Fe3O4-nZVI类Fenton法降解水中磺胺甲恶唑

采用共沉淀和液相还原两步法制得四氧化三铁负载纳米零价铁(Fe₃O₄-nZVI),将其作为类Fenton反应的催化剂用于水中磺胺甲恶唑(SMX)的降解.通过批实验法研究了H₂O₂浓度、Fe₃O₄-nZVI投加量、pH值、SMX初始浓度、反应温度等因素对SMX降解的影响.SEM、EDS、XRD和XPS表征结果表明,制备的Fe₃O₄-nZVI为纳米级磁性复合材料.批实验结果表明,在一定实验条件范围内,提高H₂O₂浓度、Fe₃O₄-nZVI投加量和反应温度,以及降低体系pH值,均可提高SMX的降解率.动力学拟合参数表明,SMX的类Fenton催化降解符合拟一级动力学模型.在25℃时,当H₂O₂浓度为10mmol/L、Fe₃O₄-nZVI投加量为0.8g/L、pH=3、SMX初始浓度为10mg/L,SMX在180min时的降解率为99.61%.用VSM测得Fe₃O₄-nZVI的饱和磁化强度为105.52emu/g,表明其易于磁回收.重复利用实验表明,Fe₃O₄-nZVI具有较好的反应活性和稳定性.自由基淬灭实验表明,·OH的氧化作用是SMX降解的主要机理.

Degradation of sulfamethoxazole in water by Fenton-like method using Fe3O4-nZVI

Fe₃O₄-nZVI was prepared by co-precipitation and liquid phase reduction method. The obtained Fe₃O₄-nZVI was used as catalyst of Fenton-like reaction to degrade sulfamethoxazole (SMX) in water. The effects of H₂O₂ concentration, Fe₃O₄-nZVI dosage, pH of solution, SMX concentration and temperature on SMX degradation were investigated. The charactering results of SEM, EDS, XRD and XPS showed that the magnetic composite material with nanometer size was successfully prepared. The batch experimental results showed that the degradation rate of SMX in Fenton-like system increased as the increase of H₂O₂ concentration, Fe₃O₄-nZVI dosage and temperature, and decrease of pH in studied experimental ranges. The fitting parameters of kinetic showed that SMX degradation fitted the pseudo-first-order kinetic model. Under the given conditions, which were H₂O₂ 10mmol/L, Fe₃O₄-nZVI 0.8g/L, pH=3, SMX 10mg/L, and reaction temperature 25℃, the degradation rate of SMX was 99.61% at 180min. The magnetization of Fe₃O₄-nZVI was 105.52emu/g, indicating it was easy for magnetic recycle. Reused experiments showed that Fe₃O₄-nZVI had excellent reactivity and stability. Free radical quenching experiments showed that the oxidation of ·OH played a key role on degrading SMX in water.