Nanoparticle size and natural organic matter composition determine aggregation behavior of polyvinylpyrrolidone coated platinum nanoparticles
Nanoparticle size and natural organic matter composition determine aggregation behavior of polyvinylpyrrolidone coated platinum nanoparticles
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DOI：
10.1039/d0en00659a
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发表时间：
2020-11
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影响因子：
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通讯作者：
M. Sikder;Jingjing Wang;Brett A. Poulin;M. Tfaily;Mohammed Baalousha
中科院分区：
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作者：
M. Sikder;Jingjing Wang;Brett A. Poulin;M. Tfaily;Mohammed Baalousha
工程纳米颗粒（NP）的大小和天然有机物质（NOM）的组成是决定纳米颗粒环境行为的重要因素。本研究的目的是研究NP大小和NOM组成如何影响聚乙烯吡咯烷酮包覆铂工程纳米颗粒（PVP-PtNPs）的胶体稳定性。我们评估了中等硬水（MHW）中NP大小（20、30、50、75和95 nm，记为PVP-PtNP20-95）对PVP-PtNP聚集的影响。此外，我们还量化了来自不同地表水的6个NOM样品中疏水有机酸（HPOA）部分对PVP-PtNP20和PVP-PtNP95聚集的影响，这些样品代表了一系列的NOM成分和性质。使用超高分辨率质谱分析表征了NOM样品的整体元素组成（如C、H、O、N和S）、254 nm处的特定紫外吸光度（SUVA254）和分子水平组成（如化合物类别）。采用单粒子电感耦合等离子体质谱法（sp-ICP-MS）监测PVP-PtNPs在1 μg PVP-PtNP / L和1 mg NOM / L浓度下的聚集。PVP-PtNP聚集体尺寸随着初级PVP-PtNP尺寸的减小而增大，这可能是由于相同质量浓度下，较小的NPs比较大的NPs具有更低的zeta电位、更高的数量浓度和更高的比表面积。在不同的NOM样品存在和不存在的情况下，在MHW中没有观察到PVP-PtNP95的聚集。在存在和不存在6种NOM样品的情况下，PVP-PtNP20在MHW中形成聚集体，并且聚集体的大小在NOM存在时增加，这可能是由于被NOM包裹的PVP-PtNPs通过二价反离子在颗粒间桥接。PVP-PtNP20的聚集体尺寸随着NOM元素H / C比和木质素/富羧基脂环分子（CRAM）类化合物的相对丰度的增加而增大。而PVP-PtNP20的聚集体尺寸随着NOM分子量、NOM SUVA254、O / C元素比、缩合烃和单宁类化合物相对丰度的增加而减小。总体而言，本研究结果表明，NOM的组成和来源是影响水生环境中PVP-PtNPs稳定性的关键因素。
Engineered nanoparticle (NP) size and natural organic matter (NOM) composition play important roles in determining NP environmental behaviors. The aim of this work was to investigate how NP size and NOM composition influence the colloidal stability of polyvinylpyrrolidone coated platinum engineered nanoparticles (PVP-PtNPs). We evaluated PVP-PtNP aggregation as a function of the NP size (20, 30, 50, 75, and 95 nm, denoted as PVP-PtNP20–95) in moderately hard water (MHW). Further, we quantified the effect of the hydrophobic organic acid (HPOA) fraction of NOM on the aggregation of PVP-PtNP20 and PVP-PtNP95 using 6 NOM samples from various surface waters, representing a range of NOM compositions and properties. NOM samples were characterized for bulk elemental composition (e.g., C, H, O, N, and S), specific ultraviolet absorbance at 254 nm (SUVA254), and molecular level composition (e.g., compound classes) using ultrahigh resolution mass spectrometry. Single particle-inductively coupled plasma-mass spectrometry (sp-ICP-MS) was employed to monitor the aggregation of PVP-PtNPs at 1 μg PVP-PtNP per L and 1 mg NOM per L concentrations. PVP-PtNP aggregate size increased with decreasing primary PVP-PtNP size, likely due to the lower zeta potential, the higher number concentration, and the higher specific surface area of smaller NPs compared to larger NPs at the same mass concentration. No aggregation was observed for PVP-PtNP95 in MHW in the presence and absence of the different NOM samples. PVP-PtNP20 formed aggregates in MHW in the presence and absence of the six NOM samples, and aggregate size increased in the presence of NOM likely due to interparticle bridging of NOM-coated PVP-PtNPs by divalent counterions. PVP-PtNP20 aggregate size increased with the increase in NOM elemental ratio of H to C and the relative abundance of lignin-like/carboxyl rich-alicyclic molecules (CRAM)-like compounds. However, the aggregate size of PVP-PtNP20 decreased with the increase in NOM molecular weight, NOM SUVA254, elemental ratio of O to C, and the relative abundance of condensed hydrocarbons and tannin-like compounds. Overall, the results of this study suggest that the composition and sources of NOM are key factors that contribute to the stability of PVP-PtNPs in the aquatic environment.