Aqueous ethanol permeation across Sterlitech flat sheet aquaporin membranes

Abstract

Aquaporin (Aqp) embedded membranes have become a topic of recent research due to the superior selectivity of Aqp to water and its acceptable flux. Most researchers have utilized Aqp membranes for water purification purposes such as reverse and forward osmosis desalination of sea and brackish water and wastewater treatment. This paper investigated the permeation of aqueous ethanol across commercial aquaporin membranes for possible applications in ethanol dehydration in the process and biofuel refining industries. The study revealed that rather than being selectively rejected, ethanol was able to diffuse through the membrane with minimal changes in composition from feed to permeate, even at low feed concentrations of ethanol. The total flux across the membranes were shown to average 3.86 liters/m2h (LMH). The presence of ethanol increased the relative rate of water transport across the membrane. When comparing total flux of pure water to aqueous ethanol solutions, the flux was higher for solutions containing any ethanol.