Iron-rich natural mineral waste enabling the photocatalytic activation of peroxymonosulfate for the oxidation of Enterococcus faecalis and tetracycline

This study investigates the photocatalytic potential of a mining residue containing various iron oxides. The material was applied in an advanced oxidation process (AOP) based on peroxymonosulfate (PMS) activation under simulated solar irradiation for the inactivation of Enterococcus faecalis (E. faecalis) and the simultaneous removal of tetracycline (TC) from wastewater. Complete inactivation of E. faecalis was achieved with a mineral waste (MW) dose of 0.5 g/L after 120 min of irradiation. By adding 0.05 mM PMS, similar disinfection efficiency was maintained while reducing the MW dose to 0.25 g/L and the treatment time to 90 min. Photocatalytic activation of PMS by Fe 2+ ions released from the metallic oxides generated reactive species with sufficiently high oxidation potential to degrade the contaminants present in the sample. Under optimal conditions, the MW/PMS/Solar system demonstrated outstanding performance in the simultaneous removal of E. faecalis and TC, with a higher affinity toward TC, achieving a 92.77% removal rate in just 30 min. The system also exhibited sensitivity to the initial pH, where deviations toward acidic or basic conditions led to reduced inactivation efficiency of E. faecalis . When applied to a real wastewater sample, the MW/PMS/Solar system showed promising results, highlighting its potential as an efficient, sustainable, and low-cost disinfection approach. • Mining waste with iron oxides acts as an efficient solar photocatalyst. • Complete Enterococcus faecalis inactivation achieved using MW/PMS/Solar. • Fe 2+ -activated PMS generates reactive species for disinfection and TC removal. • Simultaneous removal of bacteria and tetracycline reached 92.8% in 30 min. • Effective performance in real wastewater highlights a low-cost AOP strategy.