Tech watch: Innovation turns wastewater into a hydrogen asset

From the newsletter

An experimental invention developed by researchers from Australia’s RMIT University could transform wastewater into a valuable resource for green hydrogen production. Unlike conventional methods, which require purified water, this innovation leverages the contaminants in wastewater to boost hydrogen generation.

• With an estimated  80% of global wastewater discharged untreated, this innovation offers an opportunity to transform an environmental liability into a valuable resource.

• The technology is particularly relevant for Africa, where reliance on desalination increases production costs, impacting the feasibility of green hydrogen projects.

More details

• According to the lead researcher, Professor Nasir Mahmood, the technology, in the form of electrodes, works by harnessing metals naturally present in partially treated wastewater, including platinum, chromium and nickel, to enhance green hydrogen production. These metals act as catalysts, accelerating the electrochemical reactions required to split water into hydrogen and oxygen without being consumed in the process.

• The electrodes feature an absorbent carbon surface that captures metals from the wastewater, forming stable and highly efficient catalytic sites. This structure helps conduct electricity effectively and speeds up the electrolysis process, allowing hydrogen to be produced more efficiently than traditional methods that rely on purified water.

• The carbon used in the electrodes is derived from agricultural waste, making the technology  not only cost-effective but also aligned with circular economy principles. By using waste products to create the electrodes, the process reduces reliance on virgin materials while simultaneously converting another type of waste, wastewater, into a productive resource.

• Meanwhile, Singapore-based Horizon has developed what is arguably the world’s first 5 MW Anion Exchange Membrane (AEM) electrolyser, which is expected to lower the cost of green hydrogen for industrial applications. The initial technology is being deployed at Rockcheck Steel Group in China where the green hydrogen produced will be used in the steelmaking process to reduce coal consumption and carbon emissions in the sector.

• The electrolyser is designed to address cost and efficiency barriers that have often limited widespread green hydrogen deployment. Compared with traditional alkaline electrolysers, Horizon’s AEM electrolyser is said to reduce power consumption by 10–20%, while also promising a lower levelized cost of hydrogen (LCOH). Its modularity allows for scalability and flexible deployment, and the capital cost is expected to compete with conventional alkaline systems, making it an attractive option for large-scale hydrogen production.

• Complementing these industrial-scale efforts, a team at Ashoka University in India has developed a nickel-based catalyst enhanced with custom-designed ligands to improve the efficiency of the hydrogen evolution reaction (HER). This reaction is central to green hydrogen production via electrolysis, where water molecules are split into hydrogen and oxygen. By combining nickel with specially designed ligands, the team has created a catalyst that is both more efficient and more stable than traditional nickel-based systems.

• This innovation stands out because of its potential to replace expensive platinum catalysts, which are currently the benchmark for hydrogen production but are scarce and costly. The ligand-modified nickel catalyst reduces the energy required for electrolysis, demonstrating a lower overpotential while maintaining durability over extended use. This makes it a promising solution for cost-effective and scalable green hydrogen production, particularly in regions seeking affordable alternatives to precious-metal catalysts.

Our take

• RMIT’s technology demonstrates that innovation and circularity can go hand in hand. 

• The dominance of university-based technologies indicates that institutions of higher learning remain at the forefront of innovation, driving solutions for complex challenges like green hydrogen production.

• With adequate investment in robust research and development it may be possible to discover more cost-efficient methods of producing green hydrogen.