By Abbas Nazil
Scientists at Northwestern University McCormick School of Engineering have developed a new carbon-negative building material created from seawater, electricity, and carbon dioxide, offering a potential breakthrough in sustainable construction and climate mitigation.
The research, led by Alessandro Rotta Loria, focuses on capturing and storing carbon dioxide within solid materials that can be used as alternatives to conventional construction aggregates such as sand and gravel.
The process involves inserting electrodes into seawater and applying a low electric current, which splits water molecules into hydroxide ions while releasing hydrogen gas that can be used as a clean energy source.
Carbon dioxide is then introduced into the seawater, triggering chemical reactions that increase bicarbonate ion concentration and lead to the formation of solid minerals.
These reactions produce calcium carbonate, commonly found in limestone and shells, and magnesium hydroxide, both of which can trap and store carbon dioxide within their structure.
Researchers found that when the material contains a balanced mix of calcium carbonate and magnesium-rich compounds, it can store more than half its own weight in carbon dioxide, making it highly effective for long-term carbon sequestration.
Additional treatment processes can further enhance the material’s ability to absorb and retain carbon, increasing its potential for use in construction applications.
The team also demonstrated that adjusting the electrical current or carbon dioxide input can modify the material’s chemical composition, size, shape, and porosity, allowing it to be tailored for different uses.
Beyond concrete production, the material could be applied in manufacturing cement, plaster, and paint, expanding its relevance across the construction and industrial sectors.
Importantly, the innovation could reduce reliance on mined sand from rivers, coasts, and seabeds, addressing environmental concerns linked to resource extraction and habitat degradation.
The development builds on previous research into carbon storage in concrete and electrification of seawater, marking a significant step toward integrating carbon capture into everyday building materials.
By combining carbon removal with material production, the technology offers a dual benefit of reducing atmospheric carbon dioxide while supporting sustainable infrastructure development.
Researchers believe the approach could play a key role in advancing low-carbon construction practices and contributing to global efforts to combat climate change.
