(483g) Hydrogen Isotope Separation By Carbonaceous Materials

Deuterium is useful for developing many of functional materials, such as long-lived LSI, optical fibers with low light attenuation, and deuterium-modified drugs. Moreover, a compact fusion reactor, which uses deuterium and tritium as fuel, has attracted much attention because of the recent technical breakthrough made by Lockheed Martin. Though, separation of hydrogen isotopes are difficult and requires energy intensive processes, quantum molecular sieving, which separates lighter molecules from heavier ones because of the differences in zero-point energies of adsorbed species, is one of the candidates that may be used as the deuterium production process. The promising pore structure for the hydrogen isotope separation is a regular carbon cylindrical pore with a molecular hydrogen size (ca 0.3 nm). However, there are very few adsorbents with such a regular pore structure. We have therefore focused attention on deposition of carbons on the pore surface of zeolites (zeolite-carbon complex: ZCC), deposition of carbons on the surface of activated carbons (molecular sieve carbon: MSC), and mechanical deformation of single wall carbon nanotube (SWNT), to control the size of internal pore and pore entrance. ZCCs and MSCs were synthesized in silico using quench molecular dynamics simulation. The selectivities of D₂ over H₂ of the obtained structures (ZCC, MSC, and deformed SWNT) were evaluated using grand canonical Monte Carlo simulations with the Feynman-Hibbs effective potential (FH-GCMC) and transition state theory, and we have found that those structures are promising for kinetic quantum molecular sieving of hydrogen isotopes.