HYDROGEN PURIFICATION USING A MICROPOROUS HYDROTALCITE-SILICA COMPOSITE MEMBRANE

Chemical

Abstract

A novel thin microporous composite membrane of a dual-element hydrotalcite-silica was prepared on porous alumina support by sol-gel method. Strong CO2 adsorption on hydrotalcite material inhibited the diffusion of H2 through the membrane and decreased H2 permeances significantly so that CO2 preferentially permeated. The effects of pressure difference across the membrane, operating temperature and CO2 feed concentration on the CO2 separation performance of the membrane were investigated using synthetically mixed gas. The CO2 permeance and CO2/H2 separation selectivity decreased with increasing the temperature due to the loss of the membrane ability for CO2 adsorption with temperature. Further increase of the pressure difference across the membrane decreased both CO2 permeance and CO2/H2 separation selectivity. The CO2 feed concentration with 40% showed the best performance with a CO2/H2 separation selectivity of 10.59.