Metal-Organic Frameworks for Global Environmental Challenges

Over the past few decades, there has been a demand for improving nuclear waste administration due to a significant increase in the utilization of nuclear energy. The driving force for proper nuclear waste disposal is evident when considering past nuclear catastrophes—such as Chernobyl and Fukushima—where radionuclide contamination of large bodies of water sparked public concern. In order to manage such radioactive species, the emerging areas of radionuclide sequestration, storage, separation, and sensing must be addressed in the upcoming years. This dissertation presents a potential candidate for addressing these challenges, called metal-organic frameworks (MOFs). Due to their porosity, high surface area, and tunability, MOFs can be considered a particularly promising class of sorbent materials that can display an aptitude for sequestering radionuclides. The presented work highlights defect-controlled leaching kinetics of MOFs, which revealed a remarkable re-adsorption process using cerium cations as a surrogate for plutonium cations. Further, these studies developed a trend in the physicochemical properties of a series of heterometallic U/Th-containing frameworks as a function of metal ratio. Overall, the presented detailed structural analysis, kinetics, and thermochemical stability studies showcase MOFs as a viable nuclear wasteform material.