Bi₂₄O₃₁Br₁₀/Ni-MOF-74 heterojunction: construction and simultaneous photocatalytic degradation of ciprofloxacin and methyl orange

Construction of highly efficient photocatalysts is essential for the degradation of diverse organic pollutants emanating from accelerated industrialization. This study addressed the ciprofloxacin (CIP) antibiotic and Methyl Orange (MO) organic contaminants remediation by a constructed abundant oxygen vacancy-rich Bi₂₄O₃₁Br₁₀/Ni-MOF-74 heterojunction (BOB-N) via a facile hydrothermal reaction. The BOB-N constructed heterojunction confirmed that BOB nanosheets were uniformly distributed on the surface of Ni-MOF and shortened the electron migration distance, based on characterizations (SEM, XRD, FTIR, and XPS). The photocatalytic activities of as-prepared BOB-N composites for the degradation of CIP and MO were carried out in a photo-reactor under UV irradiation intensity of 90 mW/cm² for 40 and 80 min, and the effects of various operating parameters (pH, inorganic anions, and light reactors) were investigated. The results showed enhanced CIP (98.39%) in the BOB-N composites compared to MO (95.30%), with BOB-N-12.5% the optimized photocatalyst in this study. The alkaline pH (11) region was most suitable for CIP and MO degradation, especially at a concentration of 20 mg/L. The NO₃^- anion (5 mM) had a negligible effect on the CIP degradation process compared to other inorganic anions. The CIP degradation under UV light (98.38%) was more effective compared to the light-emitting diode (LED) reactor. The trapping studies for active species indicated that holes and superoxide radicals significantly contributed to the breakdown of CIP.