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Zeolite Membrane Research

Zeolite membranes can separate mixtures that are difficult to separate because of the molecules have similar physical or chemical properties (boiling points, molecular weight, etc.) or because they form azeotropes. Membranes with molecular-sized zeolite pores have separation selectivities that are greater than 1000 for some mixtures. Our publications on zeolite membranes have been extensively cited. Three of our papers published in Industrial and Engineering Chemistry Research were 11th, 12th, and 63rd on the list of the 95 most-cited in that journal in 2003. Also, three of our papers were 23rd, 31st, and 35th most cited papers published in the Journal of Membrane Science (as of November 2004) during its 20 years of publication.

Applications

Energy

• Hydrogen separations for fuel cells
• Hydrocarbon isomer separation
• Carbon dioxide/methane separation for natural gas wells

Environmental

• Organic removal from water
• Carbon dioxide removal

Research to understand and improve separations

Prepare and characterize zeolite membrane

• SAPO-34, Beta, B-ZSM-5, SSZ-13, ZSM-11, X, Y
• Modify membranes

Understand membrane transport

• Transient gas permeation
• Transient isotope pervaporation
• Mathematical modeling
• Adsorption of mixtures

Zeolites are crystalline structures with pores of molecular dimensions and narrow pore size distributions. These properties plus their high thermal, chemical, and mechanical stabilities make them ideal membranes. Zeolite structures are formed by combining tetrahedra that consist of a central cation surrounded by four oxygen atoms. They are usually aluminosilicates, but the central cation can be Si, Al, P, Ga, Ge, B, etc.

This research is currently supported by the National Science Foundation, the Department of Energy, Shell Global Solutions, Sandia National Laboratories, and the American Chemical Society-Petroleum Research Fund.