In situ preparation of Mn-enriched biochar for catalytic degradation of ciprofloxacin via H2O2 activation

Phytoremediation is an effective strategy for removing heavy metals from contaminated soil; however, the subsequent disposal of metal-enriched plants remains a challenge. In this study, manganese-enriched biochar (MEB) was synthesized from Mn-enriched iris and employed as a catalyst to activate hydrogen peroxide (H 2 O 2 ) for the degradation of ciprofloxacin (CIP). Comprehensive characterization using SEM, BET, FT-IR, Raman, XPS, and HRTEM confirmed the successful synthesis of MEB, exhibiting favorable surface properties and catalytic stability. Under optimal conditions, the degradation efficiency of CIP (5 mg/L) reached 66.8 % within 120 min (pH = 6.7), with an observed rate constant ( k obs ) of 0.00895 min −1 , which was 4.2 times higher than that of Mn-doped biochar (MDB) prepared via an immersion technique. Scavenging experiments and electron paramagnetic resonance (EPR) analysis confirmed that •OH were the dominant reactive oxygen species responsible for CIP degradation. XPS analysis revealed that Mn active sites and sp 2 -hybridized carbon worked synergistically to enhance H 2 O 2 activation, thereby facilitating efficient •OH generation. 8 intermediate products were identified via LC-MS, and potential degradation pathways of CIP were proposed. Furthermore, The MEB/H 2 O 2 system exhibited strong anti-interference properties, sustaining high degradation efficiency despite variations in pH, common anions and the presence of humic acid, highlighting its excellent practical applicability. The superior catalytic performance, stability, recyclability, and low metal ion leaching of MEB highlight its significant potential for wastewater treatment applications involving H 2 O 2 activation. In situ preparation of highly dispersed Mn-enriched biochar for efficient catalytic degradation of ciprofloxacin. • Manganese-enriched biochar (MEB) synthesized from Mn-enriched iris catalyzed H 2 O 2 for CIP degradation. • Mn active sites and sp 2 carbon sites synergistically contributed to H 2 O 2 activation. • OH were identified as the dominant reactive species for CIP degradation. • The MEB/H 2 O 2 system maintained high performance in complex water matrices and varying conditions.