文章摘要
谢婷,李文斌,孟昭福,路浩源,任爽,YEK Sambath.BS-12+DTAB复配修饰膨润土吸附Cr(Ⅵ)和Cd2+的研究[J].农业环境科学学报,2017,36(9):1778-1786.
BS-12+DTAB复配修饰膨润土吸附Cr(Ⅵ)和Cd2+的研究
Studies on Cr(Ⅵ) and Cd2+ adsorption onto bentonite modified by a BS-12+DTAB complex
投稿时间:2017-03-06  
DOI:10.11654/jaes.2017-0279
中文关键词: 膨润土  复配修饰  吸附  Cr(Ⅵ)  Cd2+
英文关键词: bentonite  complex modification  adsorption  Cr(Ⅵ)  Cd2+
基金项目:国家自然科学基金项目(41271244);陕西省重点研发计划项目(2017SF-385)
作者单位E-mail
谢婷 西北农林科技大学资源环境学院, 陕西 杨凌 712100  
李文斌 西华师范大学环境科学与工程学院, 四川 南充 637009  
孟昭福 西北农林科技大学资源环境学院, 陕西 杨凌 712100
农业部西北植物营养与农业环境重点实验室, 陕西 杨凌 712100 
zfmeng1996@263.net 
路浩源 西北农林科技大学资源环境学院, 陕西 杨凌 712100  
任爽 西北农林科技大学资源环境学院, 陕西 杨凌 712100  
YEK Sambath 西北农林科技大学资源环境学院, 陕西 杨凌 712100  
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中文摘要:
      为了探究和比较两性+阳离子复配修饰膨润土对不同类型重金属离子[Cr(Ⅵ)和Cd2+]的吸附效应及影响机制,采用阳离子型表面修饰剂十二烷基三甲基溴化铵(DTAB或DT)复配修饰两性表面修饰剂十二烷基二甲基甜菜碱(BS-12或BS)修饰膨润土,批处理法研究各复配修饰土样对Cr(Ⅵ)和Cd2+的等温吸附的异同,并对比温度、pH值和离子强度对吸附的影响。结果表明:各复配修饰膨润土对Cr(Ⅵ)和Cd2+的吸附等温线均符合Langmuir模型。供试土样对Cr(Ⅵ)的平衡吸附量呈现BS+150DT(150% CEC的DTAB复配修饰膨润土)> BS+100DT > BS+50DT > BS+25DT > BS > CK(膨润土)的趋势,且最大吸附量(qm)为205.67 mmol·kg-1(BS+150DT)。土样对Cd2+的平衡吸附量表现为BS > CK > BS+25DT > BS+50DT > BS+100DT > BS+150DT,其qm值为232.38 mmol·kg-1(100BS)。10~40℃范围内,CK、BS修饰土对Cr(Ⅵ)吸附量为增温正效应,而BS+DT复配修饰土对Cr(Ⅵ)吸附呈现自发、焓减和熵增的特征;各供试土样对Cd2+的吸附均表现为自发、焓增和熵增的特征。随着pH值的升高,各修饰土样对Cr(Ⅵ)的吸附量均逐渐降低,而对Cd2+的吸附量逐渐增加。离子强度增加不利于供试土样对Cr(Ⅵ)和Cd2+的吸附。BS+DT复配修饰膨润土表面的电荷类型、电荷数量是决定Cr(Ⅵ)和Cd2+吸附差异的主要因素。
英文摘要:
      In order to compare the discrepancies between Cr(Ⅵ) and Cd2+ adsorption on bentonite modified by a mixture of amphoteric modifier, dodecyldimethyl betaine(BS-12), and cationic modifier, Dodecyltrimethyl ammonium Bromide(DTAB), batch method was used to study the influence of temperature, ionic strength, pH on discrepancies of adsorption of Cr(Ⅵ) and Cd2+ on different modified bentonites, and the thermodynamic properties were studied also. The results showed that:The Langmuir model was suited for adsorption isotherms of Cr(Ⅵ) and Cd2+ on different samples. The equilibrium adsorption capacity of Cr(Ⅵ) was ordered by BS+150DT(BS-12+150% CEC DTAB)> BS+100DT > BS+50DT > BS+25DT > BS > CK(unmodified bentonite) and BS+150DT treatment had the maximum adsorption capacity(qm) 205.67 mmol·kg-1. On the contrary, the sequence of equilibrium adsorption capacity of Cd2+ was BS > CK > BS+25DT > BS+50DT > BS+100DT > BS+150DT, and 100BS(100% CEC BS-12) had maximum Cd2+ adsorption 232.38 mmol·kg-1. In the range of 10℃ to 40℃, the adsorption capacity of Cr(Ⅵ) on CK and BS modified bentonites were increased with increased temperature, while Cr(Ⅵ) adsorption on BS-DT bentonites was a spontaneous process with a decrease in enthalpy and an increase in entropy. The Cd2+ adsorption on different samples was a spontaneous process with an increase in enthalpy and an increase in entropy. With an increase of pH, the adsorption capacity of Cr(Ⅵ) decreased gradually, while the adsorption capacity of Cd2+ increased gradually. High ionic strength was not conducive to adsorption of Cr(Ⅵ) and Cd2+. Charge type of BS-DT complex modified bentonite was the crucial factor to difference between Cr(Ⅵ) and Cd2+ adsorption.
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