Predictions of H isotope separation using crystalline and amorphous metal membranes: A computational approach

摘要

First-principles calculations offer a useful complement to experimental approaches for characterizing H_2, D_2 and T_2 permeance through dense metal membranes. In this study we performed calculations that combine ab initio density functional theory calculations and statistical mechanics to describe the properties of interstitial H and its isotopes in crystalline Pd-based binary alloys, crystalline Fe_3B and amorphous Fe_3B. We used Sieverts' law to calculate the solubility of each isotope in the Pd-based metal membranes and Grand Canonical Monte Carlo for the isotopic solubilities in Fe_3B membranes. A kinetic Monte Carlo (KMC) scheme was implemented to examine diffusion of H, D, and T at elevated temperatures. From these results we are able to predict the permeability of H_2, D_2 and T_2 in each material and consider which material would be best suited for membrane-based isotope separations at high temperatures.