物理化学学报 >> 2011, Vol. 27 >> Issue (11): 2711-2718.doi: 10.3866/PKU.WHXB20111134

材料物理化学 上一篇    下一篇

纳米Fe@SiO2一步合成及其对Cr(VI)的去除

李勇超, 李铁龙, 王学, 金朝晖   

  1. 南开大学环境科学与工程学院, 环境污染过程与基准教育部重点实验室, 天津 300071
  • 收稿日期:2011-06-17 修回日期:2011-09-08 发布日期:2011-10-27
  • 通讯作者: 金朝晖 E-mail:jinzh@nankai.edu.cn
  • 基金资助:

    国家自然科学基金(40971254, 20907023, 41173102)

One-Step Synthesis of Fe@SiO2 and Its Application in Cr(VI) Removal

LI Yong-Chao, LI Tie-Long, WANG Xue, JIN Zhao-Hui   

  1. College of Environmental Science and Engineering, Nankai University, Key Laboratory of Pollution Processes and Environmental Criteria, Ministry of Education, Tianjin 300071, P. R. China
  • Received:2011-06-17 Revised:2011-09-08 Published:2011-10-27
  • Contact: JIN Zhao-Hui E-mail:jinzh@nankai.edu.cn
  • Supported by:

    The project was supported by the National Natural Science Foundation of China (40971254, 20907023, 41173102 ).

摘要: 利用液相还原与改进的Stöbr 法相结合, 在不使用表面改性剂和氨水的条件下, 通过向原硅酸乙酯(TEOS)和氯化铁混合溶液直接添加硼氢化钾, 一步合成了二氧化硅包覆的纳米铁复合材料(Fe@SiO2). 通过X射线粉末衍射(XRD)仪、能量色散X射线仪(EDAX)、透射电子显微镜(TEM)、紫外-可见(UV-Vis)吸收分光光度计、傅里叶红外(FTIR)光谱仪、X射线光电子能谱仪(XPS)等对所得样品的形貌、结构和组成进行表征. 将制备的Fe@SiO2用于水体中Cr(VI)还原去除并考察了TEOS添加量对其去除能力的影响. 结果表明Fe@SiO2具有清晰的核壳结构, 多孔的SiO2层包裹1-2 个球形纳米铁粒子. 纳米铁粒径主要分布在20-30 nm之间, 随着TEOS投加量的增加, SiO2层变厚, 纳米铁核具有更好的分散性. 与未包覆型纳米铁相比, Fe@SiO2对Cr(VI)的去除能力显著提高. TEOS投加量为0.1 mL所制备的Fe@SiO2对Cr(VI)去除能力(以Fe 的质量计算)达到最大, 为466.67 mg·g-1, 而未包覆型纳米铁仅为76.35 mg·g-1.

关键词: 二氧化硅壳层, 纳米铁, 一步合成, Cr(VI), 还原

Abstract: Without using aqueous ammonia and a surface modifier, a facile one-step method was developed to fabricate Fe nanoparticles coated with a SiO2 shell (Fe@SiO2) by a modified Stöber method combined with an aqueous reduction method. The Fe@SiO2 was prepared by directly adding potassium borohydride to a mixed solution of tetraethylorthosilicate (TEOS) and anhydrous ferric chloride. The structure and morphology of the as-synthesized powders were investigated by X-ray powder diffraction (XRD), energy dispersion analysis of X-ray (EDAX), transmission electron microscopy (TEM), ultraviolet-visible (UV-Vis) absorption spectroscopy, Fourier-transform infrared (FTIR) spectrometry and X-ray photoelectron spectroscopy (XPS). The feasibility of using the prepared Fe@SiO2 for the reductive immobilization of Cr(VI) in water was studied. The influence of TEOS addition on Cr(VI) removal by Fe@SiO2 was investigated. The results showed that the prepared Fe@SiO2 had a distinct core-shell structure. One or two Fe nanoparticles (20-30 nm in diameter) were homogeneously coated by a porous SiO2 shell. With an increase in the amount of added TEOS the Fe nanoparticles had better dispersion and the thickness of the SiO2 coating increased gradually. Compared with uncoated Fe nanoparticles, Cr(VI) removal by Fe@SiO2 increased greatly. At a TEOS dosage of 0.1 mL the removal ability of the prepared Fe@SiO2 was the highest. The highest removal ability of Fe@SiO2 was 466.67 mg·g-1 and it was only 76.35 mg·g-1 for uncoated Fe nanoparticles.

Key words: SiO2 shell, Fe nanoparticles, One-step synthesis, Hexavalent chromium, Reduction

MSC2000: 

  • O647