三种胡敏酸对阿特拉津的吸附特性及机理研究

Adsorption Characteristics and Mechanism of Atrazine on Three Types of Humic Acid

研究了3种不同来源的胡敏酸对阿特拉津的吸附特性和吸附机理。文中针对黑土胡敏酸、栗钙土胡敏酸和市售胡敏酸样品,采用批量平衡震荡法进行其对除草剂阿特拉津的吸附实验,并利用傅里叶红外光谱和电子顺磁共振波谱两种分析方法探讨其吸附机理。结果表明:3种胡敏酸对阿特拉津的吸附均是一个先快后慢的过程,其动力学曲线均符合对数和双曲线函数关系。3种胡敏酸对阿特拉津等温吸附线均为L型曲线,且符合线性模型和Freundlich模型,其中市售胡敏酸因其结构差异与土壤提取胡敏酸等温吸附线存在明显差异。IR分析表明,胡敏酸与阿特拉津之间存在氢键、质子转移、电荷转移和范德华力等弱作用力;而ESR检测证实胡敏酸与阿特拉津在吸附过程中发生了电荷转移。

This study mainly researched the adsorption properties and adsorption mechanism of atrazine on three different types of humic acids： the black soil humic acid,the chestnut soil humic acid and the humic acid purchased.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 atrazine and humic acid.The results showed that the sorption of humic acid on atazine was very fast at the beginning,then went to slower and finally came to equilibrium.The relationship between the amount of atrazine sorbed by the three humic acids and reaction time all fitted logarithmic and hyperbolic equations well.Adsorption isotherms of atrazine on the three humic acids all are L-type and in accordance with the linear model and the Freundlich model.Because of the different structure,there is significant difference between the adsorption isotherm of atrazine on purchased humic acid and extract humic acid.The interactions between humic acid and atrazine are mostly weak forces,such as the H-bond,proton transfer,charge transfer,van der Waals force and so on.In addition,ESR analysis proved that charge transfer exists between humic acid and atrazine during the process of adsorption.