A process is described for sequestering carbon dioxide. In the process, a carbonate, oxide or hydroxide of a divalent cation is reacted with the carbon dioxide and water and/or with a species resulting from the dissolution of the carbon dioxide in water, to form a hydrogen carbonate of the divalent cation. The carbonate, oxide or hydroxide of the divalent cation has a low solubility in water. The divalent cation of the hydrogen carbonate of the divalent cation thus formed is exchanged for a monovalent cation using an ion exchange medium, to produce a solution of a hydrogen carbonate of the monovalent cation.