Chemical and Environmental Systems Modeling Research Group, Institute of Fundamental Studies, Hanthana Road, Kandy, 20000, Sri Lanka.
Environ Sci Pollut Res Int. 2014;21(11):7075-87. doi: 10.1007/s11356-014-2625-1. Epub 2014 Feb 19.
The use of nanoparticulate zero valent iron (NZVI) in the treatment of inorganic contaminants in landfill leachate and polluted plumes has been the subject of many studies, especially in temperate, developed countries. However, NZVI's potential for reduction of chemical oxygen demand (COD) and treatment of metal ion mixtures has not been explored in detail. We investigated the efficiency of NZVI synthesized in the presence of starch, mercaptoacetic, mercaptosuccinic, or mercaptopropenoic acid for the reduction of COD, nutrients, and metal ions from landfill leachate in tropical Sri Lanka. Synthesized NZVI were characterized with X-ray diffraction (XRD), transmission electron microscopy, X-ray photoelectron spectroscopy, scanning electron microscopy (SEM), thermal gravimetric analysis, Fourier transform infrared spectroscopy (FTIR) and Brunauer-Emmett-Teller. Of the samples tested, Starch-NZVI (S-NZVI) and mercaptoacetic-NZVI (MA-NZVI) performed well for treatment both COD and metal mixture. The removal percentages for COD, nitrate-nitrogen, and phosphate from S-NZVI were 50, 88, and 99 %, respectively. Heavy metal removal was higher in S-NZVI (>95 %) than others. MA-NZVI, its oxidation products, and functional groups of its coating showed the maximum removal amounts for both Cu (56.27 mg g(-1)) and Zn (28.38 mg g(-1)). All mercapto-NZVI showed well-stabilized nature under FTIR and XRD investigations. Therefore, we suggest mercapto acids as better agents to enhance the air stability for NZVI since chemically bonded thiol and carbonyl groups actively participation for stabilization process.
在处理垃圾渗滤液和污染羽流中的无机污染物方面，纳米零价铁（NZVI）的应用已经成为许多研究的主题，尤其是在温带发达国家。然而，NZVI 降低化学需氧量（COD）和处理金属离子混合物的潜力尚未得到详细研究。我们研究了在淀粉、巯基乙酸、巯基丁二酸或巯基丙酸存在下合成的 NZVI 用于还原热带斯里兰卡垃圾渗滤液中的 COD、营养物质和金属离子的效率。合成的 NZVI 用 X 射线衍射（XRD）、透射电子显微镜、X 射线光电子能谱、扫描电子显微镜（SEM）、热重分析、傅里叶变换红外光谱（FTIR）和 Brunauer-Emmett-Teller 进行了表征。在所测试的样品中，淀粉-NZVI（S-NZVI）和巯基乙酸-NZVI（MA-NZVI）在处理 COD 和金属混合物方面表现良好。S-NZVI 对 COD、硝酸盐氮和磷酸盐的去除率分别为 50%、88%和 99%。S-NZVI 对重金属的去除率高于其他样品（>95%）。MA-NZVI、其氧化产物及其涂层的官能团对 Cu（56.27 mg g(-1)) 和 Zn（28.38 mg g(-1)) 的去除量最大。所有巯基 NZVI 在 FTIR 和 XRD 研究中均表现出良好的稳定性。因此，我们建议使用巯基酸作为增强 NZVI 空气稳定性的更好试剂，因为化学结合的硫醇和羰基基团积极参与稳定过程。
