(53d) Harvesting of Pure Water From Air and Combustion Exhaust Gas by Membrane Pervaporation

When there is scarcity in natural water resources, supply of pure, potable water becomes a problem for sustainable living and industrial development. On the other hand, presence of water in air is ubiquitous and water is also produced from combustion of biomass and hydrocarbon fuels. This presentation presents a brief review of various water recovery technologies reported in the literature and introduces a new membrane technology for production of water from humid air and/or combustion flue gas via a pervaporation process. In the pervaporation process, as a water-containing gas stream flows over a membrane surface, water vapor is selectively pulled out of the mixture into the another side of the membrane and is compressed to above its dew point by a vacuum pump so that the water vapor is condensed at ambient temperature and collected as liquid water. Important performance requirements of the membrane are 1) high water permeance, 2) high selectivity of water vapor over air, 3) robustness of the membrane, and 4) low cost. The thin flat sheet molecular sieve membrane recently developed in our research group will be presented to address these critical requirements for a practical membrane water production system. The new membrane provides very high water vapor permeance and a large window of operation conditions, such as temperature and water vapor content. Due to the water molecular specificity of the zeolite membrane material, the membrane pervaporation produces pure water in one-step without need of further purification.