BY THE OPTIMIST DAILY EDITORIAL TEAM
In the race to tackle climate change, cement has long been a stubborn problem. Responsible for about eight percent of global carbon dioxide emissions, it’s the fourth-largest source of CO2 pollution worldwide. But a team of researchers believes a new, unexpected ally could flip the script—seawater.
Scientists at Northwestern University, working with the innovation branch of cement manufacturer Cemex in Switzerland, have unveiled a promising method to create sustainable, potentially carbon-negative cement using seawater electrolysis. Their findings, published in Advanced Sustainable Systems, offer a glimpse at how one of the world’s dirtiest industries might become part of the climate solution.
The sea holds more than salt
At the heart of this new approach is a process called seawater electrolysis. By passing an electric current through seawater, researchers can split its molecules into hydrogen, chlorine, and oxygen gases. But there’s another byproduct: minerals like calcium carbonate, the main ingredient in cement.
In the past, these minerals were viewed as a nuisance. “Researchers who use seawater electrolysis for hydrogen gas production have found those precipitated minerals to be an annoyance,” said environmental engineer Alessandro Rotta Loria, who co-led the study. However, for sustainable cement development, those minerals might be just what the industry needs.
Fine-tuning a sustainable recipe
There’s a catch: the naturally slow pace of mineral formation through electrolysis doesn’t yet match the construction industry’s demand. To address this, the team experimented with how to accelerate and control mineral production in a lab setting.
Using electrodes immersed in seawater, they manipulated several variables: voltage, pH levels, and even the rate at which they injected carbon dioxide into the water. These adjustments affected the volume, density, and crystal structure of the resulting minerals. Some were flaky, some denser, which is ideal for different construction uses like concrete, plaster, and even paint.
“Our experiments suggest that it’s possible to tune the process to produce useful materials tailored to various industry needs,” the researchers noted.
The carbon-negative potential
The real game-changer? If powered by renewable electricity, this technique doesn’t just reduce emissions—it could actively pull carbon dioxide from the atmosphere. As the minerals form, they incorporate CO2, effectively locking it away for hundreds or even thousands of years.
That makes the materials not just carbon-neutral but potentially carbon-negative, a rare and vital goal in climate mitigation efforts.
“It’s about turning an existing problem into a solution,” said Rotta Loria. “Instead of mining limestone from mountains or seabeds—practices that damage ecosystems and release carbon—we can generate needed materials using resources already available in the ocean, while helping to clean the air.”
From lab to construction site
Of course, scaling up remains a challenge. The team acknowledges that the process isn’t yet ready for industrial production. But the insights gained from controlling and improving the mineral yields in the lab are crucial first steps.
If successful, this could eventually reduce the construction industry’s reliance on carbon-intensive methods while opening the door to more environmentally conscious alternatives in everything from skyscrapers to sidewalks.
A sustainable structure, built from sea and science
This emerging approach underscores how rethinking waste and reimagining resources can lead to more circular, resilient solutions. As climate pressures mount, innovations like seawater-based cement production provide a hopeful blueprint for industries to transform themselves from polluters to protectors.
Source study: Advanced Sustainable Systems— Electrodeposition of carbon-trapping minerals in seawater for variable electrochemical potentials and carbon dioxide injections
