A functional water concentration sensor includes: a light source which emits ultraviolet light; a container capable of holding functional water having a pH between 6 and 9, inclusive, and containing hypochlorous acid and hypochlorite dissociated from the hypochlorous acid; a light-receiving element; and a signal processor. The signal processor calculates the concentration of the hypochlorite in the functional water on the basis of the output signal, calculates the percentages of the hypochlorous acid and the hypochlorite in the functional water on the basis of the pH of the functional water and the dissociation constant of the hypochlorous acid, and calculates the concentration of the hypochlorous acid in the functional water on the basis of the calculated hypochlorite concentration and the calculated percentages.

Systems and methods for increasing the concentration of a desired product in gas phase output streams of CO.sub.x electrolyzers are described.

It is provided a process for recycling lithium ion batteries comprising shredding the lithium-ion batteries and immersing residues in an organic solvent; feeding the shredded batteries residues in a dryer producing a gaseous organic phase and dried batteries residues; feeding the dried batteries residues to a magnetic separator removing magnetic particles; grinding the non-magnetic batteries residues; mixing the fine particles and an acid producing a metal oxides slurry and leaching said metal oxides slurry; filtering the leachate removing the non-leachable metals; feeding the leachate into a sulfide precipitation tank; neutralizing the leachate; mixing the leachate with an organic extraction solvent; separating cobalt and manganese from the leachate using solvent extraction and electrolysis; crystallizing sodium sulfate from the aqueous phase; adding sodium carbonate to the liquor and heating up the sodium carbonate and the liquor producing a precipitate of lithium carbonate; and drying and recuperating the lithium carbonate.

It is provided a process for recycling lithium ion batteries comprising shredding the lithium-ion batteries and immersing residues in an organic solvent; feeding the shredded batteries residues in a dryer producing a gaseous organic phase and dried batteries residues; feeding the dried batteries residues to a magnetic separator removing magnetic particles; grinding the non-magnetic batteries residues; mixing the fine particles and an acid producing a metal oxides slurry and leaching said metal oxides slurry; filtering the leachate removing the non-leachable metals; feeding the leachate into a sulfide precipitation tank; neutralizing the leachate; mixing the leachate with an organic extraction solvent; separating cobalt and manganese from the leachate using solvent extraction and electrolysis; crystallizing sodium sulfate from the aqueous phase; adding sodium carbonate to the liquor and heating up the sodium carbonate and the liquor producing a precipitate of lithium carbonate; and drying and recuperating the lithium carbonate.

The present invention refers to the field of flue gas purification, which discloses a method and apparatus for capturing carbon dioxide and producing sulfuric acid by sodium bisulfate; using a three-format electrodialysis apparatus to convert the desulfurized by-product NaHSO.sub.4 into H.sub.2SO.sub.4 while capturing CO.sub.2 in the flue gas in the cathode chamber. Under the action of electric field drive and ion exchange membrane, HSO.sub.4.sup.− enters the anode chamber to generate H.sub.2SO.sub.4 and is concentrated, and Na.sup.+ enters the cathode chamber to generate NaOH; the flue gas containing CO.sub.2 to be treated is introduced from the cathode chamber and absorbed by NaOH. The invention provides a simple, green, and economic proceeding method to capture the carbon dioxide in the flue gas during the comprehensive utilization of sodium bisulfate solution, which is of better environmental benefits and improvement of the flue gas treatment technology and reducing the pressure of desulfurization gypsum treatment.

The present invention refers to the field of flue gas purification, which discloses a method and apparatus for capturing carbon dioxide and producing sulfuric acid by sodium bisulfate; using a three-format electrodialysis apparatus to convert the desulfurized by-product NaHSO.sub.4 into H.sub.2SO.sub.4 while capturing CO.sub.2 in the flue gas in the cathode chamber. Under the action of electric field drive and ion exchange membrane, HSO.sub.4.sup.− enters the anode chamber to generate H.sub.2SO.sub.4 and is concentrated, and Na.sup.+ enters the cathode chamber to generate NaOH; the flue gas containing CO.sub.2 to be treated is introduced from the cathode chamber and absorbed by NaOH. The invention provides a simple, green, and economic proceeding method to capture the carbon dioxide in the flue gas during the comprehensive utilization of sodium bisulfate solution, which is of better environmental benefits and improvement of the flue gas treatment technology and reducing the pressure of desulfurization gypsum treatment.

The present invention describes ways of increasing the production efficiency of a saline water electrolysis cell and of consuming CO.sub.2 gas and sequestering it from the atmosphere. This is achieved by the introduction of CO.sub.2 gas into the catholyte of the electrolysis, where reaction of the CO.sub.2 with the hydroxide ions present in the catholyte reduces the pH of the catholyte, thereby increasing production efficiency of the electrolysis cell. The preceding reaction forms bicarbonate and/or carbonate, thus sequestering the reactant CO.sub.2 gas from the atmosphere. The CO.sub.2 gas may be introduced either directly into the cathode area of the electrolysis cell, or into the electrolyte prior to its introduction into the electrolysis cell. Corresponding apparatus is also provided.

Chemical reaction devices involving acid and/or base, and related systems and methods, are generally described.

Chemical reaction devices involving acid and/or base, and related systems and methods, are generally described.

A method for making an aqueous hypochlorous acid (HClO) solution includes electrolyzing a solution of sodium chloride to produce a solution of sodium hypochlorite; and producing the aqueous hypochlorous acid solution by adjusting a pH of the solution of sodium hypochlorite to a value within a range of 3 to 8 by adding a selected weak acid to the solution of sodium hypochlorite to produce a buffer including the selected weak acid and a salt of the selected weak acid.