Tailoring biochar supported iron nanoparticles to activate persulfate for atrazine degradation in soil

Persulfate (PS)-based advanced oxidation processes have attracted significant attention in the field of organic contaminant remediation. In this study, we developed a biochar-supported Fe nanoparticle catalyst (FeNPs@BC) characterized by a substantial quantity of Fe0, with the purpose of activating persulfate to facilitate the degradation of atrazine (ATZ) in soil. The results revealed that the 800 °C pyrolyzed FeNPs@BC-PS system, incorporating 2 wt% FeNPs@BC and 3 mmol/L PS, achieved rapid removal of ATZ (100%) within 10 min (kobs=0.19023 min-1). Active-species quenching experiments and electron spin resonance (ESR) demonstrated the presence of sulfate radicals (SO4•-), hydroxyl radicals (•OH), and singlet oxygen (1O2) in the FeNPs@BC-PS system. Furthermore, FeNPs@BC maintained a high catalytic activity even after four cycles of recycling. And the catalyst exhibited efficiency in degrading three other triazine herbicides (simazine, terbuthylazine, and ametryn). Notably, toxicity prediction experiments on the degradation products indicated lower toxicity compared to that of the parent ATZ. In summary, this study presents a promising solution for the development of an economical, efficient, and environmentally friendly technology capable of rapidly degrading soil herbicides.