Insights into heterogeneous catalysis of peroxymonosulfate activation by boron-doped ordered mesoporous carbon

Abstract

Sulfate radicals and/or hydroxyl radicals (SO4−∙ or ∙OH) have been generally demonstrated as the primary oxidative species in the activation of peroxymonosulfate (PMS). Recently, the role of singlet oxygen (1O2) on the degradation of pollutants has attracted increasing research attention. In this study, boron-doped ordered mesoporous carbon (B-OMC) was prepared and used to activate PMS for the removal of bisphenol A (BPA). Compared with the pristine OMC, the catalytic activity of B-OMC was greatly increased, which resulted from the enhanced adsorption capacity for BPA and the increased catalytic activity for PMS activation. On the one hand, B doping promoted the BET surface area and pore size of OMC; on the other hand, Lewis acid sites were introduced on the surface of OMC and acted as catalytic sites for PMS activation. Influencing factors, such as PMS concentration, catalysts dosage, reaction temperature and initial pH, on the removal of BPA were investigated. Combining the results of radical quenching experiments with electron spin resonance, it was verified that superoxide radical (O2−·) and 1O2 instead of SO4−∙ and ∙OH were the dominated oxidative species in B-OMC-PMS system. Electrochemical analysis demonstrated that the boron doping benefited from the electron transfer from B-OMC to PMS.