Solvent-membrane interactions in liquid Co₂ and organic solvent permeation through mesoporous & gamma - Alumina, titania, and zirconia membranes

Liquid CO₂ and organic solvent permeation was examined through a series of mesoporous ceramic membranes with different selective layers. In its liquid state, CO₂ acts as a non-polar organic solvent with comparable density and moderately lower viscosity, but with much lower surface tension. A custom high-pressure, cross-flow filtration system was used to investigate liquid CO₂ permeation in tubular membranes (Membralox™), while organic solvent permeation was examined using disk membranes (Sterlitech). Irreversible CO₂ adsorption, via reaction with surface OH to yield carbonate-like species, might have reduced the effective pore size. When water was present, a significant reduction in CO₂ flux and non-linear permeation behavior was observed. For the organic solvents, ethanol, butanol, and acetone exhibited transient permeation profiles, also consistent with a reduction in the effective pore size via adsorption. Adsorption was reversed with drying. Solvent-membrane interactions and their effect on non-aqueous solvent permeation (including hexane and toluene) were discussed. This is an abstract of a paper presented at the AIChE Annual Meeting and Fall Showcase (Cincinnati, OH 10/30/2005-11/4/2005).