Photo-Fenton and TiO 2 Photocatalytic Inactivation of Model Microorganisms under UV-A; Comparative Efficacy and Optimization.

Photocatalytic inactivation of pathogens in aqueous waste is gaining increasing attention. Several homogeneous and heterogeneous photocatalytic protocols exist using the Fenton's reagent and TiO, respectively. A comprehensive study of homogeneous and heterogeneous photocatalysis on a range of microorganisms will significantly establish the most efficient method. Here, we report a comparative study of TiO- and Fe-based photocatalytic inactivation under UV-A of diverse microorganisms, including Gram-positive () and Gram-negative () bacteria, bacterial spores ( spores) and viruses (MS2). We also present data on the optimization of TiO photocatalysis, including optimal catalyst concentration and HO supplementation. Our results indicate that both photo-Fenton and TiO could be successfully applied for the management of microbial loads in liquids. Efficient microorganism inactivation is achieved with homogeneous photocatalysis (7 mg/L Fe, 100 mg/L HO, UV-A) in a shorter processing time compared to heterogeneous photocatalysis (0.5 g/L TiO, UV-A), whereas similar or shorter processing is required when heterogenous photocatalysis is performed using microorganism-specific optimized TiO concentrations and HO supplementation (100 mg/L); higher HO concentrations further enhance the heterogenous photocatalytic inactivation efficiency. Our study provides a template protocol for the design and further application for large-scale photocatalytic approaches to inactivate pathogens in liquid biomedical waste.