After the 2009 United Nations Climate Change Conference, the South Korean government declared its intention to decrease its CO2 emissions by 2020. Ever since then, “green growth” has received much recognition, and has become one of the most important concepts both domestically and internationally.
Among the many diverse efforts to reduce CO2 emissions, membrane technology ㅡthe use of permeable membranes (a thin film-like material which acts as a selective barrierㅡ has become critical for “green growth”. In addition, its applications in the fields of environmental protection and energy engineering are limitless.
However, the usefulness of a membrane lies in its ability to achieve both permeability and selectivity. A membranes permeability and selectivity are negatively correlated, so normally both cannot be achieved at once.
To solve this problem, Young Moo Lee, Ph.D. (Professor and Chairman, Chemical Engineering) of Hanyang University (HYU) has found an innovative solution, called TR Membrane, which improves the performance of a membrane by more than 1,000 times, compared to traditional methods.
Lee is currently a distinguished professor of Hanyang and Chairman of WCU Department of Energy Engineering. He received his B.S. and M.S. at HYU in 1977 and 1979, and his Ph.D. at North Carolina State University in 1986. He has published over 260 papers in international journals. Moreover, he has been an Editor for the Journal of Membrane Science since 2004. His efforts studying polymer synthesis and its applications with membranes and biomaterials have been ongoing for more than 20 years.
The key to success with a membrane is determined by its cavity size. When separating mixtures, the cavity must have the optimal size. If the size is too big, permeability will be achieved while selectivity will be lost. When the size is too small, selectivity will be high while permeability will be low and the cost of separation would increase.
The size of O2 is 3.46 angstroms (A), N2 is 3.64A, CO2 is 3.3A, and CH4 is 3.3A. Therefore, in order to properly separate O2 from N2, the optimal cavity size would be around 3.5~3.6A. However, interestingly, traditional membranes consist of 2.8A cavities. Since an engine is required to pump the molecules, the smaller the size of the cavity the more energy it consumes. Thus, we optimized the size of cavity to be 3.5~3.6A and created the TR Membrane.
The method of changing the cavity size can be applied in numerous other fields. “Currently, our research is focused on gas separation, fuel cells, secondary batteries, desalination, thermo-stable fibers, low k dielectrics, H2 storage, and bio-medicine,” said Lee.
Lee’s TR Membrane is also in the process of being commercialized. By forming an agreement with Air Products and Chemicals, Inc., Lee had transferred his technology for a new porous polymer membrane used in CO2 separation. “While I am not sure about the exact date, I am expecting it to be on the market next year,” said Lee.
Greatly inspired to generate green energy, Lee’s future research will focus on generating electricity by using sea water. “In areas where rivers meet the sea, there is clear differentiation of NaCl, which provides an opportunity to generate electricity. By placing a turbine made of optimal cavity at the location, flow velocity would increase. Such velocity would eventually generate green energy,” said Lee.
Written by Jisoo Lee ([email protected])
