Cyclic process using alkaline solutions created from electrolytically decarboxylated water as an atmosphereic co2 collector followed by repeated electrochemical recovery of co2 with simultaneous production of dihydrogen for liquid hydrocarbon synthesis

Abstract

A method for the controlled removal of bicarbonate from alkaline water and its replacement with a strong base that is capable of chemically absorbing CO 2 from the atmosphere as a carbonate and bicarbonate solution. This bicarbonate and carbonate solution is reprocessed in the central compartment of an electrolytic cation exchange module (E-CEM) to take advantage of the removal of CO 2 from the air, and as an energetic byproduct of E-CEM dihydrogen production, and to regenerate the original strong base absorbent solution. Thus, this process is cyclical in nature, and no chemicals are needed except an initial source of alkaline water.

What is claimed as new and desired to be protected by Letters Patent of the United States is: 
     
         1 . A cyclical method for producing a strong alkaline solution for atmospheric CO 2  capture, subsequently followed by recovery of the CO 2  along with regeneration of the alkaline solution to complete the cycle, comprising:
 feeding an alkaline solution containing bicarbonate and carbonate ions into an electrochemical module to form a hydroxide solution;   allowing the hydroxide solution to chemically absorb CO 2  from the atmosphere to form a re-equilibrated bicarbonate and carbonate solution; and   feeding the re-equilibrated bicarbonate and carbonate solution back into the electrochemical module.   
     
     
         2 . The method of  claim 1 , wherein the pH of the hydroxide solution decreases as the CO 2  from the atmosphere is absorbed. 
     
     
         3 . The method of  claim 1 , wherein the hydroxide solution is regenerated in the electrochemical module from the re-equilibrated bicarbonate and carbonate solution fed into the electrochemical module. 
     
     
         4 . The method of  claim 1 , additionally comprising adjusting a surface to volume ratio of the hydroxide solution to maximize the absorption rate of CO 2  from the atmosphere into the hydroxide solution. 
     
     
         5 . The method of  claim 1 , wherein as the pH and hydroxide concentration increase in the hydroxide solution, the rate of CO 2  absorption from the atmosphere into the hydroxide solution increases. 
     
     
         6 . The method of  claim 1 , wherein the hydroxide solution comprises an alkali metal hydroxide. 
     
     
         7 . The method of  claim 1 , wherein the hydroxide solution comprises sodium hydroxide. 
     
     
         8 . A cyclical method for producing a strong alkaline solution for atmospheric CO 2  capture, subsequently followed by recovery of the CO 2  along with simultaneous production of dihydrogen and regeneration of the alkaline solution to complete the cycle, comprising:
 feeding an alkaline solution containing bicarbonate and carbonate ions into a center compartment of an electrolytic cation exchange module (E-CEM), wherein the E-CEM comprises an anode, an anode compartment adjacent to the anode, a first cation membrane between the anode compartment and the center compartment, the center compartment, a cathode compartment, a second cation membrane between the center compartment and the cathode compartment, and a cathode adjacent to the cathode compartment;   feeding water into the anode compartment and cathode compartment;   applying a source of electricity to the anode, wherein O 2  is formed in the anode compartment, CO 2  is formed in the center compartment, and H 2  and hydroxide are formed in the cathode compartment;   removing the CO 2  formed in the center compartment and the H 2  formed in the cathode compartment;   collecting an effluent from the cathode compartment comprising the hydroxide formed in the cathode compartment;   allowing the effluent from the cathode compartment to chemically absorb CO 2  from the atmosphere to form a re-equilibrated bicarbonate and carbonate solution; and   feeding the re-equilibrated solution back into the center compartment of the E-CEM.   
     
     
         9 . The method of  claim 8 , wherein the pH of the effluent from the cathode compartment decreases as the CO 2  from the atmosphere is absorbed. 
     
     
         10 . The method of  claim 8 , wherein an effluent from the anode compartment, an effluent from the center compartment, or both are combined with the effluent from the cathode compartment to form a combined effluent, and wherein the combined effluent chemically absorbs CO 2  from the atmosphere to form a re-equilibrated bicarbonate and carbonate solution. 
     
     
         11 . The method of  claim 10 , wherein the pH of the combined effluent decreases as the CO 2  from the atmosphere is absorbed. 
     
     
         12 . The method of  claim 8 , wherein hydroxide is regenerated in the cathode compartment from the re-equilibrated bicarbonate and carbonate solution fed into the center compartment. 
     
     
         13 . The method of  claim 8 , additionally comprising adjusting a surface to volume ratio of the cathode effluent to maximize the absorption rate of CO 2  from the atmosphere into the effluent from the cathode compartment. 
     
     
         14 . The method of  claim 8 , additionally comprising increasing the applied electricity to increase the pH and hydroxide concentration of the effluent from the cathode compartment. 
     
     
         15 . The method of  claim 8 , wherein as the pH and hydroxide concentration increase in the effluent from the cathode compartment, the rate of CO 2  absorption from the atmosphere into the effluent from the cathode compartment increases. 
     
     
         16 . The method of  claim 8 , wherein the hydroxide formed in the cathode compartment comprises an alkali metal hydroxide. 
     
     
         17 . The method of  claim 8 , wherein the hydroxide formed in the cathode compartment comprises sodium hydroxide.