Mechanistic study of oxidative removal of bisphenol A by pristine nanocatalyst Mn3O4/peroxymonosulfate

In recent years, activation of persulfate via Mn-based composites has gained interest due to extraordinary kinetics and performance for the degradation of organic contaminants. However, the potential of pristine manganese oxides (Mn3O4) in removing organic compounds and its mechanism has not been comprehensively explored yet. This study systemically investigated the Mn3O4 based peroxymonsulfate (PMS) activation to effectively mitigate bisphenol A (BPA) in different real water matrixes. Substantial mineralization (75.9%) with efficient removal of BPA (96.7%) has been achieved at optimum conditions in 60 min. A long-term performance, eight cycles of reusability, has shown merely an 11% reduction in BPA removal, highlighted the higher stability of Mn3O4. The oxidizing contributions of reactive oxygen species (ROS) were in the order of O-1(2) > O-2(center dot-) > SO4 center dot- > (OH)-O-center dot. The different water matrixes have influenced BPA degradation by<10%. Linear changes in BPA aromatic contents were recorded using log-transformed ultraviolet (UV) spectra and fluorescence excitation-emission matrix (EEM). Total 17 transformation products (TPs) were detected in Mn3O4/PMS/BPA system, with 13 decreasing concentrations and 4 TPs in increasing concentration with the beta-scission reaction as the main pathway for the degradation of BPA. The toxicity of BPA after degradation was also significantly suppressed measured by the activated sludge inhibition method.

Automated summary

This study investigated the effectiveness and mechanism of Mn3O4 based PMS activation for degrading BPA in water. Efficient removal of BPA and substantial mineralization were achieved under optimum conditions. Mn3O4 demonstrated high stability and reusability, with an 11% reduction in BPA removal after eight cycles of reuse.