Potential impact of natural organic ligands on the colloidal stability of silver nanoparticles
Potential impact of natural organic ligands on the colloidal stability of silver nanoparticles
复制标题
DOI：
10.1016/j.scitotenv.2017.12.299
复制
发表时间：
2018-06-01
影响因子：
9.8
通讯作者：
Baalousha, Mohammed
中科院分区：
文献类型：
--
作者：
Afshinnia, Kamelia;Marrone, Brandon;Baalousha, Mohammed
天然有机物(NOM)与工程纳米颗粒(NP)的相互作用决定了NP的去向、迁移和环境持久性。然而，由于纳米银和银纳米颗粒性质的异质性和变异性，纳米银的化学组成、结构和浓度对纳米银的聚集动力学和溶解行为的影响还知之甚少。本文用紫外-可见光谱研究了柠檬酸盐包覆银纳米粒子在L-半胱氨酸(L-半胱氨酸)和N-乙酰基L-半胱氨酸(N-乙酰-半胱氨酸)存在下的聚集行为。我们还考察了苏万尼河黄腐酸(SRFA)和育空河分离的NOM(YRNOM)对cit-AgNPs稳定性的影响。在0~10M范围内，随着L-Cys和NaL-CyS浓度的增加，cit-AgNPs的溶解度降低，而临界凝血浓度(Ccc)在L-Cys的存在下降低，在NaL-Cys的存在下增加。同样，L-赛斯在SRFA的存在下破坏了CIT-AgNPs的稳定。Cit-AgNPs在L-半胱氨酸和NAL-半胱氨酸存在下稳定性的差异可以归因于这两个半胱氨酸分子中官能团的不同。L-半胱氨酸既有带负电荷的羧基，又有带正电荷的胺基，导致了不同粒子之间的桥联。半胱氨酸是半胱氨酸的衍生物，其中乙酰基连接到氮原子上，从而屏蔽胺基团上的正电荷，从而消除桥联相互作用机制。SRFA和YRNOM提高了Cit-AgNPs的稳定性，并使Cc值增加到较高的反离子浓度。SRFA的浓度(1-5 mg L-1)对Cit-AgNPs的ccc没有影响，但随着YRNOM浓度的增加，cct-AgNPs的cc值增加到较高的Na+浓度，这可能是由于较高分子量化合物在cit-AgNPs表面的吸附增加所致。这项研究的结果表明，了解NOM的分子性质(如官能团和相对分子质量)对于确定Cit-AgNP的环境行为具有重要意义。(C)2017爱思唯尔B.V.保留所有权利。
Interaction of natural organic matter (NOM) with engineered nanoparticles (NPs) determine NP fate, transport, and environmental persistence. However, the effect of NOM chemical composition, structure, and concentration on aggregation kinetics and dissolution behavior of silver nanoparticles (AgNPs) are still poorly understood because of heterogeneity and variability in NOM and AgNP properties. Here, aggregation behavior of citrate-coated silver nanoparticles (cil-AgNPs with a z-average diameter of 18 nm) was investigated in the presence of L-cysteine (L-cys) and N- acetyl L-cysteine (NAL-cys) using UV-vis spectroscopy. We also investigated the effect of Suwannee River fulvic acid (SRFA) and a NOM isolated from the Yukon River (YRNOM) on the stability of cit-AgNPs. The dissolution of cit-AgNPs decreased with increased L-cys and NAL-cys concentration from 0 to 10 M. The critical coagulation concentration (CCC) of cit-AgNPs decreased in the presence of L-cys and increased in the presence of NAL-cys. Similarly, L-cys destabilizes cit-AgNPs in the presence of SRFA. The differences in the stability of cit-AgNPs in the presence of L-cys and NAL-cys can be attributed to the differences in the functional groups in these two cysteine molecules. L-cys has both negatively charged carboxylic group and a positively charged amine group, resulting in bridging between different particles. NAL-cys is a derivative of cysteine wherein an acetyl group is attached to the nitrogen atom thus shielding the positive charge on the amine group and therefore eliminating the bridging interaction mechanism. SRFA and YRNOM enhanced the stability of cit-AgNPs and increased the CCC value to higher counter ion concentrations. The concentration of SRFA (1-5 mg L-1) did not affect the CCC, whereas the increased concentration of YRNOM increased the CCC of cit-AgNPs to high Na+ concentrations likely clue to increased sorption of higher molecular weight compounds on the surface of cit-AgNPs. The outcome of this study suggests the importance of understanding the molecular properties of NOM (e.g. functional groups and molecular weight) in determining cit-AgNP environmental behaviors. (C) 2017 Elsevier B.V. All rights reserved.