Photocatalytic Water Purification Using TiO₂/Graphene Nanocomposites Under Visible-Light Irradiation

Carlos Mendez; Qing Sun; Nadia Ibrahim

doi:10.55001/jams.v1i2.52

Abstract

Visible-light-active TiO₂/graphene nanocomposite photocatalysts are synthesized via a hydrothermal route with controlled graphene oxide reduction for efficient degradation of organic pollutants and bacterial inactivation in water. The optimized TiO₂/rGO composite (3 wt% reduced graphene oxide) exhibits a bandgap of 2.65 eV, extending light absorption into the visible region, and achieves 96.8% degradation of methylene blue (MB) within 60 min under simulated solar irradiation (AM 1.5G, 100 mW/cm²). Complete inactivation of E. coli (10⁶ CFU/mL) is achieved within 30 min, outperforming commercial P25 TiO₂ by a factor of 8.5. The enhanced photocatalytic activity is attributed to graphene-mediated electron-hole separation, extended visible-light absorption, and increased surface area (187 m²/g). Pilot-scale reactor testing (5 L volume) demonstrates sustained performance over 100 h of continuous operation with less than 12% activity loss.

Author Biographies

Carlos Mendez Institute of Chemical Research of Catalonia (ICIQ), Tarragona 43007, Spain

Carlos Mendez is a senior researcher at Institute of Chemical Research of Catalonia (ICIQ), Tarragona 43007, Spain. Their research focuses on machine learning, with over 24 publications in peer-reviewed journals.
Qing Sun School of Environmental Science and Engineering, Tongji University, Shanghai 200092, China

Qing Sun is a professor at School of Environmental Science and Engineering, Tongji University, Shanghai 200092, China. Their research focuses on advanced materials, with over 80 publications in peer-reviewed journals.
Nadia Ibrahim Water Research Center, American University of Cairo, Cairo 11835, Egypt

Nadia Ibrahim is an associate professor at Water Research Center, American University of Cairo, Cairo 11835, Egypt. Their research focuses on biomedical engineering, with over 50 publications in peer-reviewed journals.