Alkaline composite inorganic membrane for high temperature carbon dioxide separation

Abstract

Abstract The development of carbon dioxide separation and capture technologies is necessary to achieve a carbon-neutral society. Focusing on Direct Air Capture (DAC), a technology for the direct capture of carbon dioxide from the atmosphere. Although Li4SiO4-based membranes have been reported as a separation membrane development using alkali ceramics, the carbon dioxide desorption temperature of Li4SiO4 is high, around 700°C. To use it for CO2 methanation and methanolation reactions, it’s necessary to develop separation membranes for m-DAC using materials that can desorb CO2 at around 300°C. This hasn’t yet been considered. Therefore, the aim of this study was to develop an effective alkaline adsorbent for CO2 recovery that absorbs and desorbs CO2 at around 300°C. Membranes with Na2CO3 supported on an α-Al2O3 substrate showed a permeability of 3.58 x 10−10 [mol m−2 s−1 Pa−1] for N2 and 3.93 x 10−10 [mol m−2 s−1 Pa−1] for CO2 after two coatings, which is selective for CO2. However, the membranes didn’t show CO2 adsorption and the substrate broke after three coatings, suggesting that the α-Al2O3 substrate was alkali-sensitive and that the thermal decomposition of Na2CO3 wasn’t advanced.