A MIL-100(Fe)-modified flower-like Bi12O17Cl2 Z-scheme heterojunction photocatalyst with enhanced visible-light driven photocatalytic activity for norfloxacin removal

Abstract

With the aid of ultrasonic assistance, a flower-like Bi₁₂O₁₇Cl₂ photocatalyst modified with MIL-100(Fe) is created. The impacts of antibiotics, starting water sources, inorganic salt ions, and varying pH levels on the photocatalytic activity are investigated. Meanwhile, a variety of characterization methods are used for analyzing the morphology, chemical makeup, crystal structure, and optical characteristics. All of the Bi₁₂O₁₇Cl₂/MIL-100(Fe) photocatalysts with different Bi₁₂O₁₇Cl₂ contents show enhanced photocatalytic activity for norfloxacin (NOR) removal compared to monocomponent Bi₁₂O₁₇Cl₂. When the content of Fe element in MIL-100(Fe) accounts for 30 wt% of Bi₁₂O₁₇Cl₂, the catalyst achieves the highest NOR removal rate (86.30%). Its pseudo first-order kinetic constant is 2.06 times that of MIL-100(Fe) and 7.18 times that of Bi₁₂O₁₇Cl₂. To increase the catalyst's specific surface area, reactive active sites, visible light absorbance capacity and electron migration efficiency, MIL-100(Fe) was added, which improved the catalytic activity of the Bi₁₂O₁₇Cl₂/MIL-100(Fe). The findings demonstrate that the heterojunction's formation successfully increases the photocatalytic activity and prevents photogenerated electron–hole pairs from recombining. Finally, an electron transfer mechanism of the Bi₁₂O₁₇Cl₂/MIL-100(Fe) Z-scheme heterojunction was proposed by combining free radical trapping experiments and Mott Schottky curves.