469549 Tuning Separation Properties of Carbon Molecular Sieve Membranes with Diamine Dopants

Thursday, November 17, 2016: 10:18 AM
Plaza B (Hilton San Francisco Union Square)
Graham Wenz, School of Chemical and Biolmolecular Engineering, Georgia Institute of Technology, Atlanta, GA and William Koros, Chemical & Biomolecular Engineering, Georgia Institute of Technology, Atlanta, GA

Tuning Separation Properties of Carbon Molecular Sieve Membranes with Diamine Dopants

Graham B. Wenz and William J. Koros

Georgia Institute of Technology

Atlanta, GA 30332

Natural gas separations have become increasingly important as worldwide natural gas production has increased in the past decade. Common natural gas impurities, such as CO2, must be removed in order to protect equipment and meet pipeline specifications for transmission. Carbon molecular sieve (CMS) membranes, formed by high temperature pyrolysis of polymers under controlled conditions, have emerged as a new class of materials that can surpass the polymer “upper bound”. Similar to their glassy polymer precursors, CMS membranes display a physical aging phenomenon where productivity loss couples with a mild increase in selectivity when monitored over time. This behavior is thought to be cause by the relaxation of “free volume” trapped within the CMS structure during formation. This work outlines a new post-synthetic modification technique where CMS membranes are exposed to a solution containing PPM levels of amine dopants, with the original goal of preventing the “free volume” relaxation within CMS materials. While long term CO2 and CH4 permeation experiments showed aging-resistant membranes did not result, attractive performance resulted from the amine doped materials. The results of these experiments suggest amine doping as new technique to selectively modify the large pores present within the CMS microporous structure, resulting in increased size and shape based selectivity.


Extended Abstract: File Not Uploaded
See more of this Session: Membranes for Gas Separations III
See more of this Group/Topical: Separations Division