Provided herein are methods of removing carbon dioxide from an aqueous stream or gaseous stream by: contacting the gaseous stream comprising carbon dioxide, when present, with an aqueous solution comprising ions capable of forming an insoluble carbonate salt; contacting the aqueous solution comprising carbon dioxide with an electroactive mesh that induces its alkalinization thereby forcing the precipitation of a carbonate solid from the solution and thereby the removal of dissolved inorganic carbon by electrolysis; and removing the precipitated carbonate solids from the solution, or the surface of the mesh where they may deposit. Also provided herein are flow-through electrolytic reactors comprising an intake device in fluid connection with a rotating cylinder comprising an electroactive mesh, and a scraping device and/or liquid-spray based device for separating a solid from the mesh surface.

An object of the present invention is to provide a carbon dioxide treatment apparatus, a carbon dioxide treatment method, and a method of producing carbon compounds, which have high energy efficiency from carbon dioxide capture to reduction and a high carbon dioxide loss reduction effect. In a carbon dioxide treatment apparatus 100 including: a capturing device 1 that captures carbon dioxide; and an electrochemical reaction device 2 that electrochemically reduces carbon dioxide, an absorption unit 12 of the capturing device 1 brings an electrolytic solution A composed of a strong alkaline aqueous solution and carbon dioxide gas into contact with each other to dissolve carbon dioxide in the electrolytic solution A and absorb the carbon dioxide, supplies an electrolytic solution B that has absorbed carbon dioxide between the cathode and the anode of the electrochemical reaction device 2, and electrochemically reduces the dissolved carbon dioxide in the electrolytic solution at the cathode.

The present disclosure provides systems and methods useful in capture of one more moieties (e.g., carbon dioxide) from a gas stream (i.e., direct air capture). In various embodiments, the systems and methods can utilize at least a scrubbing unit, a regeneration unit, and an electrolysis unit whereby an alkali solution can be used to strip the moiety (e.g., carbon dioxide) from the gas stream, the removed moiety can be regenerated and optionally purified for capture or other use, and a formed salt can be subjected to electrolysis to recycle the alkali solution back to the scrubber for re-use with simultaneous production of one or more further chemicals.

A method of scrubbing a gas, such as flue gas or exhaust gas, comprising carbon dioxide to deplete the gas of carbon dioxide (CO.sub.2), the method comprising the steps of: —scrubbing the gas in a scrubber (210) with a first alkaline, aqueous scrubbing liquid to dissolve carbon dioxide (CO.sub.2) as hydrogen carbonate (HCO.sub.3.sub.−) and/or as carbonate (CO.sub.32-) in the first alkaline, aqueous scrubbing liquid, thereby providing a first spent aqueous scrubbing liquid comprising hydrogen carbonate (HCO.sub.3—) and/or carbonate (CO.sub.32-), the first spent aqueous scrubbing liquid having a pH from about 7 to about 9; —feeding the first spent aqueous scrubbing liquid to an anode chamber of an electrolytic cell (310) comprising the anode chamber (313) and a cathode chamber (312) separated by a membrane (311); —regenerating the first spent aqueous scrubbing liquid in the electrolytic cell (310) by electrolysis, the electrolysis increasing the pH of the first spent aqueous scrubbing liquid in the cathode chamber (312), the electrolysis further depleting the first spent aqueous scrubbing liquid of hydrogen carbonate (HCO.sub.3—) and of carbonate (CO.sub.32-) in the anode chamber (313) by decreasing the pH, the regeneration further comprising generating gaseous hydrogen in the cathode chamber (312) and a gaseous mixture of oxygen and carbon dioxide (CO.sub.2) in the anode chamber (313) by electrolysis; and—withdrawing regenerated alkaline, aqueous scrubbing liquid from the cathode chamber (312) and re-circulating it to the scrubber (210); wherein: —the gaseous hydrogen is withdrawn from the cathode chamber (312); and—the gaseous mixture of oxygen and carbon dioxide is withdrawn from the anode chamber (313).

A process for capturing carbon dioxide (CO.sub.2) emissions and converting the CO.sub.2 into an alcohol fuel is disclosed herein. The process includes capturing CO.sub.2 emissions from an exhaust mechanism of a machine at a CO.sub.2 capture device. The process also includes converting the CO.sub.2 emissions into an alcohol fuel using an electrolyzer.

Provided herein are methods of removing carbon dioxide from an aqueous stream or gaseous stream by: contacting the gaseous stream comprising carbon dioxide, when present, with an aqueous solution comprising ions capable of forming an insoluble carbonate salt; contacting the aqueous solution comprising carbon dioxide with an electroactive mesh that induces its alkalinization thereby forcing the precipitation of a carbonate solid from the solution and thereby the removal of dissolved inorganic carbon by electrolysis; and removing the precipitated carbonate solids from the solution, or the surface of the mesh where they may deposit. Also provided herein are flow-through electrolytic reactors comprising an intake device in fluid connection with a rotating cylinder comprising an electroactive mesh, and a scraping device and/or liquid-spray based device for separating a solid from the mesh surface.

The present invention provides a new method for fixing carbon dioxide. A method for fixing carbon dioxide, includes: a contact step of bringing a mixed liquid containing at least one of sodium hydroxide or potassium hydroxide and further containing at least one of a chloride of a Group 2 element or a chloride of a divalent metal element into contact with a gas containing carbon dioxide; and an electrolysis step of electrolyzing the mixed liquid after the contact to prepare a mixed liquid after the electrolysis. In the contact step, the mixed liquid after the electrolysis is reused as the mixed liquid.

A system and method is disclosed for recovering reagents that are used in removing contaminants from a flue gas stream. The system and method includes contacting the flue gas stream with reagents such as ammonia and sulfuric acid to create an ammonium sulfate stream. The ammoniated sulfate stream is forwarded to an electrodialysis unit wherein the reagents are regenerated and recirculated back to the system.

An acid component removal device for removing an acid component from an acid gas absorbent containing an amine, comprising: an anode; a cathode; and an electrodialysis structure having four compartments formed by arranging an first membrane which is either an anion exchange membrane or a cation exchange membrane, a second membrane which is a bipolar membrane, and a third membrane which is either an anion exchange membrane or a cation exchange membrane and which is the other of the first membrane, in this order, from the anode end to the cathode end between the anode and the cathode, with a space each between the membranes.

Processes and apparatus for electrocatalytically converting carbon dioxide emissions and/or ambient carbon dioxide into useful chemicals are described. The process may include: removing carbon dioxide from ambient air through a carbon capture technique, supplying a carbonate or bicarbonate aqueous solution as cathode feed to a cathode of an electrolytic cell comprising a membrane electrode assembly which includes a bipolar membrane separating an anode from the cathode, and applying an electrical potential difference between the cathode and the anode of the membrane electrode assembly to electrocatalytically reduce the carbonate or bicarbonate aqueous solution to carbon monoxide or another useful chemical.