Abstract: Systems and methods for capturing carbon dioxide from multiple different sources at least in part via the electrochemical production of acids and/or bases are generally described. The carbon dioxide may be captured at least in part via exposure of a first input gas stream from a first source to a capture agent (e.g., a liquid solution comprising electrogenerated basic species) to generate carbonate anions, and then subsequent conversion of at least some of the carbonate anions to bicarbonate anions via capture of additional carbon dioxide from a second input gas stream from a second, different source. The first source may be ambient air (e.g., for a direct air capture process), while the second source may be a point source of carbon dioxide (e.g., industrial effluent).

Abstract: Systems and methods for obtaining lithium-containing materials from liquid streams are generally described. In some instances, aqueous streams are treated with a lithium selective agent prior to and/or following electrolysis of the stream to produce basic species such as hydroxide ions. In some cases, the lithium selective agent is a solids-forming agent such as a precipitant (e.g., phosphoric acid/phosphate) or a solid sorbent (e.g., aluminum hydroxide). The electrogenerated basic species may induce carbon dioxide capture to form carbonate and/or bicarbonate anions. Coupling of the electrolytic processes and/or carbon dioxide capture processes to the lithium selective separation processes may promote efficient generation of value-added lithium-containing materials such as lithium hydroxide and/or lithium carbonate.

Abstract: Systems and methods for capturing and releasing carbon dioxide at least in part via the electrochemical production of acids and/or bases are generally described. An aqueous input stream that includes a dissolved salt such as sodium chloride may be input into an electrolysis assembly to produce acidic and/or basic species. The basic species may promote capture of carbon dioxide (e.g., via direct air capture or from a point source). The acidic species may promote subsequent release of the carbon dioxide to form a carbon dioxide-rich stream. In some instances, at least some streams are concentrated and/or recycled, thereby improving overall system performance and/or efficiency.

Abstract: Systems and methods for removing metal cation impurities such as alkaline earth metal cations via exposure to captured carbon dioxide are generally described. The captured carbon dioxide, which may be in the form of dissolved carbonate anions, may induce the formation of solid alkaline earth metal (e.g., as a precipitated salt), thereby removing a relatively high percentage of dissolved alkaline earth metals. The carbon dioxide may be captured in a gas-liquid contact vessel and then transferred to a component of the system where metal cation impurity removal is performed. The systems and methods can be useful for treating (or pre-treating) liquid streams such as brines or wastewaters and/or for softening liquid streams.