Hydroxyl Radical Generation by Recyclable Photocatalytic FeO/ZnO Nanoparticles for Water Disinfection

Abstract

Advanced oxidation processes based on photocatalytic generation of • OH radicals have emerged as promising technologies for the removal of recalcitrant pollutants in water. However, their poor recyclability has reduced their potential large-scale application. Herein, a Fe 3 O 4 -embedded ZnO system has been prepared and its photocatalytic • OH radicals activity was evaluated by monitoring the photo-assisted bleaching of p -nitrosodimethylaniline ( p NDA). Water disinfection performance was determined by measuring Escherichia coli inactivation under different conditions. Bleaching of nearly 80% of the initial p NDA concentration after just 120 minutes under UV 365nm irradiation was determined. Bacterial inactivation at different concentrations (0.1, 1.0, and 5.0 mg mL −1 ) of the Fe 3 O 4 /ZnO nanocomposite was determined, finding that the best performance was obtained at 0.1 mg mL −1 (90%) just after the first 30 minutes under UV irradiation. The materials are easily magnetically recovered and their performance evaluated after 3 consecutive cycles of reuse. These magnetic and photoactive nanocomposites showed improved performance and could be used for wastewater treatment or disinfection processes of water.