Viscosity Variations of Three-Component Mixtures Comprising an Alcohol,Various Common Groundwater Contaminants,and Water

Abstract

Abstract

This study investigates the variations in fluid viscosity as water was continuously added to a mixture containing methanol and a common groundwater liquid contaminant. Three different liquid contaminants were considered, namely benzene, toluene, and trichloroethylene. Each methanol-contaminant mixture (50%–50% by volume) was initially a single-phase solution, but partitioned into a two-phase liquid–liquid system after the total water content of the system reached a critical value. After the mixture partitioned into a two-phase system, fluid viscosities of each liquid phase were determined as more water was added to the system. A modified falling-ball viscometer was used to determine the viscosity of each mixture. Results from the viscosity experiments showed that in the single-phase region, the observed mixture viscosity increased with increasing total water content. In the two-phase region, the observed viscosity of the aqueous phase increased with increasing total water content, and then the viscosity decreased after reaching a maximum value. The observed viscosity of the nonaqueous phase decreased initially with increasing total water content, and then the viscosity remained relatively invariant as more water was added to the system. The viscosity variation in the aqueous phase was observed to be much more significant than the viscosity variation in the nonaqueous phase. The observed aqueous phase viscosity can range from 0.95 centipoise (pure water) to a maximum of approximately 1.7 centipoise. Finally, a viscosity model was used to compare the experimentally observed viscosity against the model-derived viscosities. In the single-phase region, modeling results showed that the average absolute deviation errors were fairly small for the three systems considered in this study (ranged between 2.35% and 5.12%). In the two-phase region, the errors were relatively higher in the aqueous phase (ranged between 7.78% and 10.63%) than in the nonaqueous phase (ranged between 3.33% and 6.20%).