Stabilization of heavy metals in soil using two organo-bentonites
Stabilization of heavy metals in soil using two organo-bentonites
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使用两种有机膨润土稳定土壤中的重金属
DOI：
10.1016/j.chemosphere.2017.06.040
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发表时间：
2017-10-01
期刊：
影响因子：
8.8
通讯作者：
Lu, Jinlong
中科院分区：
文献类型：
--
作者：
Yu, Kai;Xu, Jian;Lu, Jinlong
研究了四甲基铵(TMA)和十二烷基三甲基铵(DTMA)改性膨润土(T-Bents和D-Bents)对土壤中铜、锌、镉、汞、铬和砷的稳定作用。采用毒性特征淋洗法(TCLP)对土壤处理后土壤中金属的迁移率进行了量化。在膨润土的阳离子交换容量分别为40%、80%、120%、160%和200%时，测定了改性膨润土的BET比表面积、层间距和Zeta电位等结构参数。结果表明，有机膨润土的性质随改性剂的种类和浓度的不同而发生根本的变化。T-Bents和D-Bents对多种金属表现出不同的固定化效果。结合有机膨润土的特点，铜、锌、镉的主要作用机理是阳离子交换，汞是通过物理吸附和分配作用进行的，铬和砷分别是通过专性吸附和静电吸引作用进行的。本研究为优化有机粘土合成工艺，选择合适的改良剂修复重金属污染土壤提供了操作和机理依据。(C)2017爱思唯尔有限公司。保留所有权利。
Stabilization of Cu, Zn, Cd, Hg, Cr and As in soil using tetramethylammonium (TMA) and dodecyltrimethylammonium (DTMA) modified bentonites (T-Bents and D-Bents) as amendments was investigated. Toxicity characteristic leaching procedure (TCLP) was used to quantify the metal mobility after soil treatment. The structural parameters of modified bentonites, including the BET surface area, basal spacing and zeta potential were obtained as a function of the TMA and DTMA loading at 40, 80, 120, 160 and 200% of the bentonite's cation exchange capacity, respectively. The results indicated that the characteristics of the organo-bentonites fundamentally varied depending on the species and concentration of modifiers loaded on bentonite. T-Bents and D-Bents manifested distinct immobilization effectiveness towards various metals. In association with the organo-bentonite characteristics, the main interactive mechanisms for Cu, Zn and Cd proceeded via cation exchange, Hg proceeded via physical adsorption and partitioning, Cr and As proceeded via specific adsorption and electrostatic attraction, respectively. This study provided operational and mechanistic basis for optimizing the organic clay synthesis and selecting as the appropriate amendment for remediation of heavy metal contaminated soils. (C) 2017 Elsevier Ltd. All rights reserved.