Towards the effective removal of environmental strains of bacteria from real wastewater by heterostructured photocatalysts

Abstract

Access to clean water is crucial for human health, yet microbial contamination poses significant challenges. This study investigates the effectiveness of novel photocatalytic catalysts: heterostructured TiO₂/AgBr and faceted titanium dioxide, for microbial inactivation under ultraviolet and visible light. Both catalysts were synthesized and characterized. Performance was evaluated using real wastewater samples and saline solutions, targeting gram-positive and gram-negative bacteria. The experimental approach included testing the photocatalysts with and without the addition of peroxydisulfate to assess its impact on inactivation effectiveness. Results indicated that the TiO₂/AgBr catalyst outperformed the faceted titanium dioxide one due to its superior visible light absorption and enhanced charge separation, achieving complete inactivation of environmental strains of Escherichia coli and significant inactivation for Enterococcus faecalis in real wastewater. The inclusion of peroxodisulfate with TiO₂/AgBr significantly improved inactivation rates, demonstrating a synergistic effect. Regarding wastewater composition, the treatment achieves a significant COD removal while the rest of studied parameters remain stable. Both catalysts effectively prevented bacterial regrowth for up to 48 hours, underscoring its long-term efficacy. Overall, these findings highlight the potential application of TiO₂/AgBr combined with peroxodisulfate as an effective strategy for microbial inactivation, contributing to the advancement in water treatment technologies across real environmental contexts.