Molecular and Extended Framework Pyrene Materials for CO2 Separations in Humid Environments

To separate CO2 efficiently from industrial flue gas streams, it is vital that humidity be considered. If the adsorption of H2O is not minimised, the presence of humidity in gas streams often out-competes CO2 adsorption as well as increasing the regeneration cost of the material. In this thesis a series of materials were synthesised using pyrene systems, which was computationally identified as an effective and selective CO2 adsorbing motif. Chapter 1 This chapter introduces the primary concepts explored in this thesis, focussing on the underlying science of climate change, the role of carbon capture and storage (CCS) in combatting this approaching disaster and the challenges involved, the various classes of porous material and their application to CCS and, finally, the design of porous materials for this application. Chapter 2 This chapter outlines the experimental and theoretical methods used in this work, paying particular attention to the underlying theory of gas sorption and dynamic column breakthrough (DCB) analyses. Chapter 3 This chapter describes pyrene-based hydrogen bonded organic frameworks (HOFs), rationally designed using Density Functional Theory (DFT) and Crystal Structure Prediction (CSP). Gas sorption experiments were used to examine the adsorption of CO2 and water of these materials. Further analysis using dynamic column breakthrough methods was carried out to explore performance in mixed gas environments. The materials were then structured into fibers with cellulose acetate to explore their behaviour for scale up. Finally, two other HOF variants were briefly explored to ascertain the effects of different functional groups on gas sorption capacities. Chapter 4 This chapter explored covalent organic framework (COF) materials containing the tetrakis-(o-methylphenyl)-pyrene linker and how increasing substitution of methyl groups affects CO2 and water capacities. Chapter 5 This chapter explored aluminium and zirconium metal organic frameworks (MOFs) constructed using MeTBAP and HOTBAP molecules explored in Chapter 3. These materials were isostructural between metals and enabled the analysis of how the inclusion of methyl groups affect gas uptake beyond the structural changes observed in Chapters 3 and 4.