The mobility of contaminant metals in aqueous subsurface environments is largely controlled by their interaction with humic substances as colloidal constituents of Dissolved Organic Matter. Transport models for predicting carrier-bound migration are based on a competitive partitioning process between solid surface and colloids. However, it has been observed that dissociation of multivalent metals from humic complexes is a slow kinetic process, which is even more impeded with increasing time of contact. Based on findings obtained in isotope exchange experiments, the convoluted time dependence of dissociation was fully described by a complex two-site approach, integrating rate “constants” that are in turn time-dependent. Thus, this study presents the treatment of a particular phenomenon: kinetics within kinetics. The analysis showed that the inertization process does not lead to irreversible binding. Consequently, thermodynamic concepts using equilibrium constants remain applicable in speciation and transport modeling if long time frames are appropriate.

污染物金属在水性地下环境中的迁移率很大程度上受其与作为溶解有机物胶体成分的腐殖质的相互作用所控制。预测载体结合迁移的运输模型基于固体表面和胶体之间的竞争性分配过程。然而，已经观察到，多价金属从腐殖配合物中的解离是缓慢的动力学过程，随着接触时间的增加，这一过程甚至受到更大的阻碍。根据在同位素交换实验中获得的发现，通过复杂的两点方法充分描述了解离的旋绕时间依赖性，其中积分了速率“常数”，而速率常数又是时间依赖性的。因此，本研究提出了一种特殊现象的处理方法：动力学内的动力学。分析表明，惰性化过程不会导致不可逆的结合。因此，如果需要较长的时间范围，则使用平衡常数的热力学概念仍然适用于物种形成和运输模型。