A Review: CO2 Utilization

Global warming due to the accumulation of atmospheric CO2 has received widespread attention in recent years. Although various CO2 capture technologies have been proposed, using the captured CO2 from power plants is increasingly popular because of concerns with regard to the safety of underground and ocean CO2 storage. Various techniques related to utilization of CO2 from the exhausted gas of power plants are discussed in this article. The existing and under-development technologies for CO2 utilization in the world are briefly reviewed. Two categories, direct utilization of CO2 and conversion of CO2 to chemicals and energy products, are used to classify different forms of CO2 utilization. Regarding the direct utilization of CO2, in addition to its use in soft drinks, welding, foaming, and propellants, as well as the use of supercritical CO2 as a solvent, CO2 capture via photosynthesis to directly fix carbon into microalgae has also attracted the attention of researchers. The conversion of CO2 into chemicals and energy products via this approach is a promising way to not only reduce the CO2 emissions, but also generate more economic value. Since CO2 is just a source of carbon without hydrogen, a clean, sustainable and cheap source of hydrogen should be developed. This article reviews the literature on the production of biofuel from microalgae cultivated using captured CO2, the conversion of CO2 with hydrogen to chemicals and energy products, and sustainable and clean sources of hydrogen, in order to demonstrate the potential of CO2 utilization.