Degradation of antibiotic fosfomycin by peroxymonosulfate/ferrate and simultaneous phosphate removal with in situ formed ferric nanoparticles

This study systematically investigates the peroxymonosulfate/ferrate (Fe(VI)/PMS) system for efficient degradation of the antibiotic fosfomycin (FOS) and simultaneous phosphate removal via in situ formed ferric nanoparticles. The Fe(VI)/PMS system achieved complete FOS degradation within 10 min, with a pseudo-first-order rate constant (0.25 min-1) significantly higher than Fe(VI) alone (0.03 min-1) or Fe(VI)/peroxodisulfate (0.18 min-1). Reactive species, including SO4•-, HO•, and high-valent iron species (Fe(V)/Fe(IV), were identified as key contributors, with HO• playing a dominant role. Optimal conditions included 200 µM PMS, 100 µM Fe(VI), and pH 5.0–7.0. Natural water matrices (e.g., river water, wastewater effluent) slightly inhibited degradation, while seawater enhanced FOS degradation efficiency. Degradation pathways of FOS involve oxidation, bond cleavage, and coupling reactions, with by-products showing reduced toxicity. Notably, in situ formed ferric nanoparticles effectively removed released phosphate via co-precipitation, and post-treatment solutions exhibited negligible toxicity to E. coli. This study highlights Fe(VI)/PMS as a promising strategy for FOS remediation with simultaneous nutrient control.