Fe-N co-doped highly graphitized biochar for peroxymonosulfate activation toward the degradation of persistent organic pollutants: Critical roles of singlet oxygen and electron transfer.

Herein, Fe-N co-doped highly graphitized biochar catalyst, which exhibits high catalytic activity toward peroxymonosulfate, was successfully synthesized via a simple one-pot pyrolysis method and applied for the efficient degradation of persistent organic pollutants. The co-doping of iron and nitrogen markedly increased the graphitization degree of the material, thereby enhancing peroxymonosulfate activation and achieving complete degradation of bisphenol A at an initial concentration of 20 mg/L within 40 min, which significantly outperformed other non-doped catalysts. Mechanism studies revealed that bisphenol A degradation via non-radical pathways (singlet oxygen and electron transfer) as the dominant mechanism. The proposed catalyst exhibited significantly enhanced stability, with performance comparable to or exceeding that of commercial catalysts. It was also successfully applied for the degradation of other persistent organic pollutants in real environmental water samples. Due to its robustness under broad working conditions, this catalyst holds significant potential for green environmental remediation.