Sorption of Phenyl Urea Herbicides to Black Carbon
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- 作者：Anna Sobek ; Nadine Stamm ; Thomas D. Bucheli
- 刊名：Environmental Science & Technology
- 出版年：2009
- 出版时间：November 1, 2009
- 年：2009
- 卷：43
- 期：21
- 页码：8147-8152
- 全文大小：217K
- 年卷期：v.43,no.21(November 1, 2009)
- ISSN：1520-5851
文摘
In this work, we developed a dialysis technique to determine black carbon (BC; diesel soot)-water distribution coefficients (KBC) of nine phenyl urea herbicides (PUHs). The KBC at 1 μg/L ranged over 2 orders of magnitude, with diuron displaying the highest log KBC of 4.5. The KBC were 20−170 times higher than corresponding estimated partitioning coefficients to organic carbon (KOC). This is consistent with earlier findings for more hydrophobic compounds. There was a linear increase in log KBC with decreasing thermodynamic difference between the geometrically optimized and planar molecule conformation (ΔEplanar). Hence, previous observations of enhanced BC adsorption of planar compounds (e.g., non-ortho-polychlorinated biphenyls) were confirmed also for the polar PUHs. Further, the data suggested indirectly that for molecules with several different functional groups (such as the PUHs), specific electron donor and acceptor interactions may be of more relevance for the adsorption to BC than the ability of the molecule to undergo dispersive van der Waals interactions. Sorption coefficients estimated from poly parameter linear solvation energy relationships (pp-LSER) based on data for activated carbon were 1−1.5 log units higher than the experimental data for diesel soot. This illustrates the complexity in applying models developed for one BC form to another, and calls for more data on soot-water distribution descriptors.