污染控制技术及原理
陆海军,栾茂田,张金利,于永鲜.垃圾填埋场衬垫对Cr(Ⅵ)和Zn(Ⅱ)吸附的动力学研究[J].环境科学学报,2009,29(1):156-162
垃圾填埋场衬垫对Cr(Ⅵ)和Zn(Ⅱ)吸附的动力学研究
- Kinetic study on the adsorption of Cr(Ⅵ) and Zn(Ⅱ) onto landfill liners
- 基金项目：国家自然科学基金项目(No.50639010)
- 作者
- 单位
- 陆海军
- 大连理工大学岩土工程研究所, 大连 116085
- 栾茂田
- 大连理工大学岩土工程研究所, 大连 116085
- 张金利
- 大连理工大学岩土工程研究所, 大连 116085
- 于永鲜
- 大连理工大学化学系, 大连 116085
- 摘要：通过静态平衡吸附试验对垃圾填埋场衬垫土壤材料对Cr(Ⅵ)和Zn(Ⅱ)的吸附进行了观察.在试验中考察了溶液的初始浓度、pH值和溶液的温度对吸附的影响,通过动力学实验确定了动力学参数,并探讨了天然黏土材料对重金属Cr(Ⅵ)和Zn(Ⅱ)的吸附机理.结果显示,黏土对重金属的吸附过程可以通过伪二阶动力模式来描述.根据对lnk2与1/T线形图斜率的计算,可以确定Cr(Ⅵ)和Zn(Ⅱ)的活化能(Ea)分别为22.7 kJ·mol-1和26.88 kJ·mol-1.活化能的计算结果说明,温度的升高能促进黏土材料对Cr(Ⅵ)和Zn(Ⅱ)的吸附,同时也表明吸附很可能是一个化学吸附.热力学参数(ΔHsup>0,ΔS0,ΔG0)值可以通过图lgKD与1/T的斜率与截距来计算.热力学参数值的结果表明,天然黏土材料对Cr(Ⅵ)和Zn(Ⅱ)的吸附是吸热反应.
- Abstract：Sorption of Cr(Ⅵ) and Zn(Ⅱ) to the natural clay used as the liner-soil material of a solid waste landfill was investigated by batch tests.Key physico-chemical parameters such as the initial concentration of solution,pH,and the temperature of the solution were investigated.In order to understand the adsorption mechanism,the kinetic parameters of adsorption of Cr(Ⅵ) and Zn(Ⅱ) onto the natural clay were determined.The pseudo-second order kinetic model best described the adsorption of Cr(Ⅵ) and Zn(Ⅱ) onto the natural clay.The activation energy(Ea) values for Cr(Ⅵ) and Zn(Ⅱ) were found to be 22.7 kJ·mol-1 and 26.88 kJ·mol-1 according to the slopes of the plots of lnk2 against 1/T.The Ea values suggest that the rise of the solution temperature favors adsorption of Cr(Ⅵ) and Zn(Ⅱ) onto the clay,and the adsorption process probably occurs by chemical adsorption.The thermodynamic parameters(ΔH0,ΔS0,ΔG0) values were calculated from the slope and the intercept of the linear plot of lgKD versus 1/T.The results indicate that the adsorption of Cr(Ⅵ) and Zn(Ⅱ) onto the natural clay is endothermic.
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