Carbon Dioxide Separation with Novel Solvents as Liquid Membranes

Abstract

Glycerol carbonate is studied as a new physical solvent for carbon dioxide separation from CO2/N2 mixtures. CO2-selective behavior of glycerol carbonate is explored in an immobilized liquid membrane (ILM) configuration. Pure glycerol carbonate ILMs retained their CO2/N2 selectivity around 80−130 over a large range of CO2 partial pressures. Its CO2 selectivity was not affected by the absence of humidity in feed and sweep streams. When exposed to dry feed gas conditions, the CO2 permeability through pure glycerol carbonate ILMs was about 100 barrer, which increased to about 350 barrer in the presence of humidified feed streams. Addition of small amounts of facilitating carriers such as poly(amidoamine) dendrimer (generation zero) and sodium glycinate appears to significantly help CO2 facilitation at low CO2 partial pressures. However, at high CO2 feed partial pressures, there was a loss of selectivity with the addition of the carriers. The potential for glycerol carbonate based ILMs in CO2 separation from different CO2-containing gas mixtures is discussed and compared with existing solvent/membrane configurations.