Palladium composite membrane with high reversibility of CO2 poisoning

A palladium membrane was prepared using the electroless plating technique (ELP) for the separation and purification of hydrogen from a gas mixture. Depending on operating conditions, hydrogen flux from the membrane was in the range of 0.012-0.023 mol.m-2.s-1. The membrane performance in the presence of CO2 was investigated. The results of the GC analysis showed that at a feed concentration of 10% CO2 and a difference pressure of 1-2 bar, no traces of CO2 was observed in the permeate side. However, hydrogen permeation through the membrane decreased due to the occupation of the catalytic active sites by CO2.. At the concentration of 20% CO2 and a difference pressure of 1-2 bar, a peak of methane was detected in the permeate side by the GC analysis, this is related to the diffusion of carbon from the feed side to the permeation side. Study on the topography of the membrane surface showed short height hills and wide valleys on its surface. This topology of the surface conduced high chemical resistance of the membrane, so that the effect of CO2 poisoning was reversible without defect creation on the membrane. Recovery of the poisoned membrane was done by exposing it to hydrogen atmosphere at 500 °C for an hour. The obtained results show that the recovery of hydrogen permeation was up to 99%.

Keywords:

Palladium membrane , Electroless plating technique , Poisoning , Membrane recovery