A method for reducing ion concentration of a solution and converting gas, the method comprising: (a) providing a multi-chamber electrodialysis cell with ion exchange barriers separating chambers of the electrodialysis cell, the electrodialysis cell comprising: (i) a gas chamber; (ii) a product chamber; (iii) a salt concentration chamber positioned between the gas chamber and the product chamber; (iv) an acid chamber; (v) a first anion exchange barrier positioned between the product chamber and the acid chamber; (vi) a second anion exchange barrier positioned between the gas chamber and the salt concentration chamber; (vii) a first cation exchange barrier positioned between the product chamber and the salt concentration chamber; (viii) a cathode in the gas chamber, wherein the cathode comprises a catalyst; and (ix) an anode; (b) flowing a fluid being a gas or a mixture of gases through the gas chamber, wherein said fluid is carbon dioxide gas mixed with oxygen/air, flowing a solution being treated through the product chamber, and flowing a solution through the salt concentration chamber; and (c) applying an electric potential between the anode and the cathode wherein: the carbon dioxide gas is electro-reduced at the cathode in the gas chamber to first aqueous anions, cations in the solution being treated migrate across the first cation exchange barrier to the salt concentration chamber to associate with said first anions from the fluid being a gas or a mixture of gases that migrate through the second anion exchange barrier to form a salt in the salt concentration chamber, thereby reducing the ion concentration of the solution being treated, increasing the salt concentration of the solution flowing through the salt concentration chamber and converting at least a portion of the gas into the salt, and second anions in the solution being treated migrate across the first anion exchange barrier to associate with cations in the acid chamber to form an acid solution in the acid chamber. (a) providing a multi-chamber electrodialysis cell with ion exchange barriers separating chambers of the electrodialysis cell, the electrodialysis cell comprising: (i) a gas chamber; (ii) a product chamber; (iii) a salt concentration chamber positioned between the gas chamber and the product chamber; (iv) an acid chamber; (v) a first anion exchange barrier positioned between the product chamber and the acid chamber; (vi) a second anion exchange barrier positioned between the gas chamber and the salt concentration chamber; (vii) a first cation exchange barrier positioned between the product chamber and the salt concentration chamber; (viii) a cathode in the gas chamber, wherein the cathode comprises a catalyst; and (ix) an anode; (i) a gas chamber; (ii) a product chamber; (iii) a salt concentration chamber positioned between the gas chamber and the product chamber; (iv) an acid chamber; (v) a first anion exchange barrier positioned between the product chamber and the acid chamber; (vi) a second anion exchange barrier positioned between the gas chamber and the salt concentration chamber; (vii) a first cation exchange barrier positioned between the product chamber and the salt concentration chamber; (viii) a cathode in the gas chamber, wherein the cathode comprises a catalyst; and (ix) an anode; (b) flowing a fluid being a gas or a mixture of gases through the gas chamber, wherein said fluid is carbon dioxide gas mixed with oxygen/air, flowing a solution being treated through the product chamber, and flowing a solution through the salt concentration chamber; and (c) applying an electric potential between the anode and the cathode wherein: the carbon dioxide gas is electro-reduced at the cathode in the gas chamber to first aqueous anions, cations in the solution being treated migrate across the first cation exchange barrier to the salt concentration chamber to associate with said first anions from the fluid being a gas or a mixture of gases that migrate through the second anion exchange barrier to form a salt in the salt concentration chamber, thereby reducing the ion concentration of the solution being treated, increasing the salt concentration of the solution flowing through the salt concentration chamber and converting at least a portion of the gas into the salt, and