A lithium–aluminosilicate zeolite membrane for separation of CO2 from simulated blast furnace gas

In this study, for the first time, the small pore size (0.28 × 0.37 nm) Li–aluminosilicate zeolite membrane was synthesized for separation of CO2 from H2–CO2 and H2–CO2–N2–CO (simulated blast furnace gas) gas mixtures. Li–aluminosilicate membranes were prepared on porous clay alumina tubes by sonication mediated hydrothermal method using pre synthesized zeolite powders as seeds. The zeolite formation was confirmed by X-ray diffraction pattern and FESEM analysis. The scanning electron micrograph of the membrane, suggested the uniformity of the dense structure of the membrane. Single-gas and mixed-gas permeation experiments through membranes were carried out at 25 °C using H2, CO2 and N2 single-component gases and mixture of H2–CO2, H2–CO2–N2–CO for simulated blast furnace gas composition. Synthesized Li–aluminosilicate zeolite shows appreciable CO2 adsorption capacity at liquid nitrogen temperature compared with other reported zeolites. In case of single gas permeation, membrane shows usual pattern of permeation. For mixture gas, separation efficiency of Li–zeolite membrane increased abruptly compared to the other zeolite membranes. The maximum CO2–H2, CO2–N2 and CO2–CO separation selectivities were found to be 78, 8.7 and 67.3 respectively, with permeance of H2, CO2 and N2 2.21 × 10−7, 1.01 × 10−7 and 0.8 × 10−7 mol m−2 s−1 Pa−1 at 25 °C respectively.