Review on “Membranes for Ethanol-Water Separation”

Abstract

Bioethanol fuel produced directly from the renewable biomass is one of the truly important energy developments in Thailand. Typically, the ethanol concentration after fermentation is quite low. Normally, ethanol, as called anhydrous ethanol or absolute ethanol used for fuel energy, is required 99.5% purity or concentration. It is necessary to use energy-effective separation method for concentrating ethanol up to the fuel level. There are several techniques used to purify ethanol such as distillation, membrane technology and molecular sieve separation. Recently, the less energyintensive technique of pervaporation is found to be a promising method for producing high-purity ethanol, but the overall economic feasibility is dependent upon the membrane. Thus, in this review, various membranes reported in literature are discussed and compared as to their advantages, disadvantages, and separation performance via the pervaporation process. It is found that different membranes provide different performances and advantages in ethanol separation. Other parameters governing the separation performance, such as temperature, ethanol concentration, membrane production method, and production cost, are also included.