Influence of Organic Acid and Organic Base Interactions on Interfacial Properties in NAPL-Water Systems

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• 作者：Hsin-Lan Hsu ; Avery H. Demond
• 刊名：Environmental Science & Technology
• 出版年：2007
• 出版时间：February 1, 2007
• 年：2007
• 卷：41
• 期：3
• 页码：897 - 902
• 全文大小：127K
• 年卷期：v.41,no.3(February 1, 2007)
• ISSN：1520-5851

文摘

Interfacial properties play an important role in determiningthe transport and distribution of waste nonaqueousphase liquids (NAPLs) in groundwater. To develop a betterunderstanding of the solute interactions governing theinterfacial properties of waste NAPLs, this study examinedthe interfacial tension and contact angle of a tetrachloroethylene/water/quartz system containing octanoic acidand dodecylamine as a function of pH. The results showedthat interactions between these solutes affected thesystem's interfacial properties significantly, producing apositive synergism. For example, octanoic acid, which byitself does not affect wettability, could reverse the wettabilityof quartz in the presence of dodecylamine. The significantreduction in interfacial tension and increase in contactangle around neutral pH was, based on the results ofspeciation modeling, attributed to the formation of a complexcomposed of the protonated organic base and deprotonatedorganic acid, whose formation also peaks around neutralpH. Thus, measures of the content of only one class ofcompounds, such as the base number, are inadequatedescriptors of a NAPL's ability to alter wettability.