Co-permeation of deuterium and hydrogen through Pd

Experiments on permeation of deuterium through a palladium membrane, which was accompanied by co-permeation of hydrogen, were performed in the pressure range below 1 Pa. Permeation of deuterium exhibited features of surface limited regime (SLR) both with and without hydrogen co-existence. Release of D2, HD, and H2 molecules from the downstream side of the membrane was observed in presence of hydrogen. No visible blocking of deuterium permeation by hydrogen appeared. The net permeation rate of deuterons in D2 and HD forms in the co-permeation experiments with hydrogen was found to be approximately the same as in the experiments without hydrogen, if the effective deuterium pressure p(D2)+p(HD)/2 remained the same irrespective of the partial pressure of hydrogen p(H2). The experimental data were described by a steady-state permeation model, which took into account D2, HD, and H2 absorption and desorption.