Mixed‐matrix membranes based on Li1.6Mn1.6O4 (LMO) ultrathin nanosheet for high‐performance CO2 separation

Abstract

AbstractTwo‐dimensional flake Li1.6Mn1.6O4 (LMO) was added to the Pebax®MH 1657 (Pebax) matrix to prepare mixed‐matrix membranes (MMMs) for CO2/CH4 mixed gas separation. The average pore diameter of the LMO nanosheet was about 10.79 nm: a fast CO2 transport channel could be established in the membrane. In addition, the Li and oxygen defect site (Oδ−) in the LMO had an affinity for CO2, which improved the permeability of the membrane and the selectivity for CO2 separation. Furthermore, the ultrathin structure of LMO with large aspect ratio was also conducive to gas separation. When the LMO filling amount was 2.0 wt%, the permeation rate of pure CO2 gas of Pebax/LMO‐2.0 membrane was 117.9 Barrer, and the CO2/CH4 ideal selectivity was 18.74, which were 119.7 and 35.8% higher than Pebax membrane, respectively. The CO2/CH4 mixed gas separation results of Pebax/LMO‐2.0 membrane showed that the CO2 permeability and CO2/CH4 selectivity were 158.54 Barrer and 33.41, respectively, and were increased by 83.24 and 23.15%, compared with Pebax membrane.