EDTA-modified zero-valent iron activated peracetic acid for sulfamethazine removal: Performance and mechanism

Abstract

In this study, we utilized EDTA-modified zero-valent iron (EDTA-Fe0) to activate peracetic acid (PAA) for the removal of sulfamethazine (SMT) under neutral pH condition. We found that EDTA-Fe0 greatly enhanced the activation of PAA for SMT removal compared to the Fe0. Within 30 min, EDTA-Fe0/PAA system removed 97.0 % SMT, while Fe0/PAA system only removed 28.2 % SMT. Characterization and density functional theory (DFT) calculations confirmed that EDTA-Fe0 could enhance PAA activation thereby improving antibiotics removal. Radical quenching experiments and electron paramagnetic resonance spectroscopy (EPR) tests revealed that OH, R–O, and Fe (IV) all played a crucial role in SMT removal in the EDTA-Fe0/PAA system. Toxicity analysis demonstrated that the degradation of SMT by the EDTA-Fe0/PAA system was environmentally friendly. EDTA-Fe0/PAA system exhibited favorable pH applicability, required lesser amounts of Fe0 and PAA, and exhibited resilience against inorganic ions and humic acid. It also performed effectively antibiotic removal performance in natural freshwater environments. In conclusion, this study presents a promising technique for the removal of antibiotics.