Evaluation of Soil Surface Charge Using the Back-Titration Technique
Evaluation of Soil Surface Charge Using the Back-Titration Technique
复制标题
使用反滴定技术评估土壤表面电荷
DOI：
10.2136/sssaj2004.8200
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发表时间：
2004
期刊：
影响因子：
--
通讯作者：
W. Hendershot
中科院分区：
文献类型：
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作者：
Y. Ge;W. Hendershot
可变表面电荷（Qv）是控制离子在土壤固相上吸附的最重要的土壤性质之一。在这项研究中，返滴定技术被用来确定Q，具有广泛的性质的土壤。该程序将Q定义为针对固相溶解和其他溶液反应（例如，金属水解）。Qv的变化范围为0 ~ 80 cmolckg-1，与土壤悬浮液的pH值和土壤有机质含量有关。我们使用非理想竞争吸附（NICA）-唐南模型来模拟表面电荷，假设双峰分布的H +亲和力的土壤固相。利用电荷数据和Microsoft Excel优化NICA-Donnan模型参数。该模型提供了一个很好的拟合实验数据。当pH低于8时，表面电荷主要分布在1型位点;当pH > 8时，2型位点开始贡献总表面电荷。多元线性回归分析表明，两个站点的电荷最大值（Q max）与土壤阳离子交换量（CEC）和有机碳（Org. C）有关，这些显著的统计关系可用于估算土壤表面电荷，并可利用常用的土壤参数值。
Variable surface charge (Q v ) is one of the most important soil properties controlling ion adsorption on the soil solid phase. In this study, the back-titration technique was used to determine the Q, of soils with a wide range of properties. The procedure defines the Q, as the OH - consumption by surface reactions corrected for dissolution of the solid phase and other solution reactions (e.g., metal hydrolysis). The Q v , varying from 0 to 80 cmol c kg -1 , was dependent on the pH of the soil suspension and the amount of soil organic matter. We used the non-ideal competitive adsorption (NICA)-Donnan model to simulate the surface charge, assuming a bimodal distribution of H + affinity on the soil solid phase. With the charge data and Microsoft Excel, the NICA-Donnan model parameters were optimized. The model provided an excellent fit to the experimental data. When the pH was below 8, the surface charge was dominantly distributed to the Type 1 sites; the Type 2 sites started to contribute to the total surface charge at pH > 8. Multiple linear regressions showed that the charge maxima (Q max ) of the two sites were related to soil cation-exchange capacity (CEC) and organic C (Org. C); these significant statistical relationships may be used to estimate the surface charge of soils using values of commonly measured soil parameters.