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| 基于恒电容表面络合模型CCM预测土壤中As(V)吸附行为研究 |
| Predicting adsorption of arsenate on soils based on the Constant Capacitance Model |
| 投稿时间：2023-03-23 修订日期：2023-05-08 |
| DOI： |
| 中文关键词: 表面络合模型 As 吸附 恒电容模型 广义复合模式 |
| 英文关键词: surface complexation model As(V) adsorption CCM GC |
| 基金项目:国家重点研发计划项目(2021YFC1809102)，国家自然科学基金（42225701） |
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| 中文摘要: |
| 吸附是控制As在土壤中迁移重要过程之一，本文使用恒电容表面络合模型（CCM）模拟了As(Ⅴ)在土壤中的吸附行为，获取了As(Ⅴ)在土壤上吸附的表面络合常数，建立了土壤基本理化性质（pH、有机质、碳酸钙、无定形铁/铝/锰、总铁）与As(Ⅴ)表面络合参数的线性回归模型，以阐明As在土壤中吸附的主控因子。结果显示，As(Ⅴ)在不同类型的土壤表现出不同的吸附特征，恒电容模型能够很好地模拟As(Ⅴ)在不同pH下的吸附特性（R2在0.71-0.96之间），通过CCM模型拟合得到As(V)在土壤表面的三个表面络合常数，绝大部分土壤logK1比logK2和logK3的值要大，说明As(V)在土壤中的吸附相较于单齿络合物更偏向于形成双齿双核的络合物。As(Ⅴ)表面络合常数与土壤性质间的回归分析结果表明，As(Ⅴ)表面络合常数主要受土壤pH、无定形铁、锰含量的影响。为了进一步验证上述线性模型的普适性，利用文献数据中土壤性质数据预测不同土壤上As(Ⅴ)表面络合常数，并结合CCM模型预测了As(Ⅴ)在文献土壤中的吸附量，预测值和实测值具有很好的相关性，说明该模型具有一定的普适性。 |
| 英文摘要: |
| Adsorption is one of the important processes to control the migration of As in soil. In this paper, the constant capacitance surface complexation model CCM was used to simulate the adsorption behavior of As(Ⅴ) in soil, and the surface complexation constant of As(Ⅴ) was obtained based on CCM model. A linear regression model was established for the basic physical and chemical properties of soil (pH, organic matter, calcium carbonate, amorphous iron/aluminum/manganese, total iron) and the surface complexation constant of As(Ⅴ) to elucidate the main controlling factors of adsorption of As in soil. The results showed that As(Ⅴ) exhibited different adsorption characteristics in different types of soil at different pHs, and the constant capacitance model could well simulate the adsorption edge of As(Ⅴ) at different pH values (R2 ranged from 0.71-0.96). Three surface complexation constants of As(V) on soil surface were obtained by fitting CCM model. The values of logK1 in most soils are larger than those of logK2 and logK3, indicating that the adsorption of As(V) in soil is more inclined to form the bidentate complexes than that of monodentate. The regression analysis of As(Ⅴ) surface complexation constants and soil properties showed that the As(Ⅴ) surface complexation constants were mainly affected by soil pH and the contents of amorphous Fe and Mn. In order to further verify the universality of the above linear model, the surface complexation constants of As(Ⅴ) on different soils was predicted by the soil property data in the literature, and the adsorption capacity of As(Ⅴ) in the literature soil was also predicted by the CCM model. The predicted value and the measured value in the literature had a good correlation (R2=0.71), indicating that the model had a certain universality. In this study, based on the adsorption behavior of As(Ⅴ) in soils with different properties, the generalized complex method was used to establish a CCM model to describe the adsorption and distribution process of As(Ⅴ) in non-calcareous soils, providing theoretical support for regional soil heavy metal environmental risk prediction. |
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