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Process for restoring membrane permeation properties

United States Patent

*** EXPIRED ***
May 20, 1997
View the Complete Patent at the US Patent & Trademark Office
A process for restoring the selectivity of high-flee-volume, glassy polymer membranes for condensable components over less-condensable components or non-condensable components of a gas mixture. The process involves exposing the membrane to suitable sorbent vapor, such as propane or butane, thereby reopening the microvoids that make up the free volume. The selectivity of an aged membrane may be restored to 70-100% of its original value. The selectivity of a membrane which is known to age over time can also be maintained by keeping the membrane in a vapor environment when it is not in use.
Pinnau; Ingo (Palo Alto, CA), Toy; Lora G. (San Francisco, CA), Casillas; Carlos G. (San Jose, CA)
Membrane Technology and Research, Inc. (Menlo Park, CA)
08/ 448,652
May 24, 1995
This invention was made in part with Government support under Contract Numbers DE-FG03-90ER81066 and DE-FG03-94ER81811, awarded by the Department of Energy. The Government has certain rights in this invention.