Kirchon, Angelo Anthony (2020-11). Developing Commercially Scalable Iron and Titanium Metal-Organic Frameworks for Gas Storage and Water Purification. Doctoral Dissertation.
Thesis
Since their discovery in the late 1990s, Metal-Organic Frameworks (MOFs) have turned into one of the fastest growing classes of materials studied in the chemical literature. MOFs have shown promise in applications such as gas storage, chemical separations, chemical sensing, catalysis, and even drug delivery. Their wide range of potential applications can be attributed to their ultra-high surface area, high crystallinity and tunable physical and chemical properties. However, the potential applications of MOFs have been slow to develop into viable and sustainable products at the commercial or industrial level. Chapter I of this dissertation discusses the background of Metal-Organic Frameworks (MOFs), the current limitations of MOFs that prevent wide spread commercial production such as stability, processing cost, and synthesis cost as well as how the research performed aimed to address these challenges. In Chapter II details a method that was developed in order to synthesize a Hierarchally Porous (HP) variant of a commercially available MOF named PCN-250(Fe3O). The method developed utilizes the addition of fatty acids during MOF synthesis in order to induce and engineer hierarchal porosity within PCN-250(Fe3O). The resulting Hierarchally Porous MOFs (HP-MOF) exhibited completely different mesoporosity in size, volume, and position. Furthermore, the PCN-250(C9-1.4M) material obtained adsorbs/removes 100% of Methylene Blue, a common organic dye, from aqueous solution, as compared to the microporous variant of PCN-250(Fe3O), which only removes 31% Chapter III builds on the use of PCN-250(Fe3O) as a material for removing organic dyes from water, but utilizes PCN-250(Fe3O) as a catalyst, not just an adsorbent. PCN-250 was reported to be a successful and recyclable Fenton and photo-Fenton catalyst that degrades 100% of Methylene Blue. Overall, 4 different variants of PCN-250 were synthesized and named PCN-250(Fe3O), PCN-250(Fe2Ni), PCN-250(Fe2Co) and PCN-250(Fe2Mn). The catalytic degradation efficiency for both Fenton and photo-Fenton reactions was improved by the isomorphic substitution of Mn and Co for Fe, but inhibited by the incorporation of Ni. Chapter IV details the development of a photo-catalytic system for the degradation of Per/Poly-Fluorinated Alkyl Substances (PFASs) using a commercially scalable Ti-Based MOF. With the developed photo-catalytic system, the concentration of Perfluorooctanoic acid (PFOA) can be reduced by 49% and with a 21.1% fluoride mineralization efficiency in 24 hours. Overall, this work has shown the ability to successfully design Metal-Organic Frameworks based photo-catalytic platforms for chemically reducing (degrading) Per- and polyfluoroalkyl substances (PFAS) in water and is to the best of our knowledge the first successful example of using MOFs for PFAS degradation. Chapter V, details the development of a novel MOF processing method that maximizes the surface area while minimizing cost. The method is a suspension-based processing 3 step method that maximizes the porosity of MOFs by more effectively solubilizing unreacted starting materials and more importantly, removing area of low crystallinity from the surface of MOF particles. In the last chapter, Chapter VI, a summary of the current work is given along with my thoughts and outlooks on future of MOFs.
