Membrane separation technology has been designed by U.S. Department of Energy (DOE) to treat vapor streams that contain dilute concentrations of volatile organic compounds (VOCs). The technology involves the preferential transport of organic vapors through a nonporous gas membrane. Membranes are typically made of a polymer, and are designed for each application. In the DOE system, the vapors are then condensed, and a liquid solvent is recovered.
Limitations and Concerns
Membranes have difficulty handling fluctuations in VOC concentrations.
Separation technology is not cost effective when dealing with several different contaminants at once.
The targeted contaminants for membrane separation technology are VOCs in vapor streams exiting treatment systems.
Technology Development Status
Membrane separation has commercial applications in process engineering. It is relatively new for use in the remediation field, and it is a pilot project.
Other Resources and Demonstrations
See http://www.clu-in.org/download/remed/EPA542R05028.pdf, Off-Gas Treatment Technologies for Soil Vapor Extraction Systems: State of the Practice, EPA, 2006, Section 6.3 for Membrane Separation.