Method and system for capturing carbon dioxide from the air

Abstract

A method for separating and recovering carbon dioxide from ambient air includes continuously bringing ambient air into contact with a basic aqueous solution; electrodialysis of the solution using bipolar and anion-selective ion exchange membranes as well as recycling the depleted solution; separating COfrom the enriched solution and recycling the solution depleted of CO. The absorption is performed in an absorber, open basin, or a combination thereof. Separation is achieved by thermal desorption of COby steam stripping to obtain a carbon dioxide/steam mixture; and/or by chemical reaction of the (hydrogen-) carbonate ions, in which the COcontained is converted into a water-insoluble salt or a gas and simultaneously removed from the solution. The pH of either obtained solution is measured before the recycling or before the separation, and is adjusted to a predetermined value. pH is measured and adjusted based on how absorption and separation are performed.