Degradation of Oxytetracycline by Zero-Valent Iron Activated Periodate: Efficiency Optimization, Performance Improvement, Reaction Mechanisms, and Application Analysis

The increasing contamination of aquatic environments by antibiotics calls for efficient, economical, and environmentally sustainable remediation technologies. This study presents a zero-valent iron (ZVI)-activated periodate (IO 4 − ) advanced oxidation system for the degradation of oxytetracycline (OTC) in water. Under optimized conditions (pH = 3, ZVI = 1.64 g/L, IO 4 −  = 1.97 mM), the ZVI/IO 4 − system achieved 81.16% OTC removal. Notably, coupling with UV irradiation enabled complete OTC degradation within 50 min, demonstrating substantial enhancement over the standalone system. Mechanistic investigations revealed that IO 3 • , 1 O 2 , and O 2 •− were the dominant reactive species, and three degradation pathways were proposed based on LC–MS analysis. The system exhibited excellent performance in real water matrices, achieving 78.0% and 71.9% OTC removal in tap water and lake water, respectively, along with strong tolerance to coexisting ions and humic acid. Importantly, the ZVI catalyst retained 96.4% of its initial activity after five consecutive cycles, significantly reducing operational costs and secondary pollution risks. This work provides an efficient, stable, and cost-effective treatment strategy for antibiotic-contaminated water, holding strong promise for practical engineering applications.