IONIC LIQUIDS FOR CELLULOSE PROCESSING AND CARBON CAPTURE: FROM FIRST-PRINCIPLES CALCULATIONS TO ATOMISTIC SIMULATIONS

Abstract

In the recent years, rapidly increasing energy demand and severe global warming are two major but contradictory challenges. Fossil fuels (coal, oil, and gas) are supplying nearly 85% of total energy demand and their combustion releases approximately 30 gigatons per year of CO2 into the atmosphere. In this perspective, there has been considerable interest in search of environmentally benign energy sources, and capturing CO2 to reduce global warming. As the most abundant, biodegradable, natural material on the earth, cellulose is considered to be a viable energy source to produce biofuels (a class of renewable fuels). However, cellulose is not readily dissolve/regenerate in common solvents due to its highly ordered structure and complex hydrogen-bonding network. In this context, emerging as a unique class of green solvents, ionic liquids (ILs) have been found as promising solvents for both cellulose processing (energy surrogate) and CO2 capture (counter global warming). In this thesis, firstly, we aim to unveil the cellulose dissolution/regeneration mechanism in ILs by both first-principle calculations and atomistic simulations. The simulation results reveal that cellulose-cellulose and cellulose-IL hydrogen-bonds are critical to govern cellulose dissolution/regeneration. In addition, water is found to be a promising anti-solvent for cellulose regeneration. Secondly, as novel porous materials, metal-organic framework supported IL membranes are proposed for CO2 capture. From simulations, the proposed membranes appear to exhibit better performance than many other counterparts, and microscopic insights into the separation mechanism are provided.