Zhang Taoying, Xing Yuhang, Zhang Jianguo, Li Xiong
Ministry of Agriculture Key Laboratory of Plant Nutrition and the Agri-environment in Northwest China, College of Natural Resources and Environment, Northwest A & F University, Yangling 712100, Shaanxi, China; Key Laboratory of Low-carbon Green Agriculture in Northwestern China, Ministry of Agriculture and Rural Affairs, P. R. China, Yangling 712100, China.
Ministry of Agriculture Key Laboratory of Plant Nutrition and the Agri-environment in Northwest China, College of Natural Resources and Environment, Northwest A & F University, Yangling 712100, Shaanxi, China; Key Laboratory of Low-carbon Green Agriculture in Northwestern China, Ministry of Agriculture and Rural Affairs, P. R. China, Yangling 712100, China.
Sci Total Environ. 2024 Dec 1;954:176459. doi: 10.1016/j.scitotenv.2024.176459. Epub 2024 Sep 23.
Humic acid (HA) is of great importance in controlling the fate of heavy metals (HMs), however, the pivotal influence of HA aggregation within the HA-clay-HM ternary system on retarding HM mobility remains obscure. This study performed molecular dynamics simulations to delve into the consequences of HA aggregation on the environmental behavior of Cd and Pb (0.1-0.6 M) in the co-existence of illite particles. HA can readily aggregate into clusters, adhering to the illite surface or freely dispersing in the solution. These HA clusters significantly modulate HM mobility, contingent upon their location, arrangement, and interaction with illite. Consequently, HA exhibited a pronounced retardation effect on HM migration, stemming from the competition between HA aggregation and its adsorption on illite. Additionally, the retardation effect of HA aggregation was more obvious for Cd (as compared to Pb), owing to its stronger interaction with the functional groups of HA. These findings contribute to the development of potential HA-based strategies for remediation of heavy metal-contaminated sites.
腐殖酸（HA）在控制重金属（HMs）的归宿方面具有重要意义，然而，在HA-粘土-HM三元体系中，HA聚集对延缓HM迁移率的关键影响仍不清楚。本研究进行了分子动力学模拟，以深入探究在伊利石颗粒共存的情况下，HA聚集对Cd和Pb（0.1 - 0.6 M）环境行为的影响。HA很容易聚集成簇，附着在伊利石表面或在溶液中自由分散。这些HA簇显著调节HM迁移率，这取决于它们的位置、排列以及与伊利石的相互作用。因此，由于HA聚集与其在伊利石上的吸附之间的竞争，HA对HM迁移表现出明显的阻滞作用。此外，由于Cd与HA官能团的相互作用更强，HA聚集对Cd的阻滞作用比对Pb更明显。这些发现有助于开发基于HA的潜在策略来修复重金属污染场地。
