Chitosan Schiff base iron-based complex aerogel for degradation of organic pollutants by efficient activated H2O2

The Fenton catalytic process represents a promising advanced oxidation technology for the degradation of recalcitrant organic pollutants; however, its practical application is limited by issues such as catalyst agglomeration and restricted pH tolerance. In this study, a chitosan-derived Schiff base iron aerogel (CS-C=N-Fe) was synthesized via a cost-effective and environmentally friendly method at ambient temperature. The coordination between the Schiff base ligand and iron effectively dispersed the active sites and mitigated Fe agglomeration. The obtained aerogel exhibited a high sulfamethoxazole (SMX) removal efficiency of 96.2 % within 210 min under near-neutral conditions, with an apparent rate constant of 0.0951 min −1 . The catalyst maintained more than 70 % degradation efficiency after six consecutive cycles, and 91 % SMX removal during 24 h of continuous operation in a flow system, showing excellent structural stability and resistance to coexisting ions. The total organic carbon removal reached 29 % within 60 min, indicating effective oxidative mineralization of SMX intermediates. Mechanistic studies confirmed that hydroxyl radicals were the dominant reactive species. Density functional theory calculations further revealed that H 2 O 2 adsorption and decomposition on the CS-C=N-Fe surface occur with favorable energies (−0.987 eV and −0.747 eV, respectively), supporting efficient H 2 O 2 activation. These results highlight the CS-C=N-Fe aerogel as a robust, recyclable, and scalable Fenton-like catalyst capable of operating efficiently across a broad pH range (3.0–9.0), offering practical potential for the treatment of antibiotic-contaminated wastewater.