【作者】 孟昭福； 李婷； 杨淑英； 任爽； 刘艳萍； 龚宁； 张斌； 李彬；

【Author】 MENG Zhao-fu 1,2 ,LI Ting,YANG Shu-ying 3 ,REN Shuang 1 ,LIU Yan-ping 3 ,GONG Ning 3 ,ZHANG Bin 1 ,LI Bin 3 (1. College of Natural Resource and Environment, Northwest A&F University, Yangling 712100, China; 2. Key Laboratory of Plant Nutrition and the Agri-environment in Northwest China, Ministry of Agriculture, Yangling 712100, China; 3.College of Science, Northwest A&F University, Yangling 712100, China)

【机构】 西北农林科技大学资源环境学院； 农业部西北植物营养与农业环境重点实验室； 西北农林科技大学理学院；

【摘要】 两性修饰土具有对有机、重金属污染物同时吸附效应,探讨不同基质的两性修饰土对有机、重金属污染物的吸附特征,对于搞清两性修饰土的吸附机制和内在规律具有十分重要的理论意义。本文以膨润土为基质,以两性修饰剂十二烷基甜菜碱(BS-12)修饰得到两性修饰膨润土,以批处理法研究其对Cd(II)的平衡吸附特征和机理。结果表明,基质CEC对于两性修饰土的吸附性能具有重要影响,以膨润土为基质的两性修饰土对Cd(II)的绝对吸塿附量显著高于土基质,但BS-12对膨润土的修饰导致其对Cd2+的吸附能力下降。当修饰比例小于100%CEC时,其对Cd2+的平衡吸附量随修饰比例的增加而减小,超出100%修饰比例后对Cd2+吸附能力则缓慢增强。两性修饰膨润土样对Cd2+吸附呈现"感温钝化"现象。苯酚的共存对低修饰比例土样吸附Cd2+具有抑制作用,而对高修饰比例土样吸附Cd2+具有促进作用。pH升高和离子强度的降低均可促进Cd2+吸附。Langmuir模型适合用来描述两性修饰膨润土样对Cd2+的平衡吸附。机理讨论认为,以电荷引力形式修饰在的膨润土表面上的BS-12不利于Cd2+吸附作用,而以疏水键形式吸附膨润土表面上的BS-12却促进了Cd2+吸附。更多还原

【Abstract】 Amphoteric modified soil(AMS) can adsorb simultaneously both organic and heavy metal pollutants, study on the different adsorption characteristics of AMS with different matrix have important theoretical significance for making clear the adsorption mechanism and inherent law of AMS. Using bentonite as a modified matrix and duodalkylbetaine(BS-12) as an amphoteric modifier, the equilibrium adsorption characteristics and mechanism of Amphoteric modified bentonite(AMB) for Cd(Ⅱ) by batch method were carried out. The results showed that cation exchange capacity(CEC) of matrix plays an important role on adsorption ability of AMS, Cd(Ⅱ) absolute adsorption capacity on AMS with bentonite as matrix is higher significantly than that with Lou soil as matrix, but the modification of BS-12 decreases the adsorption capacity of bentonite. With an increase of modification ratio, Cd(Ⅱ) equilibrium adsorption capacity decrease at 0～100% modification ratio range, while increase slowly when modification ratio exceeds 100%. The modification treatment decreases the effects of temperature on the adsorption of Cd(Ⅱ). The effect of coexist of phenol on Cd(Ⅱ) adsorption shows an inhibiting effect on AMB at low modification ratio, while shows a promoting effect on AMB at high modification ratio. Cd(Ⅱ) adsorption can enhance with an increase of pH or decline of ionic strength. Langmuir model can be used to describe the Cd(Ⅱ) adsorption isotherm. The discussion of mechanism revealed that Cd(Ⅱ) adsorption can be furthered by BS-12 adsorbed on bentonite by hydrophobic bond, but can be decreased by BS-12 adsorbed on bentonite by electrostatic attraction.更多还原