Molecular Simulations for CO2 Capture in Metal-Organic Frameworks

Abstract

Metal-organic frameworks (MOFs) as a special class of hybrid materials have received considerable interest in the last decade. The large surface area, high porosity, and tunable structures place them at the frontier for a wide range of potential applications such as gas storage, separation, catalysis and drug delivery. In this thesis, molecular simulations have been performed for CO2 capture in different MOFs with unique functionalities. Firstly, CO2 adsorption was investigated in mesoporous MIL-101 that is one of the most porous materials reported to date. The coordinated water molecules were found to play an interesting role in CO2 adsorption. Secondly, the adsorption and separation of CO2/CH4, as well as methanol/water, in highly hydrophobic Zn(BDC)(TED)0.5 are examined. Water was found to have a marginal effect on CO2/CH4 separation, thus pre-water treatment is not required prior to separation. Thirdly, CO2 capture was investigated in a bio-MOF (bio-MOF-11). The predicted high selectivities of CO2/H2 and CO2/N2 mixtures suggest that bio-MOF-11 may be interesting for pre- and post-combustion CO2 capture. Fourthly, adsorption and separation of CO2/H2 were simulated in cation-exchanged rho zeolite-like MOF (rho-ZMOF) (Cs+, Rb+, K+, Na+, Ca2+, Mg2+ and Al3+). This study shows that the performance of ionic rho-ZMOF can be tailor by cations. Finally, a new composite of ionic liquid (IL) [BMIM][PF6] supported on IRMOF-1 was proposed for CO2 capture. The selectivity of CO2/N2 increases with increasing IL ratio in the composite.