DESIGN STRATEGIES FOR METAL-ORGANIC FRAMEWORKS AS ACID GAS ADSORBENTS

Abstract

Design Strategies for Metal-Organic Frameworks as Acid Gas Adsorbents

Jayraj N. Joshi

316 Pages

Directed by Dr. Krista S. Walton Methods and heuristics for designing metal-organic framework (MOF)-based media towards acid gas adsorption applications were developed in this work. Relationships between MOF material properties and acid gas stability were first investigated through probing the impact of MOF defects, chemisorption site installation, and pelletization on various MOF substrates. Ligand functionalization was also leveraged to enhance sulfur dioxide and hydrogen sulfide uptake capabilities in various frameworks. Tested functional groups enabled both reversible and irreversible adsorption behavior—enhancing the breadth of applicability for evaluated framework adsorbents. Insoluble metal sources were found to enable facile MOF growth over supported and non-supported MOFs through novel production routes. The new methodology constitutes significant advancements in producing supported MOF media through simple, one-step procedures, instead of conventional multistep processes mandating high capital and operational costs. Additionally, resultant morphology, porosity, and crystalline orientation of non-supported products become adjustable; this control is importantly not possible with conventional metal precursors. Supported MIL-53(Al) MOF composites created from insoluble metal precursors are converted into MOF-derived oxide/carbon media, named MIL-53(Al)-oxide. Retrieved pillared alumina materials obtain multimodal pore accessibility, and enable acid gas chemisorption and localized MOF regeneration attributes. Overall, findings offer multiple routes for creating and employing MOF-based acid gas adsorbents in acid gas abatement applications.