Department of Land and Water Resources Engineering, KTH (Royal Institute of Technology), Teknikringen, Stockholm, Sweden.
Environ Sci Technol. 2010 Nov 15;44(22):8587-93. doi: 10.1021/es102415r.
A consistent chemical equilibrium model that calculates pH from charge balance constraints and aluminum and iron speciation in the presence of natural organic matter is presented. The model requires input data for total aluminum, iron, organic carbon, fluoride, sulfate, and charge balance ANC. The model is calibrated to pH measurements (n = 322) by adjusting the fraction of active organic matter only, which results in an error of pH prediction on average below 0.2 pH units. The small systematic discrepancy between the analytical results for the monomeric aluminum fractionation and the model results is corrected for separately for two different fractionation techniques (n = 499) and validated on a large number (n = 3419) of geographically widely spread samples all over Sweden. The resulting average error for inorganic monomeric aluminum is around 1 µM. In its present form the model is the first internally consistent modeling approach for Sweden and may now be used as a tool for environmental quality management. Soil gibbsite with a log *Ks of 8.29 at 25°C together with a pH dependent loading function that uses molar Al/C ratios describes the amount of aluminum in solution in the presence of organic matter if the pH is roughly above 6.0.
本文提出了一种从电荷平衡约束和天然有机物存在下的铝和铁形态来计算 pH 的一致化学平衡模型。该模型需要输入总铝、铁、有机碳、氟化物、硫酸盐和电荷平衡 ANC 的数据。通过仅调整活性有机物质的分数对模型进行校准，可以将 pH 预测的平均误差调整到低于 0.2 pH 单位。两种不同的分馏技术（n = 499）分别对单体铝分馏的分析结果和模型结果之间的小系统差异进行了校正，并在瑞典各地广泛分布的大量样本（n = 3419）上进行了验证。结果表明，无机单体铝的平均误差约为 1 µM。目前，该模型是瑞典第一个内部一致的建模方法，现在可以用作环境质量管理的工具。在 pH 大致高于 6.0 的情况下，如果存在有机物，土壤三水铝石（log*Ks 在 25°C 时为 8.29）和使用摩尔 Al/C 比的 pH 相关负载函数可以描述溶液中铝的含量。
