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

Abstract

This study systematically investigates the efficient degradation of the antibiotic fosfomycin (FOS) by a ferrate/peroxymonosulfate (Fe(VI)/PMS) system 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 that of 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 and wastewater effluent) slightly inhibited degradation, while seawater enhanced FOS degradation efficiency. The degradation pathways of FOS involve oxidation, bond cleavage, and coupling reactions, with by-products showing reduced toxicity. Notably, the in situ formed ferric nanoparticles effectively removed released phosphate via co-precipitation, and post-treatment solutions exhibited negligible toxicity towards E. coli. This study highlights the use of Fe(VI)/PMS as a promising strategy for FOS remediation with simultaneous nutrient control.