Krishna B S, Mahadevaiah N, Murty D S R, Prakash B S Jai
Department of Chemistry, Bangalore Institute of Technology, KR. Road, Bangalore 560 004, India.
J Colloid Interface Sci. 2004 Mar 15;271(2):270-6. doi: 10.1016/j.jcis.2003.12.002.
Removal of lead ( Pb2+ ) ions from aqueous solution by adsorption onto surfactant-immobilized interlayer species bonded to montmorillonite clay (SIIS-clay) was investigated. Surfactant-immobilized interlayer chromate bound to clay (SIICr-clay) was prepared by treatment of montmorillonite clay with hexadecyltrimethylammonium (HDTMA) bromide followed by chromate adsorption at the intergallery framework of the clay. Experiments were carried out as a function of solution pH, solute concentration, and temperature (5-45 degrees C). The Dubinin-Kaganer-Radushkevich (DKR) model was adopted to describe the single-solute adsorption isotherms. Adsorption energy for lead ions on SIICr-clay computed from the DKR equation shows that a precipitation mechanism was operative. The thermodynamic parameters ( Delta G 0, Delta H 0, and Delta S 0) for lead ion adsorption on SIICr-clay were also determined from the temperature dependence. The kinetics of metal ion adsorption was examined and the first-order rate constant was finally evaluated. Adsorbed lead ions could be recovered completely on leaching with the disodium salt of ethylenediamine tetraacetic acid (EDTA) solution and the adsorbent was found to readsorb lead ions repeatedly after leaching. Thus, surfactant-modified smectite clays offer an effective method for designing a recyclable adsorbent for lead ions.
研究了通过吸附到与蒙脱石粘土结合的表面活性剂固定层间物种（SIIS-粘土）上从水溶液中去除铅（Pb2+）离子的方法。通过用十六烷基三甲基溴化铵（HDTMA）处理蒙脱石粘土，然后在粘土的层间骨架上吸附铬酸盐，制备了与粘土结合的表面活性剂固定层间铬酸盐（SIICr-粘土）。实验作为溶液pH、溶质浓度和温度（5-45摄氏度）的函数进行。采用杜宾宁-卡加内尔-拉杜什凯维奇（DKR）模型描述单溶质吸附等温线。根据DKR方程计算的铅离子在SIICr-粘土上的吸附能表明沉淀机制起作用。还根据温度依赖性确定了铅离子在SIICr-粘土上吸附的热力学参数（ΔG0、ΔH0和ΔS0）。研究了金属离子吸附的动力学，并最终评估了一级速率常数。用乙二胺四乙酸（EDTA）二钠盐溶液浸出时，吸附的铅离子可以完全回收，并且发现吸附剂在浸出后可以反复再吸附铅离子。因此，表面活性剂改性的蒙脱石粘土为设计可回收的铅离子吸附剂提供了一种有效方法。
