Influence of Wettability on the Recovery of NAPLs from Alluvium

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• 作者：Varadarajan Dwarakanath ; Richard E. Jackson ; and Gary A. Pope
• 刊名：Environmental Science & Technology
• 出版年：2002
• 出版时间：January 15, 2002
• 年：2002
• 卷：36
• 期：2
• 页码：227 - 231
• 全文大小：61K
• 年卷期：v.36,no.2(January 15, 2002)
• ISSN：1520-5851

文摘

The physicochemical characteristics of five nonaqueousphase liquids (NAPLs) recovered from contaminated alluvialaquifers are presented. The five include two chlorinateddegreasing solvents, one chlorinated dry-cleaning solventand two weathered fuel hydrocarbons. In addition todensity, viscosity, and interfacial tensions, the equivalentalkane carbon number (EACN), spreading coefficients andAmott-Harvey and USBM wettability indices with respectto alluvial aquifer materials are used as a means tocharacterize three of these NAPLs. Experimentally measuredspreading coefficients of four of these NAPLs illustratethat field NAPLs can have positive initial spreadingcoefficients. Furthermore, capillary desaturation curvesfor two NAPLs with alluvial aquifer material collected fromthe NAPL zone are presented as an additional andimportant means to infer the practical implications of thewetting characteristics on the efficacy of NAPL recovery.The results from the wettability and capillary desaturationexperiments show that these NAPLs are mixed-wet to oil-wet when measured in the alluvium from their respectivefield sites. Furthermore, these results indicate that thedisplacement of NAPLs from soils by water is more difficultfor mixed-wet or oil-wet soils than it is for water-wet orweakly water-wet soils. Finally experimental data indicatethat adding anionic surfactants to the water shifts thewettability toward water-wet and makes the NAPL easierto displace and recover.