Abstract: A method for sequestering carbon dioxide (CO2) includes receiving an alkaline fluid stream and receiving an acidic stream. The alkaline fluid stream and the acidic stream are produced by a direct air carbon capture process and the carbonate includes air-captured CO2. The method also includes producing a pH balanced CO2 stream by mixing the alkaline fluid stream with an acidic mixing portion comprising 0% up to 100% of the acidic stream, and storing the pH balanced CO2 stream in a storage location. The storage location can include at least one of a subsurface location, on land, or in a water body. The storage location and the pH balanced CO2 stream are configured to provide long-term storage of the air-captured CO2.

Abstract: A method for capturing and sequestering carbon dioxide (CO2) includes receiving and performing an electrochemical process on the input liquid including water and a salt to produce at least one hydroxide-rich stream, and then capturing CO2 from air using the hydroxide-rich stream and a passive air capture system, thereby producing a liquid carbonate solution containing air-captured CO2. Optional steps include disposing of the liquid carbonate solution, precipitating air-captured CO2 from the liquid carbonate solution as solid carbonate and/or a slurry of carbonate, and mixing the liquid carbonate solution with a hydrogen-rich stream produced by the electrochemical process to generate gaseous CO2. Various integrations and synergies among CO2 capture, renewable energy, water desalination, and metal and mineral extraction are provided.