The invention is directed to a process to prepare elemental sulphur by (i) contacting an aqueous solution comprising bisulphide with oxidised sulphide-oxidising bacteria under anaerobic conditions wherein elemental sulphur is produced and a reduced sulphide-oxidising bacteria is obtained and (ii) wherein the reduced sulphide-oxidising bacteria are oxidised by transfer of electrons to an anode of an electrochemical cell to obtain the oxidised sulphide-oxidising bacteria.

The present invention relates to methods for selective binding, selective membrane transport and storage of carbon dioxide (CO.sub.2) in aqueous media. The method of the present invention comprises providing an aqueous acceptor solution containing at least one acceptor compound having a free guanidino and/or amidino group, which is contacted with a gas containing carbon dioxide to bind the carbon dioxide in the acceptor solution. The acceptor solutions containing bound carbon dioxide obtained thereby are useful for storing carbon dioxide in aqueous media, for again releasing the carbon dioxide, and for use in electrochemical processes, such as electrodialysis, to selectively transport bound carbon dioxide through separation membranes into aqueous media. The present invention further relates to the preparation of carbonates starting from acceptor solutions containing bound carbon dioxide.

The present invention relates to an air purifier (1) comprising a body (2) having an air inlet (I) through which the air in the environment is sucked and a clean air outlet (O) through which the cleaned air is released to the environment, a first CO.sub.2 sensor (10) which is disposed at the air inlet (I) and a second CO.sub.2 sensor (11) which is disposed at the clean air outlet (O), a CO.sub.2 adsorption unit (3) which chemically adsorbs the carbon dioxide in the air by supplying a basic solution, a pump (4) which delivers the ambient air to the CO.sub.2 adsorption unit (3) through the air inlet (I), abase tank (8) which supplies the basic solution to the CO.sub.2 adsorption unit (3), an acid tank (7) wherein the air of which the carbon dioxide is adsorbed is treated with an acidic solution, and an electrodialysis unit (5) which separates the salt components formed after the ambient air is treated with the basic solution and the acidic solution into acid and base.

Integrated systems comprising both i) heat and mass exchange systems and ii) electrolysis stacks are disclosed, together with related methods of use. The disclosed systems cool and/or dehumidify air using two streams of salt solutions as liquid desiccants.

A method and system for electrochemically regenerating hydroxide (MOH) and carbon dioxide (CO.sub.2) from an alkali metal carbonate (M.sub.2CO.sub.3) via an electrochemical reactor that can replace a conventional thermochemical causticizing operation in a DAC system. The electrochemical reactor comprises: a cathode having an inlet for receiving an electrolyte feed stream comprising MOH, M.sub.2CO.sub.3 and H.sub.2O, and an outlet for discharging an electrolyte product stream comprising MOH, M.sub.2CO.sub.3, H.sub.2O and H.sub.2; a porous hydrophilic transport barrier in adjacent contact with the cathode; a porous hydrophilic anode in adjacent contact with the transport barrier configured and operable to generate CO.sub.2 in the presence of MOH while suppressing their recombination; a porous hydrophobic CO.sub.2 and O.sub.2 separation barrier in adjacent contact with the anode; and a product gas exit channel in adjacent contact with the CO.sub.2 and O.sub.2 separation barrier and for discharging an anode product stream comprising at least CO.sub.2.

The invention relates to a method for purifying a carrier gas which comprises oxygenated impurities in a first oxidation degree, the purification method comprising the circulation, advantageously uninterrupted, of the carrier gas through and along a direction XX′ of a filter, the filter being made of an oxygen scavenger material which has a redox potential E°, and of which a first portion is in a reduced redox state and within which the oxygenated impurities are scavenged and/or pass from the first oxidation degree to a second oxidation degree, the method further comprising the application to the filter of a greater electric potential ΔV, as an absolute value, than the redox potential E° during a main purification cycle CP.

A system for producing gas streams for use in synthetic fuel production through CO2 capture and water splitting is disclosed. The system includes a CO2 capture device configured to receive a CO2-containing stream and including an aqueous alkaline solution. The alkaline solution includes hydroxide and/or carbonate ions. The CO2 capture device generates a carbon-rich solution when the alkaline solution absorbs CO2. The carbon-rich solution includes carbonate and/or bicarbonate ions. The system also includes an electrolyzer fluidically coupled to the CO2 capture device, and defining a volume including an anode region having an anode, and a cathode region having a cathode. The volume includes an electrolyte solution having a pH gradient generated by an electric current, causing the electrolyte solution to be acidic in the anode region and alkaline in the cathode region. The carbon-rich solution is received into the electrolyzer. The electrolyzer generates hydrogen, oxygen, and CO2 streams.

A carbon capture system includes: (a) an absorber having an inorganic solvent carbon dioxide capture section, a water wash section between the organic solvent carbon dioxide capture section and the inorganic solvent carbon dioxide capture section, a flue gas inlet at the organic solvent carbon dioxide capture section and a treated flue gas outlet at the inorganic solvent carbon dioxide capture section, (b) a stripper, (c) a polishing circuit, and (d) a water wash circuit. A related method of carbon capture includes sequentially subjecting the flue gas to (i) organic solvent carbon dioxide capture, (ii) water washing and (iii) inorganic solvent carbon dioxide capture.

A process for capturing carbon dioxide (CO.sub.2) emissions and converting the CO.sub.2 into other products is disclosed herein. The process includes capturing CO.sub.2 emissions from an exhaust mechanism at a CO.sub.2 capture device. The process also includes converting the CO.sub.2 emissions into a carbon-based product using catalysis, such as an electrochemical process or a photocatalytic process.

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.