Carbon dioxide immobilization unit

Abstract

There is provided a carbon dioxide immobilization unit capable of easily immobilizing carbon dioxide in the form of an organic acid or a carbohydrate under a normal environment. An anode and a cathode both having a surface where an oxidoreductase is present are disposed to face each other with a proton conductor in between. Then, when electric power is externally supplied to the carbon dioxide immobilization unit, in the anode, water is decomposed to produce protons, and in the cathode, an organic acid or a carbohydrate is produced from the protons produced in the anode and carbon dioxide. At this time, while a carbon dioxide supply section supplies a high concentration of carbon dioxide to the cathode, oxygen produced in the anode and the organic acid or hydrocarbon produced in the cathode are removed from a reaction system through an oxygen removal section and a product recovery section, respectively.

1 . A carbon dioxide immobilization unit comprising at least:
 a first electrode decomposing water to produce protons;   a second electrode producing an organic acid or a carbohydrate from the protons produced in the first electrode and carbon dioxide; and   a proton conductor transferring the protons produced in the first electrode to the second electrode,   wherein an oxidoreductase is present on a surface of the first electrode or a surface of the second electrode, or both.   
     
     
         2 . The carbon dioxide immobilization unit according to  claim 1 , further comprising a carbon dioxide supply section supplying carbon dioxide to the second electrode. 
     
     
         3 . The carbon dioxide immobilization unit according to  claim 2 , wherein
 the carbon dioxide supply section supplies a gas containing carbon dioxide in concentration of 0.028 to 100 vol % both inclusive.   
     
     
         4 . The carbon dioxide immobilization unit according to  claim 3 , comprising:
 an oxygen removal section removing oxygen produced in the first electrode; and   a product recovery section extracting the organic acid or the carbohydrate produced in the second electrode.   
     
     
         5 . The carbon dioxide immobilization unit according to  claim 1 , wherein
 the first electrode is a dipping type electrode which is directly in contact with a liquid phase or is in contact with the liquid phase with a separator in between, and   the second electrode is a semi-dipping type electrode which is directly in contact with the liquid phase or is in contact with the liquid phase with a separator in between, as well as is in contact with a vapor phase with a gas-liquid separator film in between.   
     
     
         6 . The carbon dioxide immobilization unit according to  claim 1 , wherein
 the first electrode or the second electrode, or both are formed of a conductive porous material.