土壤重金属浸出实验模拟与模型拟合研究进展——从动力学机制到水文地球化学耦合模型

Advances in Experimental Simulation and Model Fitting of Soil Heavy Metal Leaching—From Kinetic Mechanisms to Hydrogeochemical Coupling Models

摘要: 土壤重金属污染的环境风险管控与修复，需精准量化重金属在土壤中的浸出迁移行为，现有研究在实验方法标准化、多过程耦合模型构建及实验室向现场推理方面仍存在瓶颈。梳理了批次浸出、柱浸、连续流动浸出等实验方法体系，剖析了重金属浸出的动力学机制、非饱和土壤水动力学传输方程与水地球化学耦合模型的理论框架，对比了不同模型的适用边界与性能局限。pH、液固比是调控重金属浸出行为的核心环境参数，伪二级动力学模型能够较好描述化学吸附主导的浸出过程，HP1、PHREEQC等耦合模型在多组分反应迁移模拟中具显著优势，机器学习与物理模型的融合为复杂场景下的浸出预测提供了新的技术路径。研究成果可为土壤重金属浸出行为的精准模拟、污染风险评估与修复方案优化提供系统的理论支撑与方法参考。

Abstract: The environmental risk management and remediation of soil heavy metal contamination require accurate quantification of the leaching and transport behavior of heavy metals in soils. Current research still faces bottlenecks in the standardization of experimental methods, the construction of multi-process coupled models, and the extrapolation from laboratory to field conditions. This paper reviews experimental method systems including batch leaching, column leaching, and continuous-flow leaching, analyzes the kinetic mechanisms of heavy metal leaching, the theoretical framework of unsaturated soil water dynamics and transport equations and coupled hydrogeochemical models, and compares the applicability boundaries and performance limitations of different models. pH and liquid-to-solid ratio are key environmental parameters regulating the leaching behavior of heavy metals. The pseudo-second-order kinetic model can effectively describe the leaching process dominated by chemisorption. Coupled models such as HP1 and PHREEQC exhibit significant advantages in multicomponent reactive transport simulation. The integration of machine learning with physical models provides a new technical pathway for leaching prediction under complex scenarios. The findings can provide systematic theoretical support and methodological reference for the precise simulation of soil heavy metal leaching behavior, contamination risk assessment, and optimization of remediation strategies.