Lin Su-Hsia, Chen Chia-Nan, Juang Ruey-Shin
Department of Chemical and Materials Engineering, Nanya Institute of Technology, Chung-Li, Taiwan.
J Environ Manage. 2009 Apr;90(5):1950-5. doi: 10.1016/j.jenvman.2008.12.013. Epub 2009 Jan 20.
Chromium(VI)-containing sorbents in the form of sludge or solid residue from treatment processes are often landfilled or used as fill materials, therefore the long-term stability of metal binding is important. The reduction of Cr(VI)-Cr(III) through heat treatment may be a useful detoxification method. After heating at 500, 900, 1000, and 1100 degrees C for 4h, the transformation of chemical states of chromium on 105 degrees C-dried, 7.9% Cr(VI)-doped TiO(2) powders was studied on the basis of surface area measurements, scanning electron microscopy (SEM) images, X-ray diffraction (XRD), and extended X-ray absorption fine structure (EXAFS) spectra. It was shown that Cr(VI) was reduced to Cr(III) in the Cr(VI)-doped samples after heating within 500-900 degrees C. The present results also suggested that the chromium octahedral was bridged to the titanium tetrahedral and was incorporated in TiO(2) minerals formed after 1000 degrees C treatment.
来自处理过程的污泥或固体残渣形式的含铬（VI）吸附剂通常被填埋或用作填充材料，因此金属结合的长期稳定性很重要。通过热处理将Cr（VI）还原为Cr（III）可能是一种有用的解毒方法。在500、900、1000和1100摄氏度下加热4小时后，基于表面积测量、扫描电子显微镜（SEM）图像、X射线衍射（XRD）和扩展X射线吸收精细结构（EXAFS）光谱，研究了在105摄氏度干燥、掺杂7.9% Cr（VI）的TiO₂粉末上铬的化学状态转变。结果表明，在500-900摄氏度范围内加热后，掺杂Cr（VI）的样品中Cr（VI）被还原为Cr（III）。目前的结果还表明，铬八面体与钛四面体桥连，并在1000摄氏度处理后形成的TiO₂矿物中结合。
