New Construction Material Captures CO2 Using Seawater and Electricity

Researchers at Northwestern University and CEMEX Innovation Holding have developed a novel construction material using seawater, carbon dioxide, and electricity. This material, detailed in *Advanced Sustainable Systems*, can replace sand and gravel in concrete production and even create cement, plaster, and paint. The process involves running an electric current through seawater, separating water molecules into hydrogen and hydroxide ions. Introducing CO2 then increases bicarbonate ion concentration. These ions react with calcium and magnesium in seawater, forming calcium carbonate (a carbon sink) and magnesium hydroxide (which captures additional CO2). The process mimics coral and shellfish formation, but uses electricity instead of metabolism. The resulting material's properties can be adjusted by altering the electric current or CO2 injection duration, allowing for varying porosity and density. A 50/50 mix of calcium carbonate and magnesium hydroxide can capture one ton of CO2 per two tons of material. The process also produces hydrogen, a potential energy source. While electricity is required, the net emissions depend on the energy source used. This innovation addresses both greenhouse gas emissions and the scarcity of raw materials in cement production.