| HDTMA改性蒙脱土对土壤Cr(Ⅵ)的吸附稳定化研究 |
| 摘要点击 2466 全文点击 1248 投稿时间：2015-07-17 修订日期：2015-10-20 |
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| 中文关键词 有机蒙脱土 土壤 铬 吸附 稳定化 |
| 英文关键词 organo-montmorillonite soil chromium adsorption stabilization |
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| 中文摘要 |
| 以钠基蒙脱土为原料,十六烷基三甲基溴化铵(HDTMA)为改性剂,制备了系列有机蒙脱土改性材料,并将其用于Cr(Ⅵ) 污染土壤的稳定化处理研究. 红外光谱、X射线粉末衍射、扫描电镜、氮气吸附脱附、阳离子交换量以及电动电位等表征结果表明,随着HDTMA投加量的增加,蒙脱土层间距从1.25 nm增加到2.13 nm,表面粗糙度下降,比表面积从38.91 m2 ·g-1降低到0.42 m2 ·g-1,可交换的阳离子数量从62 cmol ·kg-1降低到9.9 cmol ·kg-1,且表面电性由-29.1 mV升高到5.59 mV. 毒性浸出实验结果表明, 材料的有效性与土壤初始Cr(Ⅵ)浓度、蒙脱土的投加量、养护时间以及HDTMA的改性量均有关. 随着HDTMA改性量的增加,有机改性蒙脱土对Cr(Ⅵ)的物理吸附作用下降而对污染物的静电作用增强,静电吸附作用是改性蒙脱土对土壤Cr(Ⅵ)的稳定化效果增强的主要原因. |
| 英文摘要 |
| A series of organo-montomorillonites were prepared using Na-montomorillonite and hexadecyl trimethyl ammonium bromide (HDTMA). The organo-montomorillonites were then investigated for the remediation of Cr(Ⅵ) contaminated soils. FT-IR, XRD, SEM and N2-BET, CEC, Zeta potential measurement were conducted to understand the structural changes of montmorillonites as different amounts of HDTMAs were added as modifier. The characterization results indicated that the clay interlayer spacing distance increased from 1.25 nm to 2.13 nm, the clay surface roughness decreased, the clay surface area reduced from 38.91 m2 ·g-1 to 0.42 m2 ·g-1, the clay exchangeable cation amount reduced from 62 cmol ·kg-1 to 9.9 cmol ·kg-1 and the clay surface charge changed from -29.1 mV to 5.59 mV as the dosage of HDTMA in montmorillonite was increased. The TCLP (toxicity characteristic leaching procedure) was used to evaluate the leachate toxicity of Cr(Ⅵ). The effects of the initial soil Cr(Ⅵ) concentration, montmorillonites dosage, reaction time and HDTMA modification amount were investigated, respectively. The results revealed that modification of montmorillonites would manifest an attenuated physical adsorptive effect and an enhanced electrostatic adsorptive effect on Cr(Ⅵ), suggesting electrostatic effect was the major force that resulted in improved Cr(Ⅵ) adsorption onto HDTMA modified montmorillonites. |
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