. SGS-2025-3580.