2D/1D Z-scheme heterojunction of Bi3O4Br and TiO2 nanobelt for photocatalytic degradation of pharmaceuticals

The pharmaceuticals present in wastewater treatment effluents cause significant environmental concern due to their persistence and potential toxicity. In the present work, a novel 2D/1D Z -scheme Bi 3 O 4 Br and TiO 2 nanobelt (Bi 3 O 4 Br/TiO 2 NB) photocatalyst was synthesized for the degradation of pharmaceuticals. Photocatalytic activity of this heterojunction catalyst was evaluated in the degradation of paracetamol and the effects of pH, photocatalyst dosage, pollutant concentration, and temperature were investigated. The Bi 3 O 4 Br/TiO 2 NB with a ratio of 2:1 enabled the highest 89 % degradation of paracetamol. Total organic carbon (TOC) analysis showed 54 % and 70 % TOC removal with 0.2 g and 0.4 g of the composite, respectively. Active species trapping experiments and electron paramagnetic resonance (EPR) analysis confirmed a Z -scheme charge transfer mechanism, improving charge carrier separation and increased generation of reactive oxygen species. Minimal structural degradation over four experimental cycles reflects the good stability of the composite. The degradation of diluted pharmaceutical wastewater using Bi 3 O 4 Br/TiO 2 NB decreased TOC by 21 % demonstrating the potential of the catalyst in the practical applications. • The optimized composite achieved 89 % paracetamol degradation under visible light. • 54 % TOC removal was obtained when 0.2 g Bi 3 O 4 Br/TiO 2 NB was employed. • Valence band XPS, radical trapping, and EPR verified a Z -scheme charge transfer. • 2:1 ratio resulted in improved lifetime and slowest recombination rate of carriers.