The Influence of Polymer Concentration and Formation Technique on Gas Transport and Gas Sorption Properties of Copolyetherimide-Based Composite Membranes Containing MIL-101 Filler

Abstract

Composite mixed-matrix membranes for gas separation containing copolyetherimide Siltem^® as the polymer matrix and metal-organic framework MIL-101 (10 wt %) as the active filler, were obtained using dry and wet-dry formation techniques. It has been found that the polymer concentration in the initial solution does not significantly affect the CO₂ and CH₄ permeability of the film membranes obtained by dry molding. The addition of MIL-101 increases the CO₂/CH₄ selectivity of the dry-formed membranes approximately by 2 times compared to the selectivity of the filler-free polymer membranes. The materials synthesized by the wet-dry formation possess increased permeability and inverted CO₂/CH₄ selectivity, which indicates a change in the gas transport mechanism. With the increase of polymer concentration, the selectivity of the membranes obtained by the wet-dry technique, increases significantly due to the formation of the dense selective layer.