Systemic Physiological and Ecotoxicological Research (SPHERE), Department of Biology , University of Antwerp , Groenenborgerlaan 171 , 2020 Antwerp , Belgium.
Physical Chemistry and Soft Matter , Wageningen University & Research , Stippeneng 4 , 6708 WE Wageningen , The Netherlands.
Environ Sci Technol. 2019 Aug 6;53(15):8516-8532. doi: 10.1021/acs.est.9b00624. Epub 2019 Jul 24.
Latest knowledge on the reactivity of charged nanoparticulate complexants toward aqueous metal ions is discussed in mechanistic detail. We present a rigorous generic description of electrostatic and chemical contributions to metal ion binding by nanoparticulate complexants, and their dependence on particle size, particle type (i.e., reactive sites distributed within the particle body or confined to the surface), ionic strength of the aqueous medium, and the nature of the metal ion. For the example case of soft environmental particles such as fulvic and humic acids, practical strategies are delineated for determining intraparticulate metal ion speciation, and for evaluating intrinsic chemical binding affinities and heterogeneity. The results are compared with those obtained by popular codes for equilibrium speciation modeling (namely NICA-Donnan and WHAM). Physicochemical analysis of the discrepancies generated by these codes reveals the a priori hypotheses adopted therein and the inappropriateness of some of their key parameters. The significance of the characteristic time scales governing the formation and dissociation rates of metal-nanoparticle complexes in defining the relaxation properties and the complete equilibration of the metal-nanoparticulate complex dispersion is described. The dynamic features of nanoparticulate complexes are also discussed in the context of predictions of the labilities and bioavailabilities of the metal species.
讨论了带电纳米配合物与水溶液中金属离子反应性的最新知识，并从机理上进行了详细讨论。我们提出了纳米配合物对金属离子结合的静电和化学贡献的严格通用描述，以及它们对颗粒尺寸、颗粒类型（即分布在颗粒主体内或局限在表面上的反应性位点）、水介质的离子强度以及金属离子性质的依赖性。对于软环境颗粒（如腐殖酸和富里酸）的示例情况，阐述了确定颗粒内金属离子形态、评估内在化学结合亲和力和异质性的实用策略。将结果与用于平衡形态建模的流行代码（即 NICA-Donnan 和 WHAM）的结果进行了比较。对这些代码生成的差异进行的物理化学分析揭示了其中采用的先验假设以及其一些关键参数的不适当性。描述了控制金属-纳米颗粒配合物形成和解离速率的特征时间尺度对金属-纳米颗粒配合物分散体的弛豫性质和完全平衡的影响。还讨论了纳米颗粒配合物的动态特性，以及对金属物种的生物可利用性和生物活性的预测。
