• 关键词：复配修饰  塿土  重金属Cd²⁺  吸附解吸

• 基金项目：国家自然科学基金(No.40301021)

• 刘源辉
• 西北农林科技大学理学院, 杨凌 712100

• 孟昭福
• 西北农林科技大学理学院, 杨凌 712100

• 白俊风
• 西北农林科技大学理学院, 杨凌 712100

• 秦普学
• 西北农林科技大学资源环境学院, 杨凌 712100

• 郑萍英
• 西北农林科技大学资源环境学院, 杨凌 712100

• 冀燕
• 西北农林科技大学理学院, 杨凌 712100

• 摘要：以十二烷基二甲基甜菜碱(BS-12)单一修饰和十二烷基二甲基甜菜碱+十二烷基磺酸钠(SDS)复配修饰塿土黏化层土壤,采用批处理法研究了Cd²⁺在供试土样上的吸附-解吸行为,并对其吸附-解吸机制进行了探讨.结果表明,在20℃、40℃下起始浓度较小时,复配修饰土样吸附量大于BS-12单一修饰土样,温度对吸附的影响不大.Langmuir模型最适合描述供试土样对Cd²⁺的吸附等温线.复配修饰土样20℃、40℃解吸量差异不大,原土和BS-12单一修饰土样随温度升高解吸量增加.土样净吸附量20℃时BS-12单一修饰土样最高,而复配修饰土样和原土差异不大,40℃时复配修饰和单一修饰土样差异不大,但均高于原土.复配土样的吸附是静电作用和有机修饰剂有机相的疏水阻力综合作用的结果.

• Abstract：Using batch experiments,the adsorption and desorption of Cd²⁺ on clay layer of Lou soil modified with dodecyl-dimethyl-betaine(BS-12) and dodecyl-dimethyl-betaine + sodium dodecyl-sulphonate(BS-12+SDS) mixture were investigated,and the mechanisms of adsorption and desorption were illustrated. The results showed that when the initial concentration was low the amount of Cd²⁺ adsorbed on soils modified with BS-12+SDSmixtures was higher than that of soils modified with BS-12. The temperature (20℃ and 40℃) has little influence on Cd²⁺ adsorption.The Langmuir model best describes the Cd²⁺ adsorption isotherm. The difference of the amount of desorption for soils modified with BS-12+SDSwas small between 20℃ and 40℃ while that of CKand soils modified with BS-12 increased with temperature.The net amount adsorbed was the highest for soil modified with BS-12 while the difference between CKand soil modified with BS-12+SDSwas not obvious at 20℃. At 40℃,the soil modified with BS-12+SDSand BS-12 performed similarly and the net amount adsorbed was higher than that of CK. Cadmium adsorption by soils modified with BS-12+SDSmixture was the result of a combination of electrostatic interactions and hydrophobic interactions with the organic modifiers.

• Key words：mixture modification  lou soil  heavy metal Cd²⁺  adsorption and desorption

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