Enhanced Heterogeneous Catalytic Activity of Peroxymonosulfate for Rhodamine B Degradation via a Co^II-Based Metal-Organic Framework

A stable metal-organic framework with the formula {[Co(BBZB)(IPA)]·H₂O} (JXUST-23, BBZB = 4,7-bis(1H-benzimidazole-1-yl)-2,1,3-benzothiadiazole and H₂IPA = isophthalic acid) was constructed by incorporating Co²⁺ ions and two conjugated ligands under solvothermal conditions. JXUST-23 takes a dinuclear cluster-based layer structure with a porosity of 2.7%. In this work, JXUST-23 was used to activate peroxymonosulfate (PMS) to degrade rhodamine B (RhB), a difficult-to-degrade pollutant in water. Compared with pure PMS or JXUST-23, the JXUST-23/PMS system displays the best degradation ability of RhB in neutral solution. When the mass ratio of JXUST-23 to PMS was 2:3, 99.72% of RhB (50 ppm) was removed within 60 min, and the reaction rate was 0.1 min^-1. Furthermore, free radical quenching experiments show that SO₄^•- was the main free radical during the process of RhB degradation. In addition, JXUST-23 exhibits good reusability for the degradation of the organic dye RhB, making it a potential candidate for environmental remediation.