The magnetically recoverable C-ZnFe2O4 as a microwave absorption catalyst for the degradation of norfloxacin by persulfate: Mechanism, degradation pathway, toxicity, and stability

Abstract

Norfloxacin (NOR), a widely used fluoroquinolone antibiotic, has been a focus of attention in recent years due to its adverse effect on human beings and aquatic ecosystems. Magnetic C-ZnFe2O4 (C-ZFO) composite was fabricated by a one-step hydrothermal method and characterized via SEM, TEM, XRD, XPS, VSM. Under given conditions:[NOR] = 5 mg/L, [persulfate (PS)] = 0.25 mM, [pH]0 = 6.7, [C-ZFO] = 1.5 g/L, MW = 400 W, T = 70 ℃, the degradation of NOR reached 86.2% in 40 min, and the highest TOC removal ratio reached 69.6%. The presence of active species (SO4·−,·O2−, HO·, h+) was monitored in C-ZFO activated persulfate under microwave irradiation system (MW-C-ZFO/PS) through radical scavenger study. Meanwhile, intermediate products of NOR and five possible degradation pathways were identified using HPLC-MS. Moreover, the toxicity of NOR intermediates was analyzed by the Vibrio fischeri to evaluate the health risk of the treated water. Overall, microwave irradiation is an efficient technology for degrading NOR in environmental remediation.