Coral Mineralization Inspired CaCO3 Deposition via CO2 Sequestration from the Atmosphere

We report coral-inspired calcium carbonate deposition via sequestration of CO2 directly from the atmosphere. We observed that a CaCl2 solution containing basic components and carbonic anhydrase induced aragonitic spherulites and acicular morphologies of CaCO3 at the air/solution interface, through the reaction of calcium ions with CO2 dissolved directly from the atmosphere; the resulting crystalline aragonite architectures were very similar to those in scleractinian corals. The addition of an anionic polymer enhanced deposition of CaCO3 at the air/solution interface, which was accompanied by morphological changes including coated spherulites; tabular, cone-shaped, and nanofibrillar calcites; and amorphous calcium carbonate, These architectures are abundant in corals in nature, and the results thus suggest that CaCO3 deposition via CO2 sequestration from the atmosphere, using a solution containing a basic component, carbonic anhydrase, and an anionic polymer, emulates coral mineralization. This study of abiotic mineralization can be used as a tool for understanding coral mineralization in nature, and also has implications for CO2 capture from the atmosphere.