Bi3O4Br nanosheets immobilized in chitosan microspheres as efficient and recyclable hybrid catalysts for water treatment

Abstract

Access to clean water is a critical global priority. Thus, photocatalysis using semiconducting materials has emerged as a promising technology for wastewater treatment. Herein, a novel Bi₃O₄Br@Chitosan hybrid composite was successfully prepared by immobilizing Bi₃O₄Br in chitosan (CS) beads. First, Bi₃O₄Br was prepared via a solvothermal process, followed by its physical embedding in the CS matrix via a simple coprecipitation method. The surface morphology, elemental composition, crystal structure, and optical properties of the Bi₃O₄Br@CS material were comprehensively investigated using SEM, EDS, FTIR, XRD, TGA, zeta potential, Raman, and UV-vis spectroscopy, indicating excellent compatibility, multifunctional structure, and high structural robustness. Consequently, the Bi₃O₄Br@CS catalyst exhibits high efficiency in the UV-light-driven photodegradation of Rhodamine B (RhB), achieving 88% RhB degradation within 150 minutes and total reduction of 4-nitrophenol (4-NP) in the presence of NaBH₄ within 5 min at room temperature. Additionally, the catalyst shows good stability and can be reused over seven successive cycles without significant loss of activity. Therefore, the combination of adsorption capacity and photocatalytic activity within this hybrid catalyst provides an efficient and practical approach for wastewater treatment applications.