Center for Environmental Nanoscience and Risk, Department of Environmental Health Sciences, Arnold School of Public Health, University South Carolina, Columbia, SC 29208, USA.
Center for Environmental Nanoscience and Risk, Department of Environmental Health Sciences, Arnold School of Public Health, University South Carolina, Columbia, SC 29208, USA.
Sci Total Environ. 2017 Mar 1;581-582:268-276. doi: 10.1016/j.scitotenv.2016.12.117. Epub 2016 Dec 30.
The attachment efficiency (α) is an important parameter that can be used to characterize nanoparticle (NPs) aggregation behavior and has been a topic of discussion of several papers in the past few years. The importance of α is because it is one of the key parameters that can be used to model NP environmental fate and behavior. This study uses UV-vis and laser Doppler electrophoresis to monitor the aggregation behavior of citrate-coated silver nanoparticles (cit-AgNPs) induced by Na and Ca as counter ions in the presence and absence of Suwannee River fulvic acid (SRFA) as a surrogate of natural organic matter and different concentrations of phosphate buffer (0-1mM). Results demonstrate that phosphate buffer, which serves to maintain pH nearly constant over the course of a reaction, is an important determinant of NP aggregation behavior. Increasing phosphate buffer concentration results in a decrease in the critical coagulation concentrations (CCC) of cit-AgNPs to lower counter ion concentration and an increase of α at the same counter ion concentration, both in the absence and presence of SRFA. SRFA stabilizes AgNPs and increases the CCC to higher counter ion concentrations. The outcome of this study can be used to rationalize the variation in α and CCC values reported in the literature for NPs with similar physicochemical properties, where different α and CCC values are reported when different types of buffers and buffer concentrations are used in different studies.
附着效率（α）是一个重要的参数，可用于描述纳米颗粒（NPs）的聚集行为，过去几年已有多篇论文对此进行了讨论。α之所以重要，是因为它是可用于模拟 NP 环境归宿和行为的关键参数之一。本研究使用紫外-可见分光光度法和激光多普勒电泳监测了在存在和不存在苏万尼河腐殖酸（SRFA）作为天然有机物替代物以及不同浓度磷酸盐缓冲液（0-1mM）的情况下，Na 和 Ca 作为抗衡离子诱导的柠檬酸包覆银纳米颗粒（cit-AgNPs）的聚集行为。结果表明，磷酸盐缓冲液在反应过程中几乎保持 pH 值恒定，是 NP 聚集行为的重要决定因素。随着磷酸盐缓冲液浓度的增加，cit-AgNPs 的临界聚沉浓度（CCC）在相同抗衡离子浓度下降低，而在不存在和存在 SRFA 的情况下，α值增加，均在相同抗衡离子浓度下。SRFA 稳定了 AgNPs 并增加了 CCC 以达到更高的抗衡离子浓度。本研究的结果可用于解释具有相似物理化学性质的 NPs 文献中报道的 α 和 CCC 值的变化，当在不同研究中使用不同类型的缓冲液和缓冲液浓度时，会报告出不同的 α 和 CCC 值。
