As we've detailed, CO2 can be directly recovered from the atmosphere, or coal plant flue gasses, and then chemically processed into useful hydrocarbons - up to and including gasoline.
But, we've also documented the use of algae, as cultivated in "bio-reactors" and "fed" with Carbon Dioxide, and other nutrients, from coal-fired power plants, to recycle emissions into useful substances.
There are many strains of algae, and they produce a variety of compounds. Herein is documented an effort undertaken by Dow Chemical and an algal science company, Algenol Biofuels, to produce ethanol by recycling Carbon Dioxide.
Some excerpts:
"Dow Chemical and Algenol Biofuels, a start-up company, are set to announce Monday that they will build a demonstration plant that, if successful, would use algae to turn carbon dioxide into ethanol as a vehicle fuel or an ingredient in plastics."
(Note the "synergy" mentioned in the following excerpt.)
"The ethanol would be sold as fuel, the companies said, but Dow’s long-term interest is in using it as an ingredient for plastics, replacing natural gas. The process also produces oxygen, which could be used to burn coal in a power plant cleanly, said Paul Woods, chief executive of Algenol, which is based in Bonita Springs, Fla. The exhaust from such a plant would be mostly carbon dioxide, which could be reused to make more algae...."