Efficient N2/CH4 separation by mixed matrix membrane with bimetallic metal–organic framework

Obtaining pure clean energy methane (CH 4 , 3.80 Å) from natural gas is a great challenge task at present due to the similar kinetic diameter with nitrogen (N 2 , 3.64 Å). Herein, a well-defined rod-like bimetallic MOF (Cu 0.5 Ca 0.5 -SBMOF) with an excellent adsorption performance for CH 4 was successfully prepared and blended as filler with Matrimid® 5218 (PI) for preparing mixed matrix membranes (Cu 0.5 Ca 0.5 -SBMOF@PI MMMs). In the separation experiment of N 2 /CH 4 binary gas mixture, both filler loadings and trans -membrane pressure have significant effects on the separation performance of MMMs. When the filler loading is 20 wt%, Cu 0.5 Ca 0.5 -SBMOF@PI MMMs exhibits an excellent separation performance with a separation factor of CH 4 /N 2 up to 17.03, and the permeability of 22.57 barrer for N 2 , which significantly preceded the most reported MMMs. Moreover, the prepared MMMs also show excellent stability. This work has taken an important step towards practical application in the field of separating N 2 /CH 4 gas mixture using MMMs method.