Advances in Bio-based Polymer Membranes for CO2 Separation

Abstract

The carbon dioxide (CO2) is the chief greenhouse gas accountable for global warming problems across the world. Various technologies are available for CO2 separation like absorption, adsorption, cryogenic distillation, etc., but membrane technology is preferred due to energy efficiency, cost-effective, corrosion-free, and compact modular design. The polymer membranes that are utilized to separate CO2 can either be derived from bio-based polymer or petroleum-based polymer. Bio-based polymers have advantages over petroleum-based as it uses renewable feedstock, less toxic, less carbon emission. The bio-based polymers used to synthesize CO2 selective membrane are chitosan (CS), cellulose, poly (lactic acid) (PLA), etc. Among them, CS is the thermally stable advance biopolymer and possesses good film forming ability. The CO2 separation that occurs in polymer membranes is based on either solution-diffusion or facilitated transport mechanism. Various attempts have been made to improve the CO2 permeance through CS membranes by incorporation of carriers, blending with other polymers or synthesizing mixed matrix membrane (MMM). The polymer membrane used to separate flue gas should be temperature, pressure, and moisture stable, and its performance should not deteriorate with time. Apart from these parameters, various other factors like sorption of gas molecules, gas flow rate, structural changes of the polymers, pH, the active layer thickness, etc. are also important. This chapter gives an overview of CO2 capture technologies, factor affecting the CO2 permeance along with CO2 separation using biopolymer via solution diffusion and facilitated transport mechanism.