Kenji Sato, Wei Zhang

Solar-driven photocatalytic degradation represents a sustainable and eco-friendly paradigm for neutralizing recalcitrant organic pollutants and textile dye contaminants in industrial wastewater streams. This study reports the one-pot hydrothermal synthesis and structural characterization of binary titanium dioxide (TiO2) and graphitic carbon nitride (g-C3N4) heterojunction nanocomposites. X-ray diffraction, field-emission scanning electron microscopy, and UV-visible diffuse reflectance spectroscopy confirmed the successful formation of intimate interfacial contact between anatase TiO2 nanoparticles and 2D g-C3N4 nanosheets, significantly narrowing the optical bandgap to 2.45 eV. Photocatalytic performance evaluations under simulated solar light irradiation demonstrated that the optimal nanocomposite achieved a ninety-six percent degradation rate of rhodamine B and ciprofloxacin within eighty minutes, outperforming pristine commercial TiO2 by over 3.8-fold. Radical scavenger trapping experiments verified that photogenerated superoxide radicals and hydroxyl radicals act as primary reactive oxidizing species. The nanocomposite demonstrated robust cyclic reusability with negligible activity loss across five consecutive test cycles, highlighting its immense practical potential for scalable, decentralized wastewater treatment plants.