丙酮冲洗法提高纳米零价铁抗氧化性能

纳米零价铁(nanoscale zero valent iron,nZVI)具有还原能力强、便于回收等优势,是目前广泛应用于地下水污染治理的一种活性纳米材料.然而,nZVI易被空气氧化失活及其储存难等问题严重地限制了其应用.为增强nZVI抗氧化能力,本文首次采用丙酮(acetone)对新制备的nZVI样品进行简单冲洗,并以水洗(water)作为对照,分别得到nZVIA和nZVIW样品.采用扫描电镜(SEM)、X-射线衍射(XRD)、X-射线光电子能谱(XPS)、傅里叶变换红外吸收光谱(FT-IR)和热重分析(TGA)等技术对样品的物理结构、表面性质进行了表征.结果发现,相较于表面粗糙、有大量氧化物存在的nZVIW,nZVIA为表面光滑球形,说明经丙酮简单冲洗能有效提高Fe0纯度.通过对在空气中持续暴露15 d后的样品进行XRD测试及其对甲基橙(MO)降解动力学实验,发现nZVIA具有优异的抗氧化能力,这源于通过配位吸附在nZVIA表面的丙酮分子起到的阻隔作用.此外,通过测试两种样品对三氯乙酸(trichloroacetic acid,TCA)脱氯实验,发现nZVIA对TCA的降解速率是nZVIW的3.37倍,对TCA具有更快的脱氯能力.本研究为制备高活性且兼有抗氧化能力的nZVI提供了一种十分简单的改性方法.

Anti-oxidation ability of nanoscale zero valent iron viaacetone flushing method

Thanks to the advantages in high-reductive capacity and recovery available,nanoscale Zero Valent Iron(nZVI)has been widely used as an active nanomaterial in the decontamination of groundwater.However,nZVI is easily oxidized and deactivated by air and difficult to store,which significantly limits its application.In order to improve the anti-oxidation ability of nZVI,acetone was firstly applied to rinse nZVI particles to obtain nZVIW,and water was used as the control regent to prepare nZVIA.The structure and properties of the two samples were characterized by scanning electron microscope(SEM),X-ray diffraction(XRD),X-ray photoelectron spectroscopy(XPS),infrared Fourier absorption spectroscopy(FT-IR)and thermogravimetric analysis(TGA).Compared to the presence of a large amount of oxides on the rough surface of nZVIW,nZVIA had spherical structure with smooth surface,indicating that simple washing of acetone can effectively improve the purity of Fe0.According to the XRD analysis and degradation experiment of methyl orange(MO)of samples that suffered 15 days of continuous exposure to air,nZVIA displayed excellent antioxidant capacity,which was mainly due to the barrier effect of acetone molecules adsorbed on the surface of nZVIA through coordination.Furthermore,the dechlorination experiment of Trichloroacetic Acid(TCA)showed that the degradation rate of TCA by nZVIA is 3.37 times higher than that of nZVIW and nZVIA had faster dechlorination rate of TCA.This study provided a very simple modification method for the preparation of nZVI with high activity and antioxidant capacity.