Saudi Cultural Missions Theses & Dissertations
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Item Restricted Incorportation of Caesium into Potassium-Silicate Geopolymers(University of Sheffield, 2024-01-23) Alkhateeb, Khaled; Walkley, BrantThis dissertation explores the process of incorporating caesium into potassium silicate activated geopolymers providing insights into its effects. Geopolymers, known for their potential in construction serve as the context for examining the challenge of integrating caesium. The focus is on understanding the implications of caesium’s radius within geopolymerisation chemistry and kinetics. To investigate the geopolymer matrix, these two powerful analytical techniques are utilized; isothermal conduction calorimetry (ICC) and Fourier transform infrared (FTIR) spectroscopy. These tools enabled the team to uncover the relationship between caesium and the geopolymerisation process. They clarify how caesium interacts with the structure and evolution of geopolymers. The study also examines the characterization of geopolymers with an emphasis on how alkaline earth cations (Ca2+ and Sr2+) influence their molecular configurations and properties. Advanced analytical methods such as X ray Diffraction (XRD) Solid state Nuclear Magnetic Resonance (NMR) and Fourier Transform Infrared Spectroscopy (FTIR), and Isothermal Conduction Calorimetry (ICC) were employed to analyse geopolymers consisting primarily of metakaolin and alkali activators. XRD analysis revealed that the geopolymer structure was amorphous. Subtle changes were observed due to the presence of alkaline earth cations. Various solid state NMR techniques, including 29Si MAS, 1H 29Si CP MAS, 27Al MAS and 23 Na MAS NMR revealed changes, in the Si environments caused by the presence of Ca2+ and Sr2+ ions. These changes indicated alterations in polymerization states and connectivity. The analysis of aluminium species and local environment interactions was carried out using 27Al MAS and 23Na MAS NMR techniques, which were supported by absorption bands identified through FTIR spectroscopy. This combined approach provided insights into how composition molecular configuration and cation influence affect geopolymers. It also offered promising avenues for customizing these materials for construction and future advancements in the field. In summary this thorough review represents an understanding of the relationship between caesium and geopolymers. Its significance extends beyond academia as it aligns with efforts to improve containment and storage methods for waste. This signifies a step towards solutions, in construction, environmental preservation and nuclear energy safety.28 0