An adsorptive photo-Fenton-like removal of 1,2-benzisothiazolin-3-one by NH2-MIL-53(Fe) under simulated solar light

Abstract

The excessive discharge of isothiazolinone bacteriostatic agent-containing wastewater has posed serious threats to human health and environmental safety. As 1,2-benzisothiazolin-3-one (BIT) is one of the most commonly used isothiazolinones, its effective degradation is necessary and urgent. In the current study, a NH₂-MIL-53(Fe)-based adsorptive photo-Fenton-like system was constructed for efficiently adsorbing and photodegrading BIT under solar light. The equilibrium BIT adsorption capacity Q_e of NH₂-MIL-53(Fe) reached 1140.89 mg g⁻¹. The adsorptive photo-Fenton-like system has achieved more than 90% removal of BIT using NH₂-MIL-53(Fe) in the presence of H₂O₂ under solar light irradiation, and the band gap of NH₂-MIL-53(Fe) was calculated by UV-Vis analysis to be 2.10 eV. The influences of pH, dosage of photocatalysts and H₂O₂ were also assessed. It was found that H₂O₂ reduced the recombination of electron–hole pairs, and the radical quenching experiments and EPR testing result confirmed that h⁺, ˙OH and O₂˙⁻ played a crucial role in the photocatalytic process. This study supports the application of Fe-based MOF materials for simultaneous adsorption and the solar light photocatalytic degradation of BIT.