Mohapatra Debasish, Mishra Debaraj, Chaudhury G Roy, Das R P
Minerals and Materials Processing Division, Korea Institute of Geoscience and Mineral Resources (KIGAM), Daejeon 305 350, Korea.
J Environ Sci Health A Tox Hazard Subst Environ Eng. 2007 Mar;42(4):463-9. doi: 10.1080/10934520601187666.
The present work investigates the adsorptive behavior of As(V) ions with kaolinite, montmorillonite and illite in aqueous medium as a function of As(V) concentration, pH, contact time and temperature. As(V) adsorption on studied clays were pH dependent and maximum adsorption were achieved in the pH range 2.0-5.0. The adsorption data gave good fits with Langmuir isotherm and yielded Langmuir monolayer capacity of 0.86, 0.64 and 0.52 mg As(V) /g of kaolinite, montmorillonite and illite, respectively. An increase in adsorption temperature resulted in a decrease in the amount of As(V) adsorbed. The results of leaching study showed that, kaolinite was very active clay constituent regarding both As(V) adsorption and mobility. The electrokinetic behavior of both the kaolinite and montmorillonite were modified in the presence of As(V). The shift in isoelectric point indicated that adsorption involves inner sphere surface complexation and strong specific ion adsorption. Kaolinite was successfully tested as an adsorbent for the removal of arsenic from two contaminated groundwater samples containing arsenic in the range 1.36-1.41 mg/L.
本研究考察了高岭土、蒙脱石和伊利石在水介质中对五价砷离子的吸附行为,该行为是五价砷浓度、pH值、接触时间和温度的函数。五价砷在所研究黏土上的吸附取决于pH值,在pH值为2.0至5.0的范围内实现最大吸附量。吸附数据与朗缪尔等温线拟合良好,高岭土、蒙脱石和伊利石的朗缪尔单层吸附容量分别为0.86、0.64和0.52 mg五价砷/克。吸附温度升高导致五价砷吸附量减少。浸出研究结果表明,高岭土在五价砷吸附和迁移方面是非常活跃的黏土成分。在五价砷存在下,高岭土和蒙脱石的电动行为均发生改变。等电点的变化表明吸附涉及内球表面络合和强特异性离子吸附。高岭土成功地被测试为一种吸附剂,用于从两个含砷量在1.36至1.41 mg/L范围内的受污染地下水样品中去除砷。