• 2015 ~ present, Associate Professor, North Carolina State University
• 2011 ~ present, Adjunct Professor, Seoul National University
• 2016 Visiting Professor, KAIST
• 2009 ~ 2015, Assistant Professor, North Carolina State University
• 2007 ~ 2008, Postdoctoral Researcher, Bioenergy, National Renewable Energy Laboratory
• 2006 ~ 2007, Postdoctoral Researcher, Bioenergy, University of Tennessee at Knoxville
• 2006, Ph.D., Pulp and Paper, North Carolina State University
• 2001, M.S., Pulp and Paper, Seoul National University, Korea
• 1997, B.S., Forest Products, Seoul National University, Korea

Teaching

• PSE 355 Pulp and Paper Unit Processes I
• PSE 425 Bioenergy and Biomaterials Engineering
• WPS 760 Engineering Unit Operations for Biomass Conversion

Research Interests

His research is focused on the fundamental understanding of lignocellulosic biomass reactivity (changes in biomass chemistry/structure and their effects on conversion process) for both biochemical and thermochemical conversion processes into biofuels.

• Thermal pretreatment and its effect on fast pyrolysis. Thermal pretreatment of biomass such as torrefaction has a potential to be integrated with fast pyrolysis and gasification operation. His research is focused on the characterization of biomass chemistry/structure changes during thermal pretreatment and the evaluation of bio-oil quality when torrefied biomass is used.
• Cellulose crystalline structure and its allomorphs. Fundamental understanding of cellulose crystalline structure is critical for many applications such as paper, textiles, chemicals, and bioenergy. Recently we have applied new technology (sum-frequency-generation vibration spectroscopy) together with x-ray diffraction and solid-state NMR to elucidate its structure. SFG spectroscopy can selectively detect cellulose crystalline structure without interference from hemicellulose and lignin.
• Biomass post-treatment and enzymatic hydrolysis. Inefficient enzymatic hydrolysis of biomass is largely due to the recalcitrant nature of lignocellulosic biomass. This study focuses on identifying the physico-chemical properties of biomass responsible for low conversion efficiency and developing post-treatment operations to overcome recalcitrant issues.

Publications

• Alkaline extraction and characterization of residual hemicellulose in dissolving pulp (2019)
• Impact of oxidative carbonization on structure development of loblolly pine-derived biochar investigated by nuclear magnetic resonance spectroscopy and X-ray photoelectron spectroscopy (2019)
• Testing of anisole and methyl acetate as additives to diesel and biodiesel fuels in a compression ignition engine (2019)
• The influence of lignin content and structure on hemicellulose alkaline extraction for non-wood and hardwood lignocellulosic biomass (2019)
• Two-stage autohydrolysis and mechanical treatment to maximize sugar recovery from sweet sorghum bagasse (2019)
• Adsorption isotherm, kinetic modeling and mechanism of tetracycline on Pinus taeda-derived activated biochar (2018)
• Blended Feedstocks for Thermochemical Conversion: Biomass Characterization and Bio-Oil Production From Switchgrass-Pine Residues Blends (2018)
• Effect of Mechanical Refining Energy on the Enzymatic Digestibility of Lignocellulosic Biomass (2018)
• Graphitization Behavior of Loblolly Pine Wood Investigated by in Situ High Temperature X-ray Diffraction (2018)
• Impacts of feedstock properties on the process economics of fast-pyrolysis biorefineries (2018)

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