研究报告
陈云,于永鲜,张金利,石文平.铁氧化物改性黏土对Cr(Ⅵ)的吸附性能研究[J].环境科学学报,2011,31(5):905-911
铁氧化物改性黏土对Cr(Ⅵ)的吸附性能研究
- Adsorption of Cr(Ⅵ) by iron oxide-modified clay
- 基金项目：国家自然科学基金项目(No.50679015)
- 作者
- 单位
- 陈云
- 大连理工大学化学学院, 大连 116085
- 于永鲜
- 大连理工大学化学学院, 大连 116085
- 张金利
- 大连理工大学土木工程学院, 大连 116085
- 石文平
- 大连理工大学化学学院, 大连 116085
- 摘要：利用铁氧化物对大连地区黏土进行包覆改性,并采用静态吸附法对该改性黏土吸附Cr(Ⅵ)的特性进行了研究,同时考虑了反应时间、pH、溶液初始浓度、温度对吸附的影响.实验结果表明,整个吸附过程基本在3h内完成,改性黏土对Cr(Ⅵ)的吸附量随溶液初始pH的增大而明显减小,随着溶液初始浓度和温度的增大而增大.同时,在初始pH为3.0的条件下,研究了改性黏土吸附Cr(Ⅵ)的动力学和热力学特性.结果表明,改性黏土对Cr(Ⅵ)吸附能较好地用准二级动力学方程和Langmuir等温式描述.由Langmuir等温式计算得出,在293K、初始pH为3.0条件下的单层饱和吸附量为12.91mg·g-1.实验确定了改性黏土吸附Cr(Ⅵ)的热力学参数,结果表明,该吸附过程是一个吸热的自发过程.与原土的对比实验表明,改性黏土对Cr(Ⅵ)的吸附能力大大增强.
- Abstract：Clay in Dalian coated with iron oxides was prepared in this study.The prepared modified clay was used for the removal of Cr(Ⅵ) from aqueous solution.The effect of contact time,pH,solute concentration and temperature on the adsorption of Cr(Ⅵ) by the modified clay were investigated.The results indicated that the high adsorption capacity can be achieved in 3h of equilibration time.The adsorption of Cr(Ⅵ) by modified clay increased with increasing initial concentration of Cr(Ⅵ) and temperature,but decreased significantly with increasing pH.At an optimum pHof 3.0,the adsorption kinetics and isotherms can be best fitted with the pseudo-second order kinetics model and the Langmuir model,respectively.The maximum adsorption capacity of the modified clay calculated by Langmuir model was found to be 12.91 mg·g-1 at 293 K.The thermodynamic parameters revealed that the adsorption of Cr(Ⅵ) by modified clay was a spontaneous and endothermic process.The experimental results indicated that the adsorption capacity of clay can be enhanced greatly by coating with iron oxides.
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