CO2 selective separation of Pebax-based mixed matrix membranes (MMMs) accelerated by silica nanoparticle organic hybrid materials (NOHMs)

Abstract

Liquid-like nanoparticle organic hybrid materials (NOHMs) hold great promise in CO2 capture due to tailored nanostructures and functionalities. Herein, we demonstrate a facile and generic method to enhance CO2 selective separation of Pebax-based MMMs by NOHMs. NOHMs with core/corona/canopy structure based on silica with different particle size (120 nm, 220 nm and 380 nm) were prepared, respectively. The basic physicochemical properties of NOHMs and MMMs were examined. Excellent interface compatibility is obtained due to the peculiar property of liquid-like NOHMs in resolving nanoparticles agglomeration. More importantly, CO2-philic moieties (EO segments) in canopy (polyetheramine M2070) endow MMMs with a superior CO2 selective separation. The effect of NOHMs content on mixed gases permeation were systemically investigated. Remarkably, the optimum CO2 permeability reached 246.7 Barrer and a satisfied CO2/N2 selectivity of 66.4 for membrane (P-NOHMs-120-(15)) was obtained, which were increased by 267.1% and 76.1% compared with pristine Pebax membrane, respectively. Moreover, Grand Canonical Monte Carlo (GCMC) molecular simulation was used to investigate how NOHMs improve CO2 selective separation by analyzing interaction parameters (interaction energy, density field distribution and isosteric heat). Finally, the enhanced CO2 selective separation sites were determined. The CO2 selective separation accelerated by NOHMs proposed in present work provides ingenious inspiration for the development of novel fillers in MMMs due to the tailored nanostructures of NOHMs.