Peroxymonosulfate activation by peanut shell biochar-doped BiFeO3 composite to remove antibiotic resistant bacteria from aquaculture wastewater

Abstract In this study, bismuth ferrite (BiFeO 3 , BFO) catalysts doped with different contents of peanut shell biochar (BC) were prepared and used in the removal of antibiotic-resistant bacteria (ARB) by peroxymonosulfate (PMS) activation from wastewater. The PMS (0.03 mM)/5% BC-BFO (0.5 g L −1 ) system removed 1.92 log ARB within 10 min of reaction at a reaction rate of 0.4401 min −1 . Raman spectra analysis revealed that 5% BC-BFO exhibited more defects and oxygen vacancies (Ov), which provided active sites for PMS activation to generate SO 4 ⋅− , O 2 ⋅− , and 1 O₂, thereby promoting ARB inactivation. The oxidation of PMSO to PMSO₂ suggests that high-valent iron-oxo species may also be involved in the inactivation of ARB. The PMS/5% BC-BFO system caused oxidative damage to the ARB cell membrane, increasing its permeability from 4.34% to 46.00%. Simultaneously, it triggered the activation of bacterial self-defense mechanisms and a cascade reaction, leading to the upregulation of intracellular reactive oxygen species (ROS) levels (rising from 6.34% to 62.90%), ultimately resulting in ARB inactivation. In addition, the ARB removal under PMS activation by the fourth recycled 5% BC-BFO catalyst was 62.6% of that by the fresh 5% BC-BFO. In summary, this study proposes a low-cost and easily synthesized novel catalyst for the efficient ARB removal from wastewater. Graphical Abstract