Hydrogenated red mud biochar as visible-light-driven peroxymonosulfate (PMS) activators for efficient degradation of antibiotic: Resource utilization, mechanism insights and toxicity assessment

The drawbacks of low efficiency, high cost, and high energy consumption have always been main concerns for the treatment of antibiotic wastewater and massive solid wastes. In this work, a novel recyclable catalyst ((RM/ BC)H) was proposed by "To treat waste with waste" and "Resource oriented utilization of solid waste". Through hydrogenation and co-pyrolysis, the new catalyst was produced by industrial waste of red mud (RM) and biomass waste as the raw materials. And then, peroxymonosulfate (PMS) was activated by (RM/BC)H to degrade tetracycline hydrochloride (TCH) aqueous solution under LED-vis light condition. The results demonstrated that the (RM/BC)H + PMS + LED-vis light system has exhibited an excellent degradation efficiency with 82.6% for TCH (TOC removal efficiency 45.6%), and the efficiency kept stable at 80% after 5 cycles. Furthermore, EPR detection and quenching experiments revealed that SO4 center dot-, center dot OH, O2 center dot- and 1O2 were generated in this system and coparticipated in TCH degradation. Hydrogenation modification (RM/BC)H could improve the electron transfer efficiency and electric transfer ability of the materials. Meanwhile, the DFT calculations confirmed that Fe2+ was more conducive to the activation of PMS, and the synergistic effect of LED-vis light and PMS to form an internal cycle of Fe3+ and Fe2+ were favorable to the stability of the material. This study provides a feasible opinion on the economical and efficient degradation of antibiotic wastewater.