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

First-principles calculations offer a useful complement to experimental approaches for characterizing H2, D2 and T2 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 Fe3B and amorphous Fe3B. 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 Fe3B 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 H2, D2 and T2 in each material and consider which material would be best suited for membrane-based isotope separations at high temperatures.