De Debasis, Mandal Santi M, Bhattacharya Jayanta, Ram Shanker, Roy Sanat K
Department of Metallurgical and Materials Engineering, Indian Institute of Technology, Kharagpur, W.B., India.
J Environ Sci Health A Tox Hazard Subst Environ Eng. 2009 Feb 1;44(2):155-62. doi: 10.1080/10934520802539756.
Iron oxide nanoparticles (IONPs) can play a significant role in the cycling of heavy metals. Arsenite [As(III)] is highly toxic, mobile, and predominant species in arsenic-contaminated groundwater. IONPs have been synthesized and tested for the removal of As(III) from arsenic contaminated water. In this work, we synthesized IONPs, as a finely divided loose nanopowder, using a chemical method involving a dispersion of the metal cations (Fe3+) through polymer molecules of polyvinyl alcohol (PVA) in an aqueous medium. X-ray diffraction (XRD) analysis confirmed the formation of a single phase rhombohedral crystal structure of R3c space group. Transmission electron microscopic images corroborate the result of IONPs of 45 nm average size and the rhombohedral shape. Selective experiments, conducted with an initial concentration of 0.25 ppm of As(III), have demonstrated the maximum As(III) adsorption capacity (96%) in 2.0 gL(- 1) IONPs in water at pH 4.5-7.5. At room temperature, the adsorption isotherm studies have revealed a better correlation with the Langmuir isotherm than the Freundlich isotherm. Characteristic surface hydrolysis of IONPs as = Fe-OH species has been studied in terms of the vibration bands. The results reveal that the removal of the As(III) species from water is associated with the As(III) adsorption onto the IONPs followed by a surface hydrolysis of the iron species.
氧化铁纳米颗粒（IONPs）在重金属循环中可发挥重要作用。亚砷酸盐[As(III)]毒性极高、具有流动性，且是砷污染地下水中的主要形态。已合成IONPs并测试其从砷污染水中去除As(III)的效果。在本研究中，我们采用化学方法，通过在水介质中使金属阳离子（Fe3+）通过聚乙烯醇（PVA）的聚合物分子分散，合成了作为细分疏松纳米粉末的IONPs。X射线衍射（XRD）分析证实形成了R3c空间群的单相菱面体晶体结构。透射电子显微镜图像证实了平均尺寸为45 nm且呈菱面体形状的IONPs的结果。以初始浓度0.25 ppm的As(III)进行的选择性实验表明，在pH 4.5 - 7.5的水中，2.0 gL(-1)的IONPs对As(III)的最大吸附容量为96%。在室温下，吸附等温线研究表明，与Freundlich等温线相比，与Langmuir等温线的相关性更好。已根据振动带研究了IONPs作为 = Fe-OH物种的特征表面水解。结果表明，从水中去除As(III)物种与As(III)吸附到IONPs上随后铁物种的表面水解有关。
