极化效应在土壤/矿物表面重金属吸附中的重要调控作用
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界面过程与土壤健康重庆市重点实验室

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重庆市自然科学基金项目(CSTB2025NSCQ-LZX0021)资助


The Significant Regulatory Role of the Polarization Effects in the Adsorption of Heavy Metals on Soil/Mineral Surfaces
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Chongqing Key Laboratory of Interfacial Processes and Soil Health, College of Resources and Environment, Southwest University

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Supported by the Natural Science Foundation Project of Chongqing, China (No. CSTB2025NSCQ-LZX0021)

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    摘要:

    土壤/矿物中吸附作用是重金属污染修复的重要过程之一。由于对土壤/矿物独特性质缺乏深刻理解,重金属吸附的界面反应机制仍不明确。基于轨道杂化理论,结合表面性质评估、重金属离子吸附过程以及红外光谱技术,探讨了极化效应对重金属吸附的影响,明确了土壤/矿物界面各作用力对总吸附能的贡献。结果表明,(1)不同类型颗粒的比表面积和表面电荷数量均表现出由高到低依次为恒电荷蒙脱石、恒电荷为主的紫色土、可变电荷黄壤,但表面负电荷密度和负电场强度整体均表现出由高到低依次为紫色土、黄壤、蒙脱石;(2)土壤/矿物表面电荷密度和电场强度随pH升高而增大,且重金属吸附表现出强烈的离子特异性效应;(3)极化效应增强了重金属的吸附能力,不同类型颗粒表面重金属离子的吸附能力由强到弱依次为蒙脱石、紫色土、黄壤;(4)吸附能大小与离子强度呈负相关,而与pH呈正相关关系,各吸附能分量表现为库仑能、共价能、极化能依次降低,表明吸附过程依赖于极化效应的共价作用,并且极化作用仍然弱于库仑作用;(5)重金属的极化效应对其吸附具有重要调控作用,吸附强度可通过表面电场进行调节,表面电场依赖于pH和表面电荷密度(表面电荷数量与比表面积比值)。本研究从微观界面行为揭示土壤/矿物对重金属吸附的量子机制,为土壤重金属钝化/活化调控技术奠定理论基础。

    Abstract:

    【Objective】The adsorption of heavy metals in soils/minerals is one of the key processes for heavy metal pollution remediation. Owing to an insufficient in-depth understanding of the unique properties of soils/minerals, the interfacial reaction mechanism of heavy metal adsorption remains unclear. Therefore, this study aimed to investigate the regulatory effects of polarization on heavy metal adsorption at the soil/mineral interface, and quantitatively clarify the contribution of each interaction force to the total adsorption energy.【Method】Based on orbital hybridization theory, combined with surface property evaluation, heavy metal ion adsorption experiments, and Fourier-transform infrared (FTIR) spectroscopy, it was systematically investigated the regulatory effects of polarization on heavy metal adsorption at the soil/mineral interface, and quantitatively clarified the contribution of each interaction force to the total adsorption energy. 【Result】The results showed that: (1) Both the specific surface area and surface charge quantity followed the order: permanent-charged montmorillonite > permanent-charge-dominated purple soil > variable-charged yellow soil. However, the surface negative charge density and negative electric field strength generally followed the sequence of purple soil > yellow soil > montmorillonite. (2) The surface charge density and electric field strength of soils/minerals increased with increasing pH, and exhibited a significant ion specificity. The adsorption capacity followed Pb2+ > Zn2+ > Cu2+ > Cd2+ on the montmorillonite surfaces, and Pb2+ > Cu2+ > Cd2+ > Zn2+ on purple soil surfaces at low concentrations. As the equilibrium concentration increased, the adsorption rate of Cu2+ gradually became lower than that of Cd2+ and Zn2+, following Pb2+ > Cu2+ > Cd2+ > Zn2+ on yellow soil surfaces. (3) The polarization effects enhanced the heavy metal adsorption ability, and the adsorption capacity of heavy metal cations followed montmorillonite > purple soil > yellow soil. (4) The adsorption energy was negatively correlated with ionic strength but positively correlated with pH. The components of adsorption energy followed the order: Coulomb energy > Covalent energy > Polarization energy, indicating that the covalent and polarization forces, dependent on the polarization effects, were still weaker than the Coulomb force. (5) The polarization effects of heavy metals played a crucial regulatory role in their adsorption. Moreover, the adsorption intensity could be regulated by the polarization effect through the surface electric field, which depended on pH and surface charge density (the ratio of surface charge quantity to specific surface area). 【Conclusion】This study revealed the quantum mechanism of heavy metal adsorption on soils/minerals from the perspective of micro-interfacial behavior, laying a theoretical foundation for the development of soil heavy metal passivation/activation regulation technologies.

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席淑宁,刘新敏,曲佳雯,唐雨婷,李航.极化效应在土壤/矿物表面重金属吸附中的重要调控作用[J].土壤学报,DOI:10.11766/trxb202511200556,[待发表]
XI Shuning, LIU Xinmin, QU Jiawen, TANG Yuting, LI Hang. The Significant Regulatory Role of the Polarization Effects in the Adsorption of Heavy Metals on Soil/Mineral Surfaces[J]. Acta Pedologica Sinica, DOI:10.11766/trxb202511200556,[In Press]

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  • 收稿日期:2025-11-20
  • 最后修改日期:2026-05-20
  • 录用日期:2026-08-17
  • 在线发布日期: 2026-08-19
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