Efficient removal of ciprofloxacin from water by BiOX/GaMOF S-scheme heterojunction: A synergistic effect of adsorption and photocatalysis
Pengyuan Chen, Zhiqi Zhu, Zhao-Hui LIU, Fang-yu Liang, Xiang Zhu, Zhini Bin, Fangdi Huang, Nannan Wang, Yanqiu Zhu
Abstract
• MOF with enhanced adsorption capacity and stability centered around a gallium atom. • The adsorption capacity of BiOX for the antibiotic ciprofloxacin was significantly improved by the addition of GaMOF. • The S-scheme heterojunction of BiOX/GaMOF efficiently removes ciprofloxacin. • A predictive model for ciprofloxacin adsorption on GaMOF has been constructed. Human health is seriously threatened by the rising incidence of antibiotic resistance brought on by drug residues. A new BiOX/GaMOF photocatalyst with an S-scheme heterojunction was created using a hydrothermal process to solve this problem. The easily produced GaMOF can aggressively adsorb contaminants in water due to the high Lewis acidity of gallium and the huge specific surface area of MOFs, while the effective degradation capabilities of BiOX/GaMOF heterojunction allow for improved contaminant removal. Compared to pure BiOX, the optimized BG-15 exhibited a 400.53% improvement in adsorption performance, removing 50.42% of ciprofloxacin(CIP) within 60 min through adsorption alone. Moreover, the catalytic rate increased by 43.02%, and after 60 min of light irradiation following adsorption, 96.27% of CIP was removed from water. Isothermal adsorption models and theoretical calculations revealed three possible pathways for CIP adsorption on GaMOF. XPS, band structure, EPR, and experimental studies confirmed the formation of an S-scheme heterojunction in BG-15, and a photocatalytic mechanism involving OH, h + , O 2 − , and 1 O 2 as the main active species for CIP degradation was proposed. Photocatalytic treatment significantly reduced the ecotoxicity of degradation products, as confirmed by toxicity prediction and bacterial toxicity tests. This study demonstrates the potential of adsorption-photocatalysts for effective organic pollutant removal.