J. Shu et al., GAS PERMEATION AND ISOBUTANE DEHYDROGENATION OVER VERY THIN PD CERAMIC MEMBRANES/, Canadian journal of chemical engineering, 75(4), 1997, pp. 712-720
An attempt was made in this study to prepare very thin palladium membr
anes. Pd was electrolessly deposited an the inner side surface of a me
soporous ceramic tube using a persitaltic pump to circulate the electr
oless solution through the tube. To obtain defect-free Pd membranes, a
two-step deposition procedure from a dilute Pd2+ bath and a concentra
ted Pd2+ bath was practised with great care to avoid the difficulties
associated with the mismatch of thermal expansion coefficients between
Pd and the ceramic substrate. The various membranes produced were cha
racterized through a study of their permeation behaviors. A dense Pd m
embrane about 2 mu m thick was permselective to hydrogen, It was found
that in this very thin Pd membrane case, the hydrogen permeation flux
was better correlated to hydrogen pressure using a power higher than
0.5, showing deviation from Sieverts' law. To evaluate the efficiency
of the prepared thin Pd/ceramic membranes, iso-butane dehydrogenation
was used as a model reaction, Enhanced dehydrogenation yields were obt
ained in the membrane reactor due to the separation of hydrogen from t
he reaction medium.