胞外聚合物促进饱和多孔介质中 Cu 和 Cd 的吸附和迁移。

Extracellular Polymeric Substances Facilitate the Adsorption and Migration of Cu and Cd in Saturated Porous Media.

机构信息

Key Laboratory of Groundwater Resources and Environment, Jilin University, Ministry of Education, Changchun 130021, China.

Jilin Provincial Key Laboratory of Water Resources and Environment, Jilin University, Changchun 130021, China.

出版信息

Biomolecules. 2021 Nov 17;11(11):1715. doi: 10.3390/biom11111715.

Heavy metal contamination in groundwater is a serious environmental problem. Many microorganisms that survive in subsurface porous media also produce extracellular polymeric substances (EPS), but little is known about the effect of these EPS on the fate and transport of heavy metals in aquifers. In this study, EPS extracted from soil with a steam method were used to study the adsorption behaviors of Cu and Cd, employing quartz sand as a subsurface porous medium. The results showed that EPS had a good adsorption capacity for Cu (13.5 mg/g) and Cd (14.1 mg/g) that can be viewed using the Temkin and Freundlich models, respectively. At a pH value of 6.5 ± 0.1 and a temperature of 20 °C, EPS showed a greater affinity for Cu than for Cd. The binding force between EPS and quartz sand was weak. The prior saturation of the sand media with EPS solution can significantly promote the migration of the Cu and Cd in sand columns by 8.8% and 32.1%, respectively. When treating both metals simultaneously, the migration of Cd was found to be greater than that of Cu. This also demonstrated that EPS can promote the co-migration of Cu and Cd in saturated porous media.

地下水重金属污染是一个严重的环境问题。许多在地下多孔介质中生存的微生物也会产生细胞外聚合物物质（EPS），但对于这些 EPS 对含水层中重金属的命运和迁移的影响知之甚少。在这项研究中，使用蒸汽法从土壤中提取 EPS，并用石英砂作为地下多孔介质来研究 Cu 和 Cd 的吸附行为。结果表明，EPS 对 Cu（13.5mg/g）和 Cd（14.1mg/g）具有良好的吸附能力，分别可以用 Temkin 和 Freundlich 模型来表示。在 pH 值为 6.5±0.1 和温度为 20°C 的条件下，EPS 对 Cu 的亲和力大于 Cd。EPS 与石英砂之间的结合力较弱。EPS 溶液预先饱和砂介质可以分别显著促进 Cu 和 Cd 在砂柱中的迁移 8.8%和 32.1%。当同时处理两种金属时，发现 Cd 的迁移大于 Cu。这也表明 EPS 可以促进饱和多孔介质中 Cu 和 Cd 的共迁移。