The University of New South Wales (UNSW) Sydney has conducted a new study which could transform one of the world’s most pollution-heavy chemical industries – turning waste products into fertiliser while cleaning up waterways and cutting emissions.
In the Nature Communications study, two issues are brought together. Using renewable electricity to trigger an electrochemical reaction, the researchers could directly couple CO2 with nitrogen pollutants to form urea.
Industrial activities release large amounts of CO2 into the atmosphere each year, with around 40 billion tonnes released in 2024 alone. At the same time, nitrogen pollutants such as nitrate and nitrite from agriculture and industry contaminate waterways and ecosystems.
Corresponding author Associate Professor and Scientia Fellow Dr Rahman Daiyan says the work is part of a broader push to go beyond the global move to green ammonia, focusing instead on decarbonising the entire fertiliser chain.
“Urea is the fertiliser used to feed the crops for more than half of the world’s population,” Daiyan says.
“But currently, it’s made from natural gas or coal. It’s very fossil-fuel intensive, high-temperature, high-pressure technology with huge emissions.”
The UNSW Sydney-developed catalyst – made of copper and cobalt – shows a strong synergy between the two metals and improved urea production when compared with existing systems.
Dr Daiyan says it’s a “promising foundation” for a circular process that, in future, could convert captured carbon dioxide and nitrogen pollutants into urea.
“The vision is zero-carbon urea where we directly couple waste carbon dioxide with nitrogen pollutants using renewable electricity, rather than relying on ammonia as an intermediate,” he says.
“That allows us to run the system on solar and wind, avoid high temperatures and pressures and reduce emissions.”
Although Australia is a major agricultural exporter, the nation does not produce enough urea domestically and so is a net importer of the fertiliser – relying heavily on overseas supply to meet demand. In 2024, urea imports reached around 3.8 billion tonnes.
If Australia could produce its own clean, locally made urea from waste carbon and renewable electricity, it would strengthen supply chains while lowering emissions.
Write to Aaliyah Rogan at Mining.com.au
Images: Adobe Stock
