两种胡敏酸对2,4-D的吸附特性及机理研究  

Adsorption Characteristics and Mechanism of 2,4-D on Two Types of Humic Acid

作　　者：常春英[1] 吕贻忠[1] 

机构地区：[1]中国农业大学资源与环境学院,北京100193

出　　处：《光谱学与光谱分析》2009年第11期2926-2929,共4页Spectroscopy and Spectral Analysis

基　　金：国家"十一五"科技支撑课题项目(2006BAD15B01);国家自然科学基金项目(40771099)资助

摘　　要：研究了两种不同来源的胡敏酸对2,4-D的吸附特性和吸附机理。分别将黑土和栗钙土土壤样品提取胡敏酸,然后采用批量平衡震荡法进行吸附实验,并利用傅里叶红外光谱(FTIR)和电子顺磁共振波谱(ESR)两种分析方法探讨其机理。结果表明:黑土和栗钙土胡敏酸对2,4-D的吸附动力学曲线均是一个先快后慢的过程,吸附量基本一致,分别为0.39和0.42μg·kg-1。黑土胡敏酸结构中较多的羧酸类基团使黑土胡敏酸初始吸附速率比栗钙土胡敏酸大得多。两种胡敏酸对2,4-D等温吸附线均为L型曲线,且符合线性模型和Freundlich模型。IR分析表明,胡敏酸与2,4-D之间存在氢键、质子转移、电荷转移和范德华力等弱作用力;而ESR检测发现胡敏酸与2,4-D或其降解产物在吸附过程中产生了共价键。This study mainly focused on the adsorption properties and adsorption mechanism of 2,4-D on two different humic acids. After the extraction of humic acid from the two different types of soil,the black soil and chestnut soil,adsorption experiments were carried out using the batch equilibrium techniques. Then FTIR and ESR spectral analysis methods were employed to explain the functional mechanism between 2,4-D and humic acid. The results showed the relationship between the amount of 2,4-D sorbed by the two humic acids and the reaction time,with the adsorption process for both acids being very fast at the beginning,then becoming slower and finally reaching equilibrium. The adsorption capacity of 2,4-D on black soil humic acid and chestnut soil humic acid were 0.39 and 0.42 mg·kg^-1 respectively. More carboxylic acid structure made the initial adsorption rate of 2,4-D on black soil humic acid much faster than on chestnut soil humic acid. Adsorption isotherm of 2,4-D on the two humic acids was both in accordance with the linear model and the Freundlich model. The interactions between humic acid and 2,4-D are mostly weak forces,such as the H-bond,proton transfer,charge transfer,van der Waals force and so on. In addition,ESR analysis found that covalent bond exists between humic acid and 2,4-D or its degradation product during the process of adsorption.

关 键 词：2 4-D 胡敏酸 吸附特性 机理 FTIR ESR 

分 类 号：S482[农业科学—农药学]