FeO loaded on ball milling biochar enhanced bisphenol a removal by activating persulfate: Performance and activating mechanism.

In this study, pristine biochar (BC), ball milling biochar (MBC), FeO modified BC (FeO@BC), and FeO modified MBC (FeO@MBC) were prepared to compare the Bisphenol A (BPA) removal efficiency by activating persulfate (PDS). All catalysts exhibited excellent degradation rather than adsorption in the PDS system, and FeO@MBC800 had the best BPA removal efficiency, with 96.73% degradation and negligible 1.43% adsorption due to the synergistic effect between MBC800 and FeO particles. Radical quenching experiments and electron paramagnetic resonance analysis indicated radical pathways, namely, SO∙ and ∙OH, O∙, and non-radical pathway (O) involving BPA degradation. The abundant oxygen-containing groups, increased graphitization and mesopores of MBC800, and Fe/Fe conversion of FeO particles facilitated PDS activation to produce reactive oxygen species. In addition, the superior electrochemical performance accelerated the electron transfer between the catalyst and PDS, promoting BPA degradation in the FeO@MBC800/PDS system. More importantly, FeO@MBC800 is resistant to environmental interference, including pH, anions, cations, and humic acid, and has good catalytic reusability and stability, which fulfills the requirements of engineering applications. Therefore, FeO loaded on ball-milled biochar provides a convenient strategy for preparing environmentally friendly, economical, and efficient carbon-based catalysts to remove organic contaminants.