CO2/N2 separation using a ceramic membrane contactor and ZIF-8 in [TEPA][MIm]

Abstract

Capturing CO₂ from the flue gas in the power plant is an important measure to realize the low-carbon combustion of the fossil energy. This paper presents a novel technique which combines traditional methods of the chemical absorption, the physical adsorption and the membrane absorption. The ionic liquid ([TEPA][MIm]) is utilized to improve the CO₂ absorption performance and reduce the energy consumption. While the porous skeleton (ZIF-8) is added to the ionic liquid to reduce the viscosity while introducing the physical adsorption. Moreover, the hydrophobic ceramic membrane is utilized as the separation interface between the gas phase and the liquid phase, which can avoid the entrainment and overflow of the liquid phase while increasing the specific surface area. In terms of the material preparation and the characterization, the addition of ZIF-8 does not destroy the original chemical composition of [TEPA][MIm]. The average contact angle of the hydrophobic ceramic membrane is 140.55°, and the failure temperature is greater than 400 K, which conforms to the application situation of the power plant. In terms of the CO₂ capture and the desorption performance, the maximum CO₂ capture amount reaches 2.03 mol/mol. The temperature of complete desorption is 70 °C. Furthermore, the capture performance after five cycles can reach 80 % of the initial performance. The performance is better than that of the CO₂ capture technology utilizing the traditional monoethanolamine solution.