Customised ultra-microporous filler for efficient CO2/CH4 separation in mixed matrix membranes

Abstract

Herein, ion-exchanged porous carbon (IE-HC) with uniform and interconnected ultra-microporous was prepared using the in situ ion activation method. Then, the IE-HC was doped into Pebax to prepare mixed matrix membranes (MMMs). Notably, the IE-HC is uniformly dispersed in the membrane matrix and the polymer chains form a ‘knot-like’ structure, resulting in considerably enhanced mechanical properties of the MMMs. The interconnected, uniform ultra-microporous structure creates multi-dimensional diffusion channels for gas diffusion. Meanwhile, the filler IE-HC builds tortuous paths within the membrane, and the functional groups on its surface improve the selectivity for CO2 gas. When the loading amount of the IE-HC is 7 wt%, the separation performance of the membrane reaches its optimal level. The CO2 permeability and selectivity of MMMs are 211.2% and 158.0%, respectively, higher than those of pure Pebax.