稳定机制对银纳米粒子聚集动力学的影响。

The impact of stabilization mechanism on the aggregation kinetics of silver nanoparticles.

机构信息

Dept. of Environmental Engineering, College of Engineering and Applied Science, University of Cincinnati, Cincinnati, OH, USA.

出版信息

Sci Total Environ. 2012 Jul 1;429:325-31. doi: 10.1016/j.scitotenv.2012.03.041. Epub 2012 May 10.

Abstract

The use of silver nanoparticles (AgNPs) for various applications is growing drastically. The increase in use will eventually lead to their release into the environment. The tendency of AgNPs to aggregate and the kinetics of aggregation are major factors that govern their fate in the environment. Dynamic light scattering (DLS) was utilized to investigate the electrolyte-induced aggregation kinetics (NaNO₃, NaCl and Ca(NO₃)₂) of coated and uncoated AgNPs which are electrostatically (H₂-AgNPs and Citrate-AgNPs), sterically (polyvinylpyrrolidone (PVP)-AgNPs) and electrosterically (branched polyethyleneimine (BPEI)-AgNPs) stabilized. The aggregation kinetics of the electrostatically stabilized AgNPs was in agreement with the classical Derjaguin-Landau-Verwey-Overbeek (DLVO) theory and the AgNPs exhibited both reaction-limited and diffusion-limited regimes. The H₂-AgNPs had critical coagulation concentrations (CCC) of 25, 30 and 3mM in the presence of NaNO₃, NaCl and Ca(NO₃)₂ salts, respectively. The Citrate-AgNPs had CCC of 70, 70 and 5 mM in the presence of NaNO₃, NaCl and Ca(NO₃)₂ salts, respectively. The values of the Hamaker constant for the electrostatically stabilized AgNPs were also determined and the values were in agreement with the reported values for metallic particles. The aggregation kinetics for both the sterically and electrosterically stabilized AgNPs (PVP-AgNPs and BPEI-AgNPs) was not in agreement with the DLVO theory and the particles were resistant to aggregation even at high ionic strength and electrolyte valence. The PVP-AgNPs and the BPEI-AgNPs had no critical aggregation concentration value at the investigated ionic strength values.

摘要

银纳米粒子(AgNPs)在各种应用中的使用正在迅速增加。使用量的增加最终将导致它们释放到环境中。AgNPs 聚集的趋势和聚集的动力学是控制它们在环境中命运的主要因素。动态光散射(DLS)被用于研究涂覆和未涂覆的 AgNPs 的电解质诱导聚集动力学(NaNO₃、NaCl 和 Ca(NO₃)₂),这些 AgNPs 分别通过静电(H₂-AgNPs 和柠檬酸盐-AgNPs)、空间位阻(聚乙烯吡咯烷酮(PVP)-AgNPs)和电动位阻(支化聚乙烯亚胺(BPEI)-AgNPs)稳定。静电稳定的 AgNPs 的聚集动力学与经典的德加古林-兰德沃维-奥弗贝克(DLVO)理论一致,AgNPs 表现出反应限制和扩散限制两种状态。在存在 NaNO₃、NaCl 和 Ca(NO₃)₂盐的情况下,H₂-AgNPs 的临界聚沉浓度(CCC)分别为 25、30 和 3mM。在存在 NaNO₃、NaCl 和 Ca(NO₃)₂盐的情况下,柠檬酸盐-AgNPs 的 CCC 分别为 70、70 和 5mM。还确定了静电稳定的 AgNPs 的哈马克常数的值,并且这些值与金属颗粒的报道值一致。空间位阻和电动位阻稳定的 AgNPs(PVP-AgNPs 和 BPEI-AgNPs)的聚集动力学也不符合 DLVO 理论,即使在高离子强度和电解质价态下,颗粒也不易聚集。在研究的离子强度值下,PVP-AgNPs 和 BPEI-AgNPs 没有临界聚集浓度值。

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