In mining regions, flotation reagents can interact with heavy metals, thereby increasing the complexity of their migration. However, most current studies solely focus on the migration of heavy metals, neglecting the influence of flotation reagents in their models concerning mining area pollution. This study developed the reactive transport model, Multisurface Speciation Model (MSM), which integrated the reaction processes of the three main soil components (iron oxides, organic matter, clay minerals) and ethyl xanthate (EX), a typical flotation reagent, with cadmium (Cd²⁺) to investigate the effects of EX on the transport and retention of Cd²⁺ in natural porous media under varying pH conditions. The study revealed that EX formed new adsorption sites for Cd²⁺, enhancing its retention and inhibiting transport with increased EX loading (0 to 2.5 mmol·L−1), while higher pH levels (ranging from 4 to 8) further strengthened the retention capability of Cd²⁺. The MSM further predicted the solid-phase concentration distribution of Cd²⁺ among various components. With increasing EX-loaded concentrations, xanthate became the dominant adsorbing component, accounting for 48.93 % to 95.31 % of adsorption, and competitively interacted with other components. Xanthate retention was lower under acidic conditions compared to neutral and alkaline environments. Sensitivity analysis highlighted the concentrations of iron oxide adsorption sites (SurfaOH, SurfbOH) as critical parameters in the models, underscoring the need for precise determination of soil physicochemical indicators. This study stressed the crucial role of flotation reagents and pH conditions in controlling heavy metal mobility, offering important insights for environmental management in mining regions.

中文翻译：

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黄原酸盐存在下 Cd2+ 在多孔介质中的反应性转运：实验和建模研究


在矿区，浮选试剂会与重金属相互作用，从而增加其迁移的复杂性。然而，目前的大多数研究只关注重金属的迁移，而忽略了浮选试剂在其关于矿区污染的模型中的影响。本研究开发了反应性传输模型，即多表面形态模型 （MSM），该模型将三种主要土壤成分（氧化铁、有机质、粘土矿物）和乙基黄原酸酯 （EX）（一种典型的浮选试剂）与镉 （Cd²⁺） 的反应过程相结合，以研究 EX 对 Cd²⁺ 在不同 pH 条件下在天然多孔介质中的传输和保留的影响。研究表明，EX 为 Cd²⁺ 形成了新的吸附位点，随着 EX 载样量（0 至 2.5 mmol·L−1），而较高的 pH 值（范围为 4 至 8）进一步增强了 Cd²⁺ 的保留能力。MSM 进一步预测了 Cd²⁺ 在各种组分之间的固相浓度分布。随着 EX 负载浓度的增加，黄药成为主要吸附组分，占吸附的 48.93 % 至 95.31 %，并与其他组分竞争相互作用。与中性和碱性环境相比，酸性条件下的黄原酸盐保留率较低。敏感性分析强调了氧化铁吸附位点 （SurfaOH、SurfbOH） 的浓度是模型中的关键参数，强调了精确测定土壤理化指标的必要性。本研究强调了浮选试剂和 pH 条件在控制重金属迁移率方面的关键作用，为矿区环境管理提供了重要见解。