Concentration of aqueous ethanol solutions by porous poly(dimethylsiloxane) membranes during temperature-difference controlling evapomeation

摘要

In order to obtain higher membrane performance in the concentration of aqueous ethanol solutions,a porous poly(dimethylsiloxane) (PDMS) membrane was applied to the temperature-difference controlling evapomeation (TDEV) method.Characteristics of permeation and separation for aqueous ethanol solutions through a porous PDMS membrane during TDEV under various conditions are discussed from the viewpoint of membrane structure.When the characteristics of permeation and separation of a porous PDMS membrane were compared with those of a dense PDMS membrane,the ethanol/water selectivity of these membranes was almost equal,but the permeation rate of a porous PDMS membrane was higher by three orders of magnitude than that of a dense PDMS membrane.When the temperature of the feed solution was kept constant at 40 deg C and the the temperature of the membrane surroundings was changed in TDEV,with dropping temperature of the membrane surroundings the permeation rate decreased but the ethanol/water selectivity increased for an aqueous solution of 10 wt% ethanol through a porous PDMS membrane.