Solar-driven photocatalytic ceramic membrane reactors from tunisian clay for efficient paracetamol degradation

Abstract

Pharmaceutical residues such as paracetamol are increasingly detected in aquatic environments, raising concerns about their persistence and potential ecological impact. In this study, a solar-driven photocatalytic membrane reactor (PMR) was developed using low-cost ceramic membranes fabricated from Matmata-Gabes clay (southern Tunisia) and functionalized with TiO 2 P25. The membranes were prepared by uniaxial pressing followed by sintering at 1000 °C, while TiO 2 was immobilized via dip-coating and calcined at 450 °C. The influence of catalyst loading and operating conditions was systematically investigated under both UV irradiation and natural sunlight. The results indicate that increasing TiO 2 loading improves surface hydrophilicity with the water contact angle decreasing to 17.5°, but excessive deposition reduces membrane porosity and permeability. Optimal performance was achieved at 0.6 g/L 1.0 and g/L of TiO 2 loading solution concentration under UV and solar conditions, respectively leading to degradation efficiencies of 74.9% and 55.5% after 5.5 h of treatment. In addition, horizontal membrane configuration (0° inclination) enhanced photon utilization resulting in improved reaction kinetics. Although permeate flux declined over time due to fouling, the photocatalytic layer contributed to partial self-cleaning under irradiation. Over five consecutive cycles, the membranes retained more than 35% of their initial activity, indicating moderate stability. These findings demonstrate the potential of combining locally available materials with solar photocatalysis as a sustainable approach for decentralized water treatment, particularly in regions with high solar irradiance.