Redox-Mediated Separation of Carbon Dioxide from Flue Gas

The proton-coupled electron transfer (PCET) reaction of a quinone has been used to create a pH gradient capable of the active pumping of CO2 through a liquid membrane. The quinone redox couples, hydroquinone/benzoquinone and 2,6-dimethylbenzoquinone/2,6-dimethylhydroquinone, have been investigated in the proton transfer mechanisms associated with electron transfer in sodium bicarbonate solutions. These same conditions have then been applied to an active liquid membrane for proton pumping across a membrane electrode assembly under potential bias, acting as an active membrane for CO2 separation. Qualitative results are reported toward the development of an active redox membrane for CO2 separation from flue gas.