Quantitative High-Resolution Mapping of Phenanthrene Sorption to Black Carbon Particles

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• 作者：Martin Obst ; Peter Grathwohl ; Andreas Kappler ; Oliver Eibl ; Nicola Peranio ; Tilman Gocht
• 刊名：Environmental Science & Technology
• 出版年：2011
• 出版时间：September 1, 2011
• 年：2011
• 卷：45
• 期：17
• 页码：7314-7322
• 全文大小：1039K
• 年卷期：v.45,no.17(September 1, 2011)
• ISSN：1520-5851

文摘

Sorption of hydrophobic organic contaminants such as polycyclic aromatic hydrocarbons (PAHs) to black carbon (BC) particles has been the focus of numerous studies. Conclusions on sorption mechanisms of PAH on BC were mostly derived from studies of sorption isotherms and sorption kinetics, which are based on batch experiments. However, mechanistic modeling approaches consider processes at the subparticle scale, some including transport within the pore-space or different spatial pore-domains. Direct evidence based on analytical techniques operating at the submicrometer scale for the location of sorption sites and the adsorbed species is lacking. In this work, we identified, quantified, and mapped the sorption of PAHs on different BC particles (activated carbon, charcoal and diesel soot) on a 25鈥?00 nm scale using scanning transmission X-ray microscopy (STXM). In addition, we visualized the pore structure of the particles by transmission electron microscopy (TEM) on the 1鈥?0 nm-scale. The combination of the chemical information from STXM with the physical information from TEM revealed that phenanthrene accumulates in the interconnected pore-system along primary 鈥渃racks鈥?in the particles, confirming an adsorption mechanism.