Polyurethane/polyethersulfone dual-layer anisotropic membranes for CO2 removal from flue gas

Abstract

This work studies the preparation of dual-layer polyurethane/polyethersulfone membranes using the co-casting technique and the effects of the evaporation time and the temperature of the coagulation water bath on the membrane morphology are evaluated. Uniform layers with excellent adhesion are obtained. Also, the preparation of dual-layer mixed matrix membranes is carried out with two different particles: activated carbon and silica. The effects of particle content on membrane morphology are explored. The adhesion and homogeneous structure of the layers are maintained at low particle content. For non-particle membranes, increasing the pressure from 1 to 8 bar results in a reduction of CO2 permeability and CO2/N2 ideal selectivity from 19.6 to 13.0 Barrer, and from 66 to 60, respectively. Temperature in the range of 25 to 45 ºC enhances CO2 permeability from 19.6 to 28.9 Barrer, although CO2/N2 selectivity decreases from 66 to 43. In the case of mixed matrix membranes, the presence of activated carbon and silica enhances CO2 permeability from 19.6 to 22.6 and 23.1 Barrer, respectively. Moreover, higher feed pressure values lead to an increase of more than 40% in CO2 permeability for the membranes with activated carbon, showing good potential for flue gas treatment.