Green hydrogen has emerged as a key clean fuel for the future, promising zero emissions when produced with renewable energy. But the process usually demands large volumes of purified freshwater, which is a costly challenge in water-scarce regions.
On the other hand, over 80% of global wastewater is released untreated into the environment, causing serious ecological harm.
Now, a team led by RMIT University has found a way to solve both problems with one invention.
Their experimental technology turns wastewater’s contaminant load into a catalyst for producing green hydrogen, offering a path toward sustainable fuel production without the need for freshwater.
The research, conducted with the University of Melbourne, Australian Synchrotron, and the University of New South Wales, aims to transform a global environmental liability into a productive asset.
The team’s breakthrough uses metals already present in wastewater, such as platinum, chromium, and nickel, to enhance the hydrogen production process. Instead of filtering out these metals, the system captures and uses them.
“The advantage of our innovation over others to produce green hydrogen is that it harnesses wastewater’s inherent materials rather than requiring purified water or additional steps,” said Associate Professor Nasir Mahmood from RMIT’s School of Science.
The team created special electrodes with an absorbent carbon surface that pulls metals from the wastewater. These metals then form stable catalysts that help conduct electricity and accelerate the water-splitting process.
“The metals interact with other elements in the wastewater to boost the electrochemical reactions needed for splitting water into oxygen and hydrogen,” Mahmood said.
The carbon material used for these electrodes is made from agricultural waste, adding another layer of sustainability and cost efficiency to the system.
Green fuel, cleaner water
In lab tests, the researchers placed two electrodes into a container of partially treated wastewater and applied renewable energy.
At the cathode, water molecules gained electrons and released hydrogen gas. At the anode, they lost electrons and produced oxygen.
“The produced oxygen can be reintegrated into wastewater treatment plants to enhance their efficiency by reducing organic content,” said Mahmood.
The system ran continuously for 18 days with minimal decline in performance.
The wastewater used had been pre-treated to remove solids, organic matter, and nutrients, making it representative of real-world applications.
RMIT’s innovation is part of a broader platform of catalytic systems aimed at using difficult water sources like wastewater and seawater for clean hydrogen production.
“Our innovation addresses both pollution reduction and water scarcity, benefiting the energy and water sectors,” said Professor Nicky Eshtiaghi of RMIT’s School of Engineering. “By using wastewater, the process helps reduce pollution and makes use of materials considered to be waste.”
The team is now seeking industry and government partners to scale up the technology. Co-researcher Dr. Muhammad Haris said more research is needed to test the method across different wastewater types.
“The method needs to be tested with different types of wastewater to ensure it works universally,” said Haris.
The study is published in ACS Electrochemistry.
