| Summary: | 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<sub>2</sub>, 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<sub>2</sub>- and Fe<sup>+3</sup>-based photocatalytic inactivation under UV-A of diverse microorganisms, including Gram-positive (<i>Staphylococcus aureus</i>) and Gram-negative (<i>Escherichia coli</i>) bacteria, bacterial spores (<i>Bacillus stearothermophilus</i> spores) and viruses (MS2). We also present data on the optimization of TiO<sub>2</sub> photocatalysis, including optimal catalyst concentration and H<sub>2</sub>O<sub>2</sub> supplementation. Our results indicate that both photo-Fenton and TiO<sub>2</sub> could be successfully applied for the management of microbial loads in liquids. Efficient microorganism inactivation is achieved with homogeneous photocatalysis (7 mg/L Fe<sup>+3</sup>, 100 mg/L H<sub>2</sub>O<sub>2</sub>, UV-A) in a shorter processing time compared to heterogeneous photocatalysis (0.5 g/L TiO<sub>2</sub>, UV-A), whereas similar or shorter processing is required when heterogenous photocatalysis is performed using microorganism-specific optimized TiO<sub>2</sub> concentrations and H<sub>2</sub>O<sub>2</sub> supplementation (100 mg/L); higher H<sub>2</sub>O<sub>2</sub> 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.
|
|---|