Sorption of organophosphate esters by carbon nanotubes.
Sorption of organophosphate esters by carbon nanotubes.
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DOI：
10.1016/j.jhazmat.2014.03.030
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发表时间：
2014-05
影响因子：
13.6
通讯作者：
Wei Yan;Li Yan;J. Duan;C. Jing
中科院分区：
文献类型：
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作者：
Wei Yan;Li Yan;J. Duan;C. Jing
有机磷酸酯在碳纳米管上吸附的分子水平机理有助于我们进一步了解有机磷酸酯在环境中的归宿和迁移。本研究的目的是探讨OPEs在多壁碳纳米管（MWCNTs）、单壁碳纳米管（SWCNTs）及其氧化产物（O-MWCNTs和O-SWCNTs）上的吸附过程及其分子机理。吸附等温线结果表明，OPEs在碳纳米管上的亲合力主要由疏水性决定，而π-π电子给体-受体（EDA）相互作用对芳香族OPEs的吸附也起着重要作用.拉曼和红外光谱证实了这种π-π EDA相互作用可以限制单壁碳纳米管的径向振动，并影响OPE分子的形变振动γ（CH）带。利用非线性Dubininin-Ashtakhov模型估算的碳纳米管上的OPE表面覆盖率表明，碳纳米管上的含氧官能团可以通过氢键与水分子相互作用，导致有效吸附位点减少。此外，FTIR分析也证实了OPEs与SWCNTs表面OH基团之间存在着Brønsted酸碱相互作用。我们的研究结果应该提供OPE污染物在碳纳米管上的吸附机制的机械见解。
Insights from the molecular-level mechanism of sorption of organophosphate esters (OPEs) on carbon nanotubes (CNTs) can further our understanding of the fate and transport of OPEs in the environment. The motivation for our study was to explore the sorption process of OPEs on multi-walled CNTs (MWCNTs), single-walled CNTs (SWCNTs) and their oxidized counterparts (O-MWCNTs and O-SWCNTs), and its molecular mechanism over a wide concentration range. The sorption isotherm results revealed that the hydrophobicity of OPEs dominated their affinities on a given CNT and the π–π electron donor–acceptor (EDA) interaction also played an important role in the sorption of aromatic OPEs. This π–π EDA interaction, verified with Raman and FT-IR spectroscopy, could restrict the radial vibration of SWCNTs and affect the deformation vibration γ(CH) bands of OPE molecules. The OPE surface coverage on CNTs, estimated using the nonlinear Dubinin–Ashtakhov model, indicated that the oxygen-containing functional groups on CNTs could interact with water molecules by H-bonding, resulting in a decrease in effective sorption sites. In addition, FTIR analysis also confirmed the occurrence of Brønsted acid–base interactions between OPEs and surface OH groups of SWCNTs. Our results should provide mechanistic insights into the sorption mechanism of OPE contaminants on CNTs.