Cotton-Supported UiO-66-NH2 Photocatalyst for Efficient Solar Degradation of Acetaminophen

Emerging pharmaceutical pollutants such as acetaminophen (ACE) pose health and environmental risks. Solar photocatalysis provides a sustainable and efficient treatment option. In this study, UiO-66-NH2 metal–organic framework was immobilized on cotton fabrics to enable their application in both batch and continuous flow systems. Cotton, a biodegradable and low-cost support, was first functionalized by two strategies: hydroxylation (-OH) and carboxylation (-COOH), to promote MOF anchoring. Cotton fabric functionalization and MOF growth were confirmed by ATR and X-ray diffraction, while SEM and EDX analyses revealed that carboxylated fibers achieved higher MOF loading. Photocatalytic experiments under simulated solar irradiation demonstrated significantly higher degradation of acetaminophen when the carboxylated cotton fabric-based catalyst (F-COOH-UiO-66-NH2) was used. Mott–Schottky analysis and band alignment revealed that, under the applied reaction conditions, hydroxyl radical generation was not favored due to the position of the valence band. Studies with scavengers identified the superoxide radical as the dominant oxidative agent responsible for the photodegradation process. In particular, the F-COOH-UiO-66-NH2 system demonstrated its suitability for application in continuous flow systems, achieving acetaminophen conversion of up to 50% under simulated solar irradiation. This confirms its potential for scalable application in practical water treatment technologies. These results reinforce the feasibility of immobilizing MOF-based photocatalysts on functionalized textile waste, offering a dual-purpose solution that combines the removal of pharmaceutical pollutants with the valorization of waste materials. The synergistic integration of high photocatalytic efficiency, sunlight harvesting and recyclability of the materials underlines the eco-friendly and cost-effective nature of the proposed strategy.