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Gas filtration membrane

Q: We are looking for a gas filtration membrane. We want to separate VOCs from air. We have the choice among PDMS or PET membranes, some are more specific to polar compounds (eg PET) but have a slower response time, which is quite important for my process. What would be my best fit? Is there any thumb rule to help me going into the right direction to begin the tests?

A: Unfortunately, I don't have any suggestions. I've researched a couple of handbooks and most of them refer to carbon systems where the VOC's are adsorbed on carbon and then regenerated with steam. My search did show up one link which may be helpful. The Department of Energy has done some research into high pressure membrane separation of VOC's from Air. The link is: http://www.frtr.gov/matrix2/section4/4_62.html. I am not sure about the pressure drop required, but that may be prohibitive.

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