Permeation of vapor and pervaporation of organic vapors through polymer membranes

Permeability by vapor through polymer membrane were discussed as to its measurement, properties and application for processes using membranes. The permeabilities of vapor from water and vapor from organic substances through a rubber membrane and cellulosic polymer membranes were measured by a new method using a differential transformer. The resulting permeabilities were compared with that by other method of measurement. The feature of permeability by vapor for organic vapors is the dependency on partial pressure and temperature. The correlation equations for permeability by vapor were presented by taking into consideration diffusion and sorption through polymer. The measured permeability by vapor and flow models were applied to the membrane filter processes; the volatile organic vapors filtration using silicone rubber hollow-fiber membrane module, the filtration of a trace organic solute from water by pervaporation, separation of ethanol/water by pervaporation, the membrane degassing process by dense membrane and the membrane heat-exchange process using latent heat of vaporization through membrane. These processes were analyzed by similar methods, the dry layer model for pervaporation. This analysis was extended to a swollen-dry layer model. The pervaporation experiments of ethanol/water through a highly swollen hydrophilic polymer membrane were compared with this model.