Competitive sorption between imidacloprid and imidacloprid-urea on soil clay minerals and humic acids.
Competitive sorption between imidacloprid and imidacloprid-urea on soil clay minerals and humic acids.
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DOI：
10.1021/jf0204194
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发表时间：
2002-10
影响因子：
6.1
通讯作者：
Weiping Liu;Wei Zheng;J. Gan
中科院分区：
文献类型：
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作者：
Weiping Liu;Wei Zheng;J. Gan
土壤有机质和粘土矿物是许多农药吸附的原因。采用静态平衡法研究了吡虫啉在粘土矿物和腐殖酸（HA）上的吸附和竞争吸附。腐殖酸对吡虫啉的吸附系数显著高于钙基粘土矿物，表明土壤有机质含量是影响吡虫啉吸附的重要因素。研究了吡虫啉及其主要代谢产物吡虫啉-尿素在HA和Ca-粘土矿物上的竞争吸附。结果表明，吡虫啉在土壤中的代谢产物可降低其在粘土矿物和腐殖酸上的吸附量，表明吡虫啉-尿素可占据或阻断其在土壤中的吸附位点，从而影响其在环境中的归趋、迁移和生物有效性。用红外差谱法研究了钙粘土和HA粘土混合物对吡虫啉和吡虫啉-尿素的吸附作用。从吸附后吡虫啉和吡虫啉-尿素的特征红外吸收带的位移探讨了可能的吸附机理。
Soil organic matter and clay minerals are responsible for the adsorption of many pesticides. Adsorption and competitive sorption of imidacloprid on clay minerals and humic acids (HA) were determined using the batch equilibration method. The sorption coefficient of imidacloprid on humic acids was significantly higher than that on Ca-clay minerals, indicating that soil organic matter content was a more important property in influencing the adsorption of imidacloprid. Competitive sorption was investigated between imidacloprid and its main metabolite imidacloprid-urea on HA and Ca-clay minerals. The results showed that the sorption capacity of imidacloprid on clay minerals and HA was reduced in the presence of the metabolite, implying that imidacloprid-urea could occupy or block adsorption sites of imidacloprid on soil, potentially affecting the fate, transport, and bioavailability of imidacloprid in the environment. The interactions between a Ca-clay or HA-clay mixture and adsorption of imidacloprid and imidacloprid-urea were studied using IR differential spectra on thin films made of the adsorbent. The possible mechanisms were discussed from the shift of characteristic IR absorption bands of imidacloprid and imidacloprid-urea after sorption.