Lignosulfonate derived Fe-doped biochar activated peroxymonosulfate for tetracycline degradation: Solvent-free preparation, treatment efficiency and mechanism

Innovative engineering biochar from waste biomass is of huge interest for organic wastewater cleanup. This study introduced lignosulfonate (LS) derived Fe-doped biochar (Fe/LSB), which is prepared by the solvent-free method that integrating the ball-milling treatment with one-pot pyrolysis process, as the Fenton-like catalyst for tetracycline (TC) degradation. Various characterization revealed its porous structure, large surface area, and rich active sites. Degradation test confirmed that Fe/LSB achieves preferable efficiency for TC removal by peroxymonosulfate (PMS) activation. Mechanistic analysis identified a synergistic process involving 1 O 2 (mainly), SO 4 •– and •OH, which drove the effective TC degradation. Meanwhile, new degradation pathway in Fe/LSB/PMS system was proposed and the toxicity assessments revealed an obvious decline in toxicity of intermediate products. Furthermore, Fe/LSB/PMS system also achieved the excellent removal efficiency of TC during a continuous 6-day reaction process. This work transforms LS into Fe-based biochar catalyst, boosting sustainable development and providing a reliable way for TC removal, strengthening low-impact Fenton-like technology.