Absorption of hydrogen isotopes by Pd-Pt alloys

In the search for more profitable working materials for the recently develo ped gas chromatographic hydrogen isotope separation operated around room te mperature without any replacement gas, thermodynamic properties of Pd-Pt al loys for hydrogen absorption and hydride formation were studied in the comp osition range 0-10 at.% Pt, the temperature range 273-493 K, and with a H/M from 2x10(-4) to 0.65. The heat of absorption at infinite dilution and hyd ride formation were determined for H-2 and D-2. The results showed that bot h the heat of absorption and hydride formation decreased with increasing Pt content in the alloy and the isotope effect defined by the ratio of equili brium pressures did not change much with alloy composition. It is implied t hat any alloy used in the present study could be selected as a working mate rial depending on the required operation conditions without significant cha nge in the separation efficiency. (C) 1999 Elsevier Science S.A. All rights reserved.