A carbon dioxide treatment apparatus, a carbon dioxide treatment method, and a method for producing a carbon compound that have high energy efficiency in recovery and reduction of carbon dioxide and are highly effective in reducing loss of carbon dioxide. The carbon dioxide treatment apparatus (100) includes a recovery device (1) configured to recover carbon dioxide, an electrochemical reaction device (2) configured to electrochemically reduce carbon dioxide, and a pH adjuster (52), wherein pH of a cathode side electrolytic solution is higher than that of an anode side electrolytic solution, carbon dioxide gas is supplied from a concentration part 11 to a gas flow path on a side of a cathode (21) opposite to an anode (22), and the carbon dioxide gas is reduced at the cathode (21).

A method of operating an electrochemical cell including introducing an aqueous solution into the electrochemical cell, applying a current across an anode and a cathode to produce a product, monitoring the voltage, dissolved hydrogen, or a condition of the aqueous solution, and reversing polarity of the anode and the cathode responsive to one of the measured parameters is disclosed. An electrochemical system including an electrochemical cell including an anode and a cathode, a source of an aqueous solution having an outlet fluidly connectable to the electrochemical cell, a sensor for measuring a parameter, and a controller configured to cause the anode and the cathode to reverse polarity responsive to the parameter measurement is disclosed. Methods of suppressing accumulation of hydrogen gas within the electrochemical cell are also disclosed. Methods of facilitating operation of an electrochemical cell are also disclosed.

A water electrolysis system includes a water electrolytic stack, a water reservoir connected to the water electrolytic stack to supply water to the water electrolytic stack, a water circulation pump supplying the water in the water reservoir to the electrolytic stack; and a control unit configured to, during an operation stoppage of the electrolysis system, control the driving of the water circulation pump to convert the water in the electrolytic stack from an acidic condition to a neutral condition and to regulate a unit cell voltage of the electrolytic stack to a voltage such that an electrolysis reaction does not occur and a chemical state of an anode catalyst is stably maintained.

A system and a method are provided for making hypochlorous acid using saltwater with sodium bicarbonate. The system includes an electrolytic cell, a quantity of saltwater solution, and a quantity of sodium bicarbonate. The quantity of saltwater solution is poured into the electrolytic cell and then undergoes an electrolytic process. As a result of the quantity of saltwater solution going through the electrolytic process, a hypochlorous acid solution is yielded. In order to ensure a pure hypochlorous acid solution is formed, the quantity of sodium bicarbonate can be added into the electrolytic cell along with the quantity of saltwater solution before the electrolytic process or the quantity of sodium bicarbonate can be added into the hypochlorous acid solution after the hypochlorous acid solution is yielded. This process adjusts the pH level of the hypochlorous acid solution, and thus, produces a purer hypochlorous acid solution.

A system and methods for electrolysis of saline solutions are provided. An exemplary system provides a tandem electrolysis cell. The tandem electrolysis cell includes a common enclosure that has two chambers. A first chamber is separated from a second chamber by a cation selective membrane. A common anode and a first cathode (cathode A) are disposed in the first chamber. The first cathode and the common anode are configured to electrolyze a saline solution to hydrogen and oxygen. A second cathode (cathode B) is disposed in the second chamber. The second cathode and the common anode are configured to electrolyze a brine solution in the first chamber to form chlorine and water in the second chamber to form hydrogen and hydroxide ions.

A HOCl manufacturing system is disclosed for production of high potency, safe, consistently pure, stable, authentic HOCl in a deployable, portable, high volume, localized manufacturing unit. The electrolysis method uses a deployable, remote-controlled manufacturing system. The method includes: controlling water flow rate into an electrolysis chamber by providing feedback controlled water pressure; applying feedback controlled current to the electrolysis chamber via an adjustable and high-current power supply; adding sodium chloride brine, via a feedback controlled actuator, to an anode chamber inlet and creating an aqueous mixture; adding sodium hydroxide, via a feedback controlled actuator, to the aqueous mixture; and producing aqueous hypochlorous acid free from hypochlorites, phosphates, oxides, and stabilizers.

Real-time data from cells is recorded during operation of an electrolyzer. Synthetic data is generated based on historical data of the electrolyzer and the cells, the synthetic data comprising synthetic cell voltages and synthetic product output flow, synthetic anolyte pH, feed brine pH, or oxygen in chlorine gas concentration of the electrolyzer. Cell-specific k-factors or U.sub.0 are determined from the historical data. A slow contamination is detected when a difference between the synthetic product output flow, synthetic anolyte pH, feed brine pH, or oxygen in chlorine gas concentration and a real-time product output flow, anolyte pH, feed brine pH, or oxygen in chlorine gas concentration exceeds a first threshold. A fast contamination is detected when cell-specific k-factors or U.sub.0 exceed a second threshold and a trend of a difference between the synthetic cell voltages and real-time cell voltages or a derivative of the difference meets or exceeds a conditional logic rule.

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.

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.

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.