The physicochemical similarities of hydrogen isotopes have made their separation a challenging task. Conventional methods such as cryogenic distillation, Girdler sulfide process, chromatography, and thermal cycling absorption have low separation factors and are energy-intensive. To overcome these limitations, research has focused on kinetic quantum sieving (KQS) and chemical affinity quantum sieving (CAQS) effects for selective separation of hydrogen isotopes. Porous materials such as metal-organic frameworks (MOF), covalent organic frameworks (COF), zeolites, carbon, and organic cages have been studied for hydrogen separation. In this study, we focus the enhancement for CAQS to provide the cations due to the chemical affinity between hydrogen isotope and unsaturated sites by cations in zeolite beads. Cation exchanged zeolite beads was synthesized with cobalt, copper, nickel, iron and silver in zeolite 4A beads. Synthesized cation exchanged zeolite was analyzed for the surface area and pore size in N2 and adsorption behaviors of hydrogen isotopes (D2/H2) for various cation exchanged zeolite beads using BET at 77 K. The study predicts the D2/H2 adsorption selectivity based on the results obtained with BET. These hydrogen isotope adsorption results will provide a foundation for future processes for tritium separation.

Tritium is radioactive isotope, emitting beta ray, released as tritiated water from nuclear power plants. Due to the danger of radioactive isotope, the appropriate separation of tritium is essentially carried out for environment and safety. Further, it is also promising material for energy production and research. The tritiated water can be treated by diverse techniques such as water distillation, cryogenic distillation, Girdler-sulfide process, and catalytic exchange. After treatment, it is more desirable to convert as gas phase for storage, comparing to liquid phase. However, achieving complete separation of hydrogen gases with very similar physical and chemical properties is significantly challenging. Thus, it is necessary to develop materials with effective separation properties in gas separation. In this presentation, we present hydrogen isotope separation in the gas phase using modified mesoporous silica. Mesoporous silica is a form of silica that is characterized by its mesoporous structure possessing pores that range from 2 to 50 nm in diameter. This material can be functionalized to selectively capture and separate molecules having specific size and affinity. Here, the silver and copper incorporated mesoporous silica was synthesized to tailor a chemical affinity quantum sieving effect, thereby providing separation efficiency in D2/H2. The adsorption quantities of H2 and D2 were determined by sorption study, and the textural properties of each mesoporous silica were analyzed using N2 physisorption. The selectivity (D2/H2) in diverse feed composition (1:1, 1:9, and 1:99 of D2/H2) was estimated by applying ideal adsorbed solution theory to predict the loading of the gas mixture on bare, Ag- and Cu-mesoporous silica based on their sorption study. Further, the performance of each mesoporous silica was evaluated in the breakthrough adsorption under 1:1 mixture of D2 and H2 at 77 K.

Carbon 14 (14C) is radioactive isotope of carbon which emits beta ray with long half-life (5730±30 years). Since the 14C is significantly hazardous for human being, the appropriate process to treat 14C is necessary. From the nuclear power plant, the ion exchange resin, graphite, and activated carbon are the main source of 14C. During the effort to reduce the volume of those wastes, the 14C is inevitably occurred as carbon dioxide (CO2) form, so called 14CO2. Thus, the development of technology to permanently capture and safely dispose 14CO2 is required. In this presentation, we introduce the decommissioning technology ranging from 14CO2 capture to solidification. First, the new class of glass adsorbent is developed which can irreversibly capture CO2 even under mild conditions. This material promotes the dissolution of alkaline earth ions due to the unstable glass structure. Then, the physical and chemical optimization of glass adsorbent enhances the performance of CO2 capture. Further, room temperature geopolymeric solidification is also performed to safely dispose 14C without any potential release.