Magnetic Pinecone Biochar‐Activated Peroxymonosulfate for Efficient Sulfamethoxazole Degradation: Performance, Mechanism, and Toxicity Analysis

ABSTRACT This study successfully prepared magnetic iron/cobalt codoped biochar catalyst (CFSBC) using a one‐step calcination method. The morphology and structure of the material were systematically characterized using SEM, XRD, FTIR, TEM, BET, Raman, VSM, and XPS techniques. The effects of key parameters such as catalyst dosage, peroxymonosulfate (PMS) concentration, initial pH, pollutant concentration, and coexisting substances on degradation performance were systematically investigated. The CFSBC/PMS system could remove 93.09% of sulfamethoxazole (SMX) within 60 min at a catalyst dosage of 0.05 g/L and a PMS concentration of 1 mM. The catalyst's excellent stability and universality were validated through the degradation of multiple antibiotics, real‐water applications, and cyclic experiments. Combining quenching experiments with electron paramagnetic resonance (EPR) analysis, singlet oxygen ( 1 O 2 ) and superoxide radicals (O 2 •− ) were identified as the primary active species in the reaction process. Electrochemical impedance spectroscopy (EIS) and linear sweep voltammetry (LSV) results, combined with theoretical calculations, confirmed the existence of a nonradical reaction pathway with an “electron‐bridging” architecture in the CFSBC/PMS system. Based on liquid chromatography–mass spectrometry (LC‐MS) identification of intermediate products, the possible degradation pathways of SMX were inferred, and the toxicity of degradation intermediates was analyzed using T.E.S.T. software.