Osman Urper, Nivedhitha Jothinarayanan, Mona Sæbø, Stephen Joseph, Kaiying Wang
Coexistence of organic dyes and pathogenic bacteria in wastewater demands integrated treatment, yet affordable, reusable photocatalysts that target both remain limited. In this study, biochar-supported TiO₂ (TiO₂/BC) and ZnO (ZnO/BC) nanocomposites were synthesized via a hydrothermal method to address this dual challenge. The incorporation of biochar enhanced dye adsorption and improved charge separation, leading to high photocatalytic degradation efficiency of methyl orange (up to 92% and 97%) under light irradiation. The nanocomposites retained over 80% and 90% of their activity after three reuse cycles, respectively for TiO₂/BC and ZnO/BC, demonstrating good stability. Additionally, the materials showed strong antibacterial activity against Escherichia coli , with inhibition rates reaching 90%. These results confirm the potential of the TiO₂/BC and ZnO/BC nanocomposites as sustainable, multifunctional materials for simultaneous pollutant degradation and water disinfection applications.