Saline Water-Based Mineralization Pathway for Gigatonne-Scale CO2 Management

This perspective proposes a potential pathway to diminish atmospheric CO₂ accumulations which is distinct from traditional carbon capture and geological sequestration strategies and from existing negative emissions technologies (NETs). Unlike conventional sorbent- or solvent-based CO₂ capture processes where substantial energy expenditures are associated with demixing and desorbing CO₂, the single-step carbon sequestration and storage (sCS²) approach relies on electrolytic carbonate mineral precipitation using renewable energy within a simple and scalable process design. Although numerous approaches have implied electrolysis for carbon management, the sCS² approach is unique in the following ways: (1) CO₂ mineralization for promoting solid carbonate formation:

The thermodynamic and kinetic barriers to carbonate precipitation are overcome by direct and in situ electrochemical forcing to stabilize dissolved inorganic carbon and divalent cations [Ca,Mg] to form carbonate minerals. (2) Flow-through membraneless electrolysis: A flowing electrolyte (seawater) is dissociated while in motion. The process utilizes cost-effective mesh electrodes while also decreasing the number of components and assembly steps and reducing the risk of device failure. (3) Integrated electrolytic reactor–rotary drum filter: An electroactive thin-film mesh cathode (eTFC) is suggested to be integrated within a rotary drum filter configuration, allowing for the filtration of dilute and polydispersed mineral precipitates at a low energy cost. These attributes render sCS² as an approach worthy of more detailed evaluation, development, and scaling for global-scale carbon management.