University of Kentucky CAER Home

CAER Seminars

New Membranes for CO2 Separation/Capture and Water Purification

Winston Ho
Ohio State University

October 3, 2014 at 10:00am
Ben Bandy Conference Center
UK Center for Applied Energy Research


This presentation covers two types of new membranes: (1) carbon dioxide-selective membranes for hydrogen purification for fuel cells and carbon capture from flue gas and (2) interfacially polymerized reverse osmosis membranes for water purification. We have synthesized CO2-selective membranes by incorporating amino groups into polymer networks. The membranes have shown high CO2 permeability and selectivity vs. hydrogen, carbon monoxide and nitrogen up to 180oC. We have elucidated the effect of amine steric hindrance in the solid membrane, showing significant enhancement for CO2 transport. Hydrogen sulfide permeates through the membrane much faster than CO2, allowing H2S removal in the treated synthesis gas before water-gas-shift (WGS) reaction.

Our initial experiments have shown a nearly complete removal of H2S from 50 ppm in synthesis gas to about 10 ppb in the hydrogen product. Using the membrane, we have obtained <10 ppm carbon monoxide in the hydrogen product in WGS membrane reactor experiments via CO2 removal. The data have been in good agreement with our modeling predictions. The membrane is being scaled up for commercialization. We will also discuss a new concept of zeolite/polymer composite membranes for CO2 capture from flue gas in coal-fired power plants for sequestration. On interfacially polymerized reverse osmosis membranes, the state-of-the-art membranes in the thin-film-composite (TFC) structure prepared by interfacial polymerization are reviewed and discussed.

Recent advances have been in high flux TFC interfacially polymerized membranes for increasing water productivity and decreasing energy consumption. We have synthesized high flux membranes by incorporating a hydrophilic additive in the aqueous amine solution during interfacial polymerization, resulting in increasing water flux significantly through an additional pathway for water transport while maintaining high salt rejection via charge repulsion. The membrane has shown 100% increase in water flux vs. the industry standard Film-Tec FT-30 membrane while maintaining a high NaCl rejection of about 99% for brackish water desalination. Initial scale-up of the membrane to commercial size has been successful. Also discussed is the fouling-resistant property of the synthesized membrane enhanced by physically coating a cross-linked polyethylene glycol layer on top of the thin film.

The Speaker:

W.S. Winston Ho
William G. Lowrie Department of Chemical and Biomolecular Engineering
Department of Materials Science and Engineering
The Ohio State University
Columbus, OH 43210-1178, USA

Dr. W.S. Winston Ho is University Scholar Professor in the William G. Lowrie Department of Chemical and Biomolecular Engineering and the Department of Materials Science and Engineering at the Ohio State University. Before teaching for 15 years, he had over 28 years of industrial R&D experience in membranes and separation processes, working for Allied Chemical, Xerox and Exxon, and serving as Senior Vice-President of Technology at Commodore Separation Technologies. He was elected to the National Academy of Engineering, USA in 2002 in recognition of his distinguished contributions to engineering, including the invention and commercialization of novel separation technologies and the development of new theoretical models for membrane separations. A New Jersey Inventor of the Year (1991), Dr. Ho holds more than 50 U.S. patents, generally with foreign counterparts, in membranes and separation processes.

He is Co-editor of Membrane Handbook, recipient of the Professional and Scholarly Publishing Award for the most outstanding engineering work in 1993. He received the 2006 Institute Award for Excellence in Industrial Gases Technology from the American Institute of Chemical Engineers (AIChE), and he was the 2007 recipient of Clarence G. Gerhold Award, from the AIChE Separations Division, one of the highest honors bestowed to those working on separations. He received the 2012 Lawrence B. Evans Award in Chemical Engineering Practice from AIChE. In 2014, he was elected to Academia Sinica, the highest form of academic recogniton in Taiwan.

He obtained his B.S. degree from National Taiwan University and his M.S. and Ph.D. degrees from the University of Illinois at Urbana-Champaign, all in Chemical Engineering. His research interests have included molecularly based membrane separations, fuel-cell fuel processing and membranes, water purification, reverse osmosis, separations with chemical reaction, facilitated transport, and transport phenomena in membranes.