Ph.D. Yale University. Chemical Engineering. 1971.
M.A. Yale University. Chemical Engineering. 1968.
B.S. National Taiwan University. Chemical Engineering. 1964.
Adsorption. This research is focused on gas adsorption for the purpose of separation and purification. All fundamental aspects of adsorption are being studied: 1) Gas-solid equilibria, 2) Diffusion (pore diffusion, surface diffusion, diffusion in zeolites), 3) Dynamics in fixed-bed adsorbers, 4) Cyclic adsorption/desorption processes with particular interest in pressure swing adsorption, and 5) the hysteresis phenomena. We are also exploring field-assisted adsorption and desorption. We have had success in ultrasound assisted desorption of strongly adsorbed molecules, such as phenols, on activated carbon and resins. We have found that ultrasound could replace chemical regeneration.
New Adsorbent Materials. We are exploring the possibility of synthesizing new sorbents by exploiting weak and reversible chemical bonds. Zeolites containing mixed cations including Ag are being studied as superior N2-selective sorbents. An understanding for the bonding as well as design of the sorbents is being obtained through molecular orbital calculations. We are developing new sorbent materials which are tailored to provide desired diffusivities for different gas molecules. With these sorbents, it will be possible to accomplish separations of gas mixtures by kinetic separation. This is our first attempt to replace solvent extraction with dry adsorption by taking the approach of immobilizing extractants on solid substrates.
We have been studying new sorbents for the purpose of removing sulfur compounds from gasoline and diesel fuels. The current level of sulfur in gasoline and diesel is about 350 ppm, which must be lowered to below 30 ppm for gasoline and 15 ppm for diesel in 2006 under the federal law. Adsorption appears to be the most economical way (and possibly the only feasible way) to accomplish this difficult task. For hydrogen storage materials our approach is to use hydrogen spillover via an added catalyst in nanostructured carbons. We are working on sorbents that will meet the DOE target of 6.5% wt% storage at room temperature, and also to obtain a basic understanding of the hydrogen spillover mechanism.
Environmental Catalysis. The selective catalytic reduction (SCR) of NO with ammonia is a process that has been commercialized in the U.S. for power plant emission control. We are studying new catalysts for this reaction. We have had success with pillared clays and ion-exchanged pillared clays for these applications.
Gas-Carbon Reactions. Research is being conducted on the kinetics and mechanisms of gas-carbon reactions, both uncatalyzed and catalyzed. These reactions are important in coal conversion, metallurgy, catalyst regeneration, and a number of chemical processes. We are focusing on the C-NO reaction which is of importance in environmental control. Our approach has been to study rates on well defined active sites of carbon using single crystal graphite. A new surface oxygen intermediate was proposed with which a unified mechanism can be applied to all gas-carbon reactions involving oxygen atoms.
Carbon Nanotubes and Hydrogen Storage. We are studying carbon nanotubes and graphite nanofibers (GNF) as unique sorbents. We have already found that multiwall nanotubes are the best selective sorbents for dioxins and also for NO. We are sorting out the controversies on issues of hydrogen storage in carbon nanotubes.
L. F. Wang and R. T. Yang, “Significantly Increased CO2 Adsorption Performance of Nanostructured Templated Carbon by Tuning Surface Area and Nitrogen Doping,” J. Phys. Chem. C., 116, 1099 (2012).
L. F. Wang, B. D. Sun, F. H. Yang and R. T. Yang, “ Effects of Aromatics on Desulfurization of Liquid Fuels by π-complexation and Carbon Adsorbents,” Chem. Eng. Sci., 73, 208 (2012).
L. F. Wang, N. R. Stuckert, H. Chen and R. T. Yang “Effects of Pt Particle Size on Hydrogen Spillover Storage on Pt-doped Metal-Organic Framework IRMOF-8,” J. Phys. Chem. C., 115, 4793 (2011).
L. F. Wang and R. T. Yang, “Molecular Hydrogen and Spiltover Hydrogen Storage on High Surface Area Carbon Sorbents,” Carbon (Thrower Festchrift), in press.
L. F. Wang and R. T. Yang, “Increasing Selective CO2 Adsorption on Amine-grafted SBA-15 by Increasing Silanol Density,” J. Phys. Chem. C, 115, 21264 (2011).
N. R. Stuckert and R. T. Yang, “Atmospheric CO2 Capture and Simultaneous Concentration using Zeolites and Amine-grafted SBA-15,” Environ. Sci. Tech. 45, 10257 (2011).
J. H. Li, H. Z. Chang, L. Ma, J. M. Hao and R. T. Yang, “Low-temperature Selective Catalytic Reduction of NO with NH3 over Metal Oxide and Zeolite Catalysts – A Review,” Catal. Today, 175(1), 147 (2011).