Zoe R. Boehman, Austin G. Dias, Luke F. Flottman, Katelyn Leigh Petrycki
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Liquid-liquid extraction (LLE) is a separation technique that transfers a solute between two immiscible solvents. The separation of ethanol through LLE is prevalent in biomass purification, gas additives, and the food safety industries. This research aims to generate a new experiment involving LLE processes in the Unit Operations laboratory at UD. Castor oil served as the organic phase to separate ethanol from water due to their differences in miscibility. The effectiveness of castor oil was measured using a mixer-settler unit (~ 2 L) with a 5 wt.% ethanol/water mixture. Volumetric ratios of castor oil to ethanol, such as 6:4, 5:5, and 7:3, were pumped, mixed, and run in the mixer-settler apparatus. At various time intervals, samples were taken from oil and aqueous phases, centrifuged, and analyzed using gas chromatography or a densitometer. Extracted samples did not reach equilibrium, and a discrepancy existed between the experimental results and the theoretical model found using a ternary diagram. Additional trials involving an extra settling chamber showed that longer mixing-settling times led to enhanced ethanol extraction. Centrifugation, however, was needed to separate the two phases. A second organic solvent, Multitherm heat transfer fluid, separates from the aqueous phase faster than castor oil. We performed small-scale experiments (10 mL) at different ratios of Multitherm to 5 wt.% ethanol/water solutions, such as 1:1, 6:4, 7:3, 8:2, 9:1, and 2:8. The 2:8 mixture showed enhanced separation based on ethanol concentration in the aqueous phase. Conversely, 2:8 mixtures of 5 wt.% ethanol/oil solution to water were mixed and analyzed. Unfortunately, ethanol stayed immiscible with the oil, and the water phase only removed 1.2 wt.% ethanol. The new mixture was targeted for ease of phase separation when running the mixer-settler unit, and the preliminary trials allowed for pursuing experimentation for a closed system mixer-settler unit.
Michael J. Elsass, Erick Vasquez
Primary Advisor's Department
Chemical and Materials Engineering
Stander Symposium project, School of Engineering
United Nations Sustainable Development Goals
Responsible Consumption and Production
"Design and Validation of a Liquid-Liquid Extraction Unit Operation Experiment" (2022). Stander Symposium Projects. 2723.