Innovative method for CO2 fixation and storage
Kenji Sorimachi
Abstract
Abstract The concentration of CO 2 in Earth’s atmosphere has been gradually increasing since the Industrial Revolution, primarily as a result of the use of fossil fuels as energy sources. Although coal and oil have been vital to the development of modern civilization, it is now recognized that atmospheric CO 2 levels must be reduced to avoid the serious effects of climate change, including natural disasters. Consequently, there is currently significant interest in developing suitable methods for the fixation of CO 2 in the air and in exhaust gases. The present work demonstrates a simple yet innovative approach to the chemical fixation of extremely low and very high CO 2 concentrations in air, such as might result from industrial sources. This process is based on the use of aqueous solutions of the water-soluble compounds NaOH and CaCl 2 , which react with CO 2 to produce the harmless solids CaCO 3 (limestone) and NaCl (salt) via intermediates such as NaHCO 3 and Na 2 CO 3 . The NaCl generated in this process can be converted back to NaOH via electrolysis, during which H 2 (which can be used as a clean energy source) and Cl 2 are produced simultaneously. Additionally, sea water contains both NaCl and CaCl 2 and so could provide a ready supply of these two compounds. This system provides a safe, inexpensive approach to simultaneous CO 2 fixation and storage.