Zirconia-supported hybrid organosilica microporous membranes for CO2 separation and pervaporation

Abstract

Hybrid organosilica membranes have great potential for realizing high-flux, high-selectivity gas separation and pervaporation. Current membranes, however, have one major problem: the intermediate layers between the selective layer and the porous support are made of unstable γ-alumina. In this article, a strongly improved membrane set-up based on mesoporous stabilized zirconia (8YSZ) intermediate layers is reported. This novel membrane showed selectivities in the range of 20–30 for different CO2/N2 mixtures and accompanying CO2 permeances of 1.5–4 m3/(m2.h.bar). In pervaporation tests with water/isopropanol and water/butanol mixtures (5 wt% water), the membrane selectively separated water (separation factor ~150 – 600) and an excellent flux of ~5 kg m-2h−1 was achieved at 70 °C. These results represent an important step towards the industrial application of hybrid silica membranes in applications such as pervaporation as well as the selective removal of CO2. The analysis also shows for the first time that effective gas separation and pervaporation is realized when γ-alumina is substituted for another, more stable membrane material.