Separation of a 2-Propanol/n-Heptane Mixture by Liquid Membrane Perstraction

The effectiveness of perstraction separation of a 2 vol % 2-propanol-n-heptane mixture using dodecane as the strip liquid was studied using a hollow fiber contained liquid membrane permeator (HFCLMP). The liquid membranes used were pure water and 3 wt % water in sulfolane. Both liquid membranes yielded similar mass-transfer coefficients and 2-propanol removal rates. Pure water, however, exhibited 3 times higher selectivity for 2-propanol than 3 wt % water in sulfolane. Selectivities of 2-propanol over n-heptane as high as 447 were experimentally obtained. The observed fluxes and selectivities at 25 °C are close to those obtained in prevaporation of a 10% 2-propanol-n-hexane mixture through cellulose ester films at 60 °C. A first-order mathematical model was developed using partition coefficients that are functions of solute concentration, and it predicts the observed behavior of the two systems relatively well.