Sludge-derived biochar applied in peroxymonosulfate (PMS) activation: Regulation of active sites and synergistic production of reaction oxygen species

Abstract

Sewage sludges and chlorophenols (e.g., 4-CP) generated from papermaking industries are polluting and hazardous. Nevertheless, the paper mill sludges possessed inherent iron and carbon components is expected to be converted into Fe/C-based peroxymonosulfate (PMS) activator for wastewater purification. In this study, the derived ferric-rich biochar materials paper sludge carbon (PSC) is synthesized via pyrolyzing paper mill sludge to activating PMS for 4-CP degradation in water matrix. The optimal PSC/PMS system exhibits about 100.00% 4-CP degradation efficiency and the kinetic constant reaches 0.1165 min^-1 while 66.82% of Cl^- is shed owing to high mineralization efficiency. Species trapping experiments and electron paramagnetic resonance spectra analysis indicate that the ¹O₂ and O₂^•− species dominate the 4-CP degradation. The high PMS decomposition and 4-CP degradation efficiency attribute to the Fe(II) and abundant defects. This study provides novel strategies for halogen removal and value-added utilization of paper mill sludge in environmental remediation.