The properties of the solution matrix play a prominent role in determining the interactions between the silver nanoparticles (AgNPs) when they are present in the aquatic environment. Here, using in situ liquid cell transmission electron microscopy (LCTEM), we show that the interaction of AgNPs is predominantly affected by the solution pH. Reducing the pH in the solution will accelerate the aggregation of AgNPs due to the alteration of the charge cloud around the NPs. Aggregates formed in this scenario were non spherical and irregular shaped and were stable under the electron beam irradiation. Individual AgNPs and smaller aggregates moved randomly and approached the larger aggregates before the aggregation process came to an end. We found that during the aggregation process, the mode of jump to contact and the pairwise approach of aggregation differed according to the composition of the solution. Observations made using the LCTEM were further explained using empirical formulae. Our observation on the pH induced interactions provides important insights on predicting the behavior of AgNPs released through many anthropogenic activities in the environment.

中文翻译：

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使用原位液体细胞透射电子显微镜观察水基质中酸介导的银纳米粒子 (AgNPs) 的相互作用

当它们存在于水生环境中时，溶液基质的特性在确定银纳米粒子 (AgNPs) 之间的相互作用方面起着重要作用。在这里，使用原位液体细胞透射电子显微镜 (LCTEM)，我们表明 AgNPs 的相互作用主要受溶液 pH 值的影响。由于 NPs 周围的电荷云的改变，降低溶液中的 pH 值将加速 AgNPs 的聚集。在这种情况下形成的聚集体是非球形和不规则形状的，并且在电子束照射下是稳定的。单个 AgNPs 和较小的聚集体随机移动并在聚集过程结束之前接近较大的聚集体。我们发现在聚合过程中，跳跃到接触的方式和聚集的成对方法根据溶液的组成而不同。使用经验公式进一步解释了使用 LCTEM 进行的观察。我们对 pH 诱导的相互作用的观察为预测通过环境中的许多人为活动释放的 AgNPs 的行为提供了重要的见解。