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首页> 外文期刊>Environmental Science & Technology >Aggregation Kinetics and Transport of Single-Walled Carbon Nanotubes at Low Surfactant Concentrations
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Aggregation Kinetics and Transport of Single-Walled Carbon Nanotubes at Low Surfactant Concentrations

机译：低表面活性剂浓度下单壁碳纳米管的聚集动力学和输运

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摘要

Little is known about how low levels of surfactants can affect the colloidal stability of single-walled carbon nanotubes (SWNTs) and how surfactant-wrapping of SWNTs can impact ecological exposures in aqueous systems. In this study, SWNTs were suspended in water with sodium dodecylsulfate(SDS) as a surface-active dispersing agent The effect of SDS concentration on SWNT suspension stability was investigated with time-resolved dynamic light scattering (TRDLS) initial aggregation studies utilizing both monovalent (Na~+) and divalent (Ca~(2+)) cations. The critical coagulation concentration (CCC) values increased with SDS concentration for the Na~+ treatments, but the Ca~(2+) treatments were less sensitive to SDS concentration changes. Longer term stability studies with SDS concentrations orders of magnitude below the SDS critical micelle concentration demonstrated that SWNTs remained suspended for over six weeks in a surface water. Transport studies in a freshwater sediment similarly showed a SDS concentration-dependent mobility of SDS-wrapped SWNTs in that SWNTs showed a relatively greater retention at lower SDS concentrations (0.001%-0.05% w/v) than at a higher SDS concentration (0.1%). It is hypothesized that the stability and mobility of SWNT suspensions is directly related to the surface coverage of SDS on the SWNT surface that simultaneously increases electrosteric repulsion and decreases surface chemical heterogeneity. Overall, these studies demonstrate that low levels of surfactant are effective in stabilizing and mobilizing SWNTs in environmental media.
机译：关于低含量的表面活性剂如何影响单壁碳纳米管（SWNTs）的胶体稳定性以及SWNTs的表面活性剂包裹如何影响水性体系的生态暴露，人们所知甚少。在这项研究中，SWNTs以十二烷基硫酸钠（SDS）作为表面活性分散剂悬浮在水中。通过时间分辨动态光散射（TRDLS）初始聚集研究，利用两种单价（ Na〜+）和二价（Ca〜（2+））阳离子。对于Na〜+处理，临界凝结浓度（CCC）值随SDS浓度的增加而增加，但是Ca〜（2+）处理对SDS浓度变化的敏感性较小。 SDS浓度比SDS临界胶束浓度低几个数量级的长期稳定性研究表明，SWNTs在地表水中的悬浮时间超过六周。在淡水沉积物中的迁移研究同样表明，SDS包裹的单壁碳纳米管的SDS浓度依赖于迁移率，因为单壁碳纳米管在较低的SDS浓度（0.001％-0.05％w / v）下显示出相对较高的保留率（在0.1％-0.05％w / v下）。 ）。假设SWNT悬浮液的稳定性和迁移率与SWDS表面上SDS的表面覆盖率直接相关，而SDS表面覆盖率会同时增加静电位阻并降低表面化学异质性。总体而言，这些研究表明，低含量的表面活性剂可有效稳定和动员环境介质中的单壁碳纳米管。

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  • 来源
    《Environmental Science & Technology》 |2012年第8期|p.4458-4465|共8页
  • 作者

    Dermont Bouchard; Wei Zhang; Tremaine Powell; U-sa Rattanaudompol;

  • 作者单位

    USEPA Office of Research and Development, National Exposure Research Laboratory, 960 College Station Road, Athens, Georgia 30605, United States;

    Department of Crop and Soil Sciences, Michigan State University, East Lansing, Michigan 48824, United States;

    USEPA Office of Research and Development, National Exposure Research Laboratory, 960 College Station Road, Athens, Georgia 30605, United States;

    Student Services Contractor, Athens, Georgia 3060S, United States;

  • 收录信息 美国《科学引文索引》(SCI);美国《工程索引》(EI);美国《生物学医学文摘》(MEDLINE);美国《化学文摘》(CA);
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