Bismuth (III)-based metal-organic framework for tetracycline removal via adsorption and visible light catalysis processes

At present, studies on metal-organic frameworks (MOFs) have mainly focused on transition metals and lanthanides. In this study, the main group element bismuth (Bi) with low toxicity, low cost, light response, and good chemical stability was used as the metal center, and terephthalic acid was used as the ligand to prepare bismuth terephthalate material (BiBDC) through a hydrothermal method for the adsorption and photocatalytic degradation of tetracycline (TC). Under visible light irradiation, approximately 92.4% of TC (10 mg/L) was removed within 40 min through the synergistic effect of adsorption and photocatalytic degradation process. The entire process of TC removal could achieve sustainable environmental remediation without the need for additional oxidants. Meanwhile, after 5 cycles BiBDC still reached over 74% TC removal. The zeta potential, BET, FT-IR, and XPS analysis results confirmed the interaction between TC and BiBDC, in which the TC adsorption mechanism on BiBDC mainly involved pore-filling, electrostatic interactions, complexation, and H-bonds. The results of free radical trapping and EPR experiments showed that h+ played the dominant role in the photocatalytic degradation of TC, and·O2- also contributed to this process. In addition, BiBDC showed better TC removal performance in natural water bodies. This study provides some implications for the construction of BiBDC as a novel and promising dual-functional material for the elimination of pollutants in water treatment.