(88a) Predictions of H Isotope Separation Using Crystalline and Amorphous 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 as well as amorphous 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 and ternary metal alloys, crystalline Fe3B and amorphous Fe3B. This approach predicts the correct isotopic properties of interstitial H in pure Pd, and we have validated it in the past for the membrane properties for a variety of alloy membranes. We used Sieverts' law to calculate solubility of each component in the Pd-based metal membranes and GCMC for the components in Fe3B membranes. A Kinetic Monte Carlo (KMC) scheme was implemented to find diffusion of H, D, and T at a temperature range of 400 ≤ T ≤ 1200 K. From these results we are able to predict the permeability of H2, D2 and T2 in each of the membranes and predict which material would be best suited for isotope separation.