研究报告
李文斌,孟昭福,刘泽,吴琼,许绍娥,朱军.两性与两性复配修饰膨润土增强塿土吸附Cr(VI)的研究[J].环境科学学报,2016,36(10):3810-3817
两性与两性复配修饰膨润土增强塿土吸附Cr(VI)的研究
- Enhanced absorption of Cr(VI) on Lou soil by amphoteric and amphoteric-cationic modified bentonite
- 基金项目：国家自然科学基金（No.41271244）；陕西省社会发展攻关项目（No.2013K13-01-05）
- 作者
- 单位
- 李文斌
- 西北农林科技大学资源环境学院, 杨凌 712100
- 孟昭福
- 1. 西北农林科技大学资源环境学院, 杨凌 712100;2. 农业部西北植物营养与农业环境重点实验室, 杨凌 712100
- 刘泽
- 西北农林科技大学资源环境学院, 杨凌 712100
- 吴琼
- 西北农林科技大学资源环境学院, 杨凌 712100
- 许绍娥
- Department of Biological and Agriculture Engineering, University of Arkansas, Fayetteville 72707, US
- 朱军
- Department of Biological and Agriculture Engineering, University of Arkansas, Fayetteville 72707, US
- 摘要：为了证实添加修饰黏土对塿土吸附Cr（VI）的增强作用，分别将2%、5%、8%和10%（质量分数）的200% CEC BS-12（十二烷基二甲基甜菜碱）修饰膨润土（B200B）和100% CEC BS-12+100% CEC DTAB（十二烷基三甲基溴化铵）复配修饰膨润土（B100B/100D）加入到天然塿土，以批处理法研究供试土样对Cr（VI）的等温吸附特征，并对比了pH值、温度和离子强度（I）对Cr（VI）吸附的影响.结果表明：不同B100B/100D塿土（B100B/100D混合塿土）和B200B塿土对Cr（VI）的吸附量分别是CK（塿土）的1.52～4.28和1.99～5.12倍，且等添加比例下B200B塿土对Cr（VI）的吸附量高于B100B/100D塿土.10～30℃范围内，CK、2%B100B/100D和2%B200B塿土对Cr（VI）的吸附呈增温正效应；当修饰土添加比例大于2%时，温度效应由增温正效应向负效应转变.CK对Cr（VI）的吸附量在不同pH值（4～7）处理下差异不显著，而B100B/100D和B200B塿土对Cr（VI）的吸附量均随pH值升高而降低.CK和B100B/100D塿土对Cr（VI）的吸附量均随离子强度（I）的增大而降低，B200B塿土对Cr（VI）的吸附量以I=0.1 mol·L-1时最高，以I=0.5 mol·L-1时最低.B100B/100D和B200B塿土吸附Cr（VI）是自发的物理过程，随修饰土添加比例的增大，吸附表现为焓增、熵减特征.
- Abstract：To examine whether the addition of modified clays can increase the adsorption ability of Cr(VI) on Lou soil,B200B (Bentonite modified by 200% CEC BS-12 (dodecyl dimethyl betaine)) and B100B/100D (Bentonite modified by 100% CEC BS-12 and 100% CEC DTAB (dodecyl trimethyl ammonium Bromide)) were added into Lou soil with the mass fraction of 2%,5%,8% and 10%,respectively.The adsorption characteristics of Cr(VI) by different Lou samples were studied by batch methods.The effects of pH value,temperature and ionic strength (I) on Cr(VI) adsorption were compared.The results indicated that the adsorption capacities of Cr(VI) on B100B/100D Lous (Lou soil mixed with B100B/100D) and B200B Lous increased by 1.99~5.12 and 1.52~4.28 times,respectively,as compared with the one of CK (original Lou soil).With the same adding proportion,B200B Lous showed higher adsorption capacity t of Cr(VI) than B100B/100D Lous.CK,2% B200B Lou and 2% B100B/100D Lou all presented positive temperature effect on Cr(VI) adsorption in the range of 10 to 30℃.When the adding proportion reached 5%,the temperature effect changed from positive to negative.pH had no significant effect on Cr(VI) adsorption by CK in the pH range of 4~7,while increasing pH reduced the adsorption capacities of Cr(VI) by B100B/100D Lous and B200B Lous.Besides,increasing I weakened the adsorption capacities of Cr(VI) by CK and B100B/100D Lous,but the highest and lowest capacities of Cr(VI) adsorption by B200B Lous were obtained at I=0.1 mol·L-1 and I=0.5 mol·L-1,respectively.Cr(VI) adsorption by B100B/100D Lous and B200B Lous was a spontaneous physical process.The enthalpy increased and entropy decreased with the increase of adding proportion.
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