Ofloxacin (OFL) may cause potential ecological risks since it cannot be effectively removed by conventional biological degradation. The advanced oxidation process is an efficient approach for antibiotic removal. Herein, a heterogeneous system for hydrogen peroxide (H2O2) activation by nanoscale zero-valent iron (nZVI) supported on powdered activated carbon (PAC) composite (nZVI@PAC) was proposed to proceed with the removal of OFL. Typically, OFL (25 mg/L) can be removed up to 94.7 % within 60 min ([H2O2] = 10 mM, [nZVI@PAC] = 125 mg/L, pH = 6, T = 318 K). The effects of initial OFL concentration, pH, nZVI@PAC dosage, H2O2 concentration, and different actual water matrices were examined to explore the application conditions and resistance of the nZVI@PAC/H2O2 system. Meanwhile, the quenching experiment, PMSO probe experiment, and EPR results showed •OH and FeIVO were the dominant reactive species in the system. Moreover, a sensible mechanism for OFL removal was proposed that nZVI@PAC aggregates OFL on its surface by adsorption, and then persistent free radicals (PFRs) and nZVI on the PAC degrade OFL by activating H2O2 to produce •OH and FeIVO. Furthermore, the effect of micro-electronic iron-carbon composite was proved by electrochemical experiments and density functional theory (DFT) calculations. Moreover, the degradation pathway of OFL in the nZVI@PAC/H2O2 system and the toxicity assessment of intermediates were also given. Meanwhile, sequential runs and continuous flow column experiments showed nZVI@PAC/H2O2 system had high stability. This work provides an innovative strategy of an advanced oxidation process based on heterogeneous reactions for organic contaminants removal using metal–carbon catalysts.

中文翻译：

---

氧氟沙星在水和多孔介质中的降解：微电解铁碳复合材料通过过氧化氢活化产生的协同效应


氧氟沙星（OFL）由于无法通过常规生物降解有效去除，可能会造成潜在的生态风险。高级氧化工艺是去除抗生素的有效方法。在此，提出了一种通过粉状活性炭（PAC）复合材料（nZVI@PAC）负载的纳米级零价铁（nZVI）活化过氧化氢（H2O2）的非均相系统，以去除OFL。通常，OFL (25 mg/L) 可在 60 分钟内去除高达 94.7%（[H2O2] = 10 mM，[nZVI@PAC] = 125 mg/L，pH = 6，T = 318 K）。考察了OFL初始浓度、pH、nZVI@PAC用量、H2O2浓度和不同实际水基质的影响，以探讨nZVI@PAC/H2O2系统的应用条件和耐受性。同时，猝灭实验、PMSO探针实验和EPR结果表明·OH和FeIVO是体系中的主要反应物种。此外，提出了一种去除OFL的合理机制，即nZVI@PAC通过吸附在其表面聚集OFL，然后PAC上的持久性自由基（PFR）和nZVI通过激活H2O2产生·OH和FeIVO来降解OFL。此外，通过电化学实验和密度泛函理论（DFT）计算证明了微电子铁碳复合材料的效果。此外，还给出了OFL在nZVI@PAC/H2O2体系中的降解途径以及中间体的毒性评估。同时，顺序运行和连续流柱实验表明nZVI@PAC/H2O2体系具有较高的稳定性。这项工作提供了一种基于多相反应的高级氧化工艺的创新策略，用于使用金属碳催化剂去除有机污染物。