Carbon Dioxide Separation with Novel Solvents as Liquid Membranes

Glycerol carbonate is studied as a new physical solvent for carbon dioxide separation from CO 2 /N 2 mixtures. CO 2 -selective behavior of glycerol carbonate is explored in an immobilized liquid membrane (ILM) configuration. Pure glycerol carbonate ILMs retained their CO 2 /N 2 selectivity around 80−130 over a large range of CO 2 partial pressures. Its CO 2 selectivity was not affected by the absence of humidity in feed and sweep streams. When exposed to dry feed gas conditions, the CO 2 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 CO 2 facilitation at low CO 2 partial pressures. However, at high CO 2 feed partial pressures, there was a loss of selectivity with the addition of the carriers. The potential for glycerol carbonate based ILMs in CO 2 separation from different CO 2 -containing gas mixtures is discussed and compared with existing solvent/membrane configurations.