Electron transfer mechanism of chitosan-modified natural manganese ore-cornstalk biochar composites with activated peroxymonosulfate: The role of functional groups on the surface of biochar-based composites

Biochar-based composite-driven advanced oxidation processes have important applications in wastewater purification. However, due to the complex structure of biochar-based composites, the mechanism of the emerging nonradical pathway is unclear. In this study, the functional groups on the surface of biochar composites were modified by the addition of chitosan to natural manganese ore- cornstalk biochar composites (CMCCX). Besides, the intrinsic structure–property relationship of biochar-based composite activated peroxymonosulfate (PMS) for the nonradical oxidation of bisphenol A (BPA) via electron transfer were revealed. Correlation linear fits to functional group content revealed that CC/CH on CMCCX was the active site for the metastable PMS generation, C-OH inhibited the generation of metastable PMS. Also, Mn-O, carboxyl, and hydroxyl groups influenced the electron transfer process from BPA to metastable PMS. Overall, the study prepared environmentally friendly biochar-based composites by a simple method and provided a reference for the preparation of biochar-based composites with tunable redox capacity.