Department of Environmental Engineering, Technical University of Denmark, Miljøvej, Building 113, 2800, Kgs. Lyngby, Denmark.
Department of Micro- and Nanotechnology, Technical University of Denmark, Ørsteds Plads, Building 345 East, 2800, Kgs. Lyngby, Denmark.
Environ Sci Pollut Res Int. 2019 Oct;26(28):29460-29472. doi: 10.1007/s11356-019-06132-8. Epub 2019 Aug 10.
The stability of gold nanoparticles (AuNPs) stabilized electrostatically with citrate or (electro)sterically by commercially available amphiphilic block copolymers (PVP-VA or PVA-COOH) was studied under various physicochemical conditions. Subsequently, the mobility of the AuNPs in porous media (sand) was investigated in column studies under environmental relevant physicochemical conditions. Electrostatically stabilized AuNPs were unstable under most physicochemical conditions due to the compression of the electrical double layer. Consequently, aggregation and deposition rapidly immobilized the AuNPs. Sterically stabilized AuNPs showed significantly less sensitivity towards changes in the physicochemical conditions with high stability, high mobility with negligible retardation, and particle deposition rate coefficients ranging an order of magnitude (1.5 × 10 to 1.5 × 10 min) depending on the type and amount of stabilizer, and thereby the surface coverage and attachment affinity. The transport of sterically stabilized AuNPs is facilitated by reversible deposition in shallow energy minima with continuous reentrainment and blocking of available attachment sites by deposited AuNPs. The stability and mobility of NPs in the environment will thereby be highly dependent on the specific stabilizing agent and variations in the coverage on the NP. Under the given experimental conditions, transport distances of the most mobile AuNPs of up to 20 m is expected. Due to their size-specific plasmonic properties, the easily detectable AuNPs are proposed as potential model or tracer particles for studying transport of various stabilized NPs under environmental conditions.
研究了在不同物理化学条件下，通过静电稳定（带负电的金纳米粒子 AuNPs 用柠檬酸盐稳定）或通过商业可得的两亲嵌段共聚物（PVP-VA 或 PVA-COOH）的空间位阻稳定（带负电的 AuNPs 用 PVP-VA 或 PVA-COOH 稳定）的 AuNPs 的稳定性。随后，在环境相关的物理化学条件下，通过柱研究研究了 AuNPs 在多孔介质（沙子）中的迁移性。由于双电层的压缩，大多数物理化学条件下静电稳定的 AuNPs 是不稳定的。因此，聚集和沉积迅速使 AuNPs 固定。由于高稳定性、高迁移率（无明显滞后）和粒径沉积速率系数（取决于稳定剂的类型和数量，范围为 1.5×10 到 1.5×10 min），空间位阻稳定的 AuNPs 对物理化学条件的变化的敏感性较小，AuNPs 的粒径沉积速率系数范围为 1.5×10 到 1.5×10 min。从而，取决于稳定剂的类型和数量，从而取决于表面覆盖率和附着亲和力。AuNPs 的传输是通过在浅能量最小势能处的可逆沉积来促进的，沉积的 AuNPs 连续重新捕获和阻止可用的附着位点。因此，NP 在环境中的稳定性和迁移性将高度取决于特定的稳定剂和 NP 覆盖度的变化。在给定的实验条件下，预计最易迁移的 AuNPs 的迁移距离可达 20 m。由于其尺寸特异性的等离子体特性，易于检测的 AuNPs 被提议作为潜在的模型或示踪粒子，用于研究在环境条件下各种稳定的 NPs 的迁移。
