Benzothiadiazole functionalized Co-doped MIL-53-NH2 with electron deficient units for enhanced photocatalytic degradation of bisphenol A and ofloxacin under visible light

Abstract

Nowadays, designing highly active photocatalysts for pollutant degradation under visible light still remains a challenging problem. Herein, a novel benzothiadiazole functionalized Co-doped MOF-based photocatalyst with electron deficient unit was first synthesized via a feasible step-by-step assembly strategy. Benzothiadiazole, as typical electron deficient group, could effectively promote the separation and transfer of photoinduced charge carriers. The implantation of Co ion could be served as an effective mediator to further facilitate the charge transfer through a Co3+/Co2+ redox pathway. Interestingly, the as-synthesized Co-MIL-53-NH-BT exhibited significantly enhanced photocatalytic degradation capacity for BPA and OFX under visible light irradiation, with removal efficiency as high as 99.9 % and 99.8 % within 120 min. TOC analysis suggested that majority of contaminants had been degraded into CO2 and H2O. The important parameters influencing the photocatalytic activity were investigated, and the kinetics study was also conducted. The possible degradation pathways and the possible photocatalytic mechanism were proposed. More importantly, the as-synthesized Co-MIL-53-NH-BT showed good reusability, stability as well as universal applicability. To sum up, current work not only developed an efficient and visible-light active photocatalyst for treating organic-contaminated wastewater, but also afforded some novel insight into the utilization of benzothiadiazole in MOF-based photocatalyst towards improving photocatalytic activity.