Department of Environmental Engineering and Management, Chaoyang University of Technology, Taichung County, Taiwan, ROC.
Environ Technol. 2011 May-Jun;32(7-8):879-89. doi: 10.1080/09593330.2010.517218.
Acid washing is a common method for soil remediation, but is not always efficient for chromium-contaminated soil. Both soil particle size and the forms of chromium existing in the soil affect the efficiency of soil washing. Laboratory batch and column dissolution experiments were conducted to determine the efficiencies of citric and hydrochloric acids as agents to extract chromium from soils contaminated with chromium. The effects of soil particle size and chromium fractionation on Cr leaching were also investigated. About 90% of chromium in the studied soil existed either in residual form or bound to iron and manganese oxides, and Cr fraction distributions were similar for all soil particle sizes. Almost all exchangeable and carbonate-bound chromium was removed by washing once with 0.5 M HCl, whereas organic chromium was more effectively removed by washing with citric acid rather than with HCl solution of the same concentration. For chromium fractions that were either bound to Fe-Mn oxides or existed as residual forms, the efficiencies of acid washing were usually 20% or less, except for 0.5 M HCl solution, which had much higher efficiencies. Separation of the soil sample by particle size before the separate washing of the soil fractions had little improvement on the chromium removal.
酸洗是一种常见的土壤修复方法，但对于铬污染土壤并不总是有效。土壤颗粒大小和土壤中存在的铬的形态都会影响土壤洗涤的效率。进行了实验室批量和柱溶出实验，以确定柠檬酸和盐酸作为从铬污染土壤中提取铬的试剂的效率。还研究了土壤颗粒大小和铬分馏对 Cr 浸出的影响。在所研究的土壤中，约 90%的铬以残渣形式或与铁和锰氧化物结合存在，并且所有土壤颗粒大小的 Cr 分馏分布相似。用 0.5 M HCl 洗涤一次即可去除几乎所有的可交换和碳酸盐结合的铬，而柠檬酸洗涤比相同浓度的 HCl 溶液更有效地去除有机铬。对于与 Fe-Mn 氧化物结合或以残渣形式存在的铬分馏，酸洗效率通常低于 20%，但 0.5 M HCl 溶液除外，其效率要高得多。在分别洗涤土壤分馏物之前，通过颗粒大小对土壤样品进行分离对铬的去除几乎没有改善。
