In this investigation, batch and column experiments were conducted to investigate the molybdenum (Mo) sorption and transport processes on a neutral-pH soil (Webster loam) and an acidic soil (Mahan sand) in Ca2+ and K+ background solutions. Batch results showed that the adsorption of Mo was strongly non-linear in both soils and amount of Mo sorbed in the acidic soil was larger than the neutral soil. The Freundlich distribution coefficients (Kf) and Langmuir sorption maxima (Smax) in Ca2+ background solution are larger than that in K+ solution, indicating greater Mo sorption in Ca2+ than in K+. Experimental breakthrough curves (BTCs) demonstrated that mobility of Mo was higher at neutral condition than that at acidic condition. A multi-reaction transport model (MRTM) formulation with two kinetic retention reactions (reversible and irreversible) well described Mo transport for Webster soil. However, MRTM model which accounts for equilibrium and kinetic sites is recommended for Mo transport in Mahan soil, reflecting different soil properties. Based on inverse modeling, the sorption forward rate coefficients (k1) obtained from Ca2+ in both soils are larger than that from K+, which consistent with batch experiment. Overall, MRTM model was capable of describing the Mo transport behavior under different geochemical conditions.

中文翻译：

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钼在土壤中吸附和迁移的动力学模型。

在这项研究中，进行了分批和柱实验，以研究Ca2 +和K +背景溶液中中性pH值土壤（韦伯斯特壤土）和酸性土壤（马汉砂）上钼（Mo）的吸附和迁移过程。批处理结果表明，在两种土壤中，Mo的吸附都是非线性的，酸性土壤中的Mo吸附量大于中性土壤。Ca2 +背景溶液中的Freundlich分布系数（Kf）和Langmuir吸附最大值（Smax）大于K +溶液中的Freundlich分布系数（Kf）和Langmuir吸附最大值（Smax），表明Ca2 +中的Mo吸附量大于K +中的Mo吸附量。实验突破曲线（BTCs）表明，Mo在中性条件下的迁移率高于酸性条件下的迁移率。具有两个动力学保留反应（可逆和不可逆）的多反应迁移模型（MRTM）配方很好地描述了韦伯斯特土壤的Mo迁移。但是，建议将平衡和动力学位点考虑在内的MRTM模型用于马汉土壤中的Mo运移，这反映了不同的土壤特性。基于逆模型，两种土壤中Ca2 +的吸附向前速率系数（k1）大于K +中的吸附向前速率系数（k1），这与分批实验一致。总体而言，MRTM模型能够描述不同地球化学条件下的Mo运移行为。在两种土壤中，Ca2 +的吸附向前速率系数（k1）大于K +的吸附向前速率系数，这与分批实验一致。总体而言，MRTM模型能够描述不同地球化学条件下的Mo运移行为。在两种土壤中，Ca2 +的吸附向前速率系数（k1）大于K +的吸附向前速率系数，这与分批实验一致。总体而言，MRTM模型能够描述不同地球化学条件下的Mo运移行为。