Due to their use in various domestic and industrial formulations, benzalkonium compounds have been isolated in many environmental matrices. Sorption to soil components has been shown to play a key role in their environmental fate. Whereas sorption of benzalkonium compounds to soils is attributed to cation exchange and van der Waals forces, the relative contributions of these two mechanisms at environmental levels have not been clearly defined. In this study a previously reported algal toxicity assay-based method was employed to determine the distribution coefficients (Kd) of benzalkonium compounds between water and soil components, at environmental concentrations. Cation exchange capacity corrected Kd values for organic matter and clays were all within one order of magnitude. This implies that ion exchange is the dominant mechanism of sorption for benzalkonium compounds. When the sorption data were used to compute sorption energies for four homologues of benzalkonium ions, the magnitude of the free energy change of sorption increased with size of the molecule. The increase in sorption energy could be partly explained by increased energy of hydration with addition of methylene groups to the alkyl chain. A model that predicts sorption coefficients of benzalkonium compounds to soils using organic carbon content and cation exchange capacity was also defined. When tested using an artificial soil, the model estimates were all within one order of magnitude of the experimental values.

中文翻译：

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苯并铵离子对泥炭和粘土的吸附：离子交换和范德华相互作用的相对贡献。

由于它们在各种家庭和工业配方中的用途，因此已在许多环境基质中分离出苯扎氯铵化合物。事实证明，对土壤成分的吸附在其环境命运中起着关键作用。尽管苯扎氯铵化合物在土壤中的吸附归因于阳离子交换和范德华力，但在环境水平上这两种机理的相对贡献尚未明确。在这项研究中，采用先前报道的基于藻类毒性试验的方法来确定环境浓度下苯扎氯铵化合物在水和土壤成分之间的分布系数（Kd）。阳离子交换容量校正后的有机物和粘土的Kd值均在一个数量级内。这意味着离子交换是苯扎氯铵化合物吸附的主要机理。当使用吸附数据计算苯扎氯铵离子四个同系物的吸附能时，吸附自由能变化的幅度随分子大小而增加。吸附能的增加可以部分解释为在烷基链上添加亚甲基后，水合能增加。还定义了一个模型，该模型使用有机碳含量和阳离子交换容量预测苯并铵化合物对土壤的吸附系数。使用人造土壤进行测试时，模型估算值均在实验值的一个数量级内。吸附的自由能变化的幅度随分子大小而增加。吸附能的增加可以部分解释为在烷基链上添加亚甲基后，水合能增加。还定义了一个模型，该模型使用有机碳含量和阳离子交换容量预测苯并铵化合物对土壤的吸附系数。当使用人造土壤进行测试时，模型估算值均在实验值的一个数量级之内。吸附的自由能变化的幅度随分子大小而增加。吸附能的增加可以部分解释为在烷基链上添加亚甲基后，水合能增加。还定义了一个模型，该模型使用有机碳含量和阳离子交换容量预测苯并铵化合物对土壤的吸附系数。当使用人造土壤进行测试时，模型估算值均在实验值的一个数量级之内。还定义了一个模型，该模型使用有机碳含量和阳离子交换容量预测苯并铵化合物对土壤的吸附系数。当使用人造土壤进行测试时，模型估算值均在实验值的一个数量级之内。还定义了一个模型，该模型使用有机碳含量和阳离子交换容量预测苯并铵化合物对土壤的吸附系数。当使用人造土壤进行测试时，模型估算值均在实验值的一个数量级之内。