Urine-derived urea helps make key chemical used in EV batteries, rocket fuel

Researchers at the University of Adelaide have developed an electrochemical method that can turn urea into hydrazine, a chemical used in industries ranging from pharmaceuticals to rocket propulsion. The study could offer a lower-impact approach to producing hydrazine while creating a use for urea-rich waste. The team from the university’s School of Chemical Engineering used electricity and sodium chloride to drive the conversion. Their approach also worked with several urea sources, including pure urea, urea-rich wastewater and human urine. A cleaner route to hydrazine Hydrazine is an important industrial chemical and is also being explored for energy applications, including fuel cells and systems designed for long-duration space missions. However, conventional manufacturing methods can require hazardous chemicals and significant amounts of energy. “Hydrazine is industrially synthesized from ammonia or a derivative, urea, created through an established method,” lead author Dr Pengtang Wang said. “These methods have been developed and employed for decades, but they rely on other hazardous chemicals and use a great deal of energy, which makes it costly and environmentally challenging. Developing a new and mild alternative to this conventional process would represent an important step towards greener and more economical hydrazine production.” The researchers designed an electrochemical process that uses electricity to initiate the chemical conversion under relatively mild conditions. Salt helps trigger the reaction Urea was selected as the starting material because it is widely available, including in human urine. The researchers say this could create an opportunity to recover a useful chemical from a readily accessible waste stream. “Urea was chosen as the feedstock because it is abundant in human urine,” he revealed. “Turning this readily available resource into hydrazine could provide a potential pathway for fuel production, including applications in fuel cells and long-duration space missions. Sodium chloride helps drive the reaction by generating adsorbed chlorine species on the electrode surface.” “These chlorine species react with urea to form N-chlorourea, which is then converted into hydrazine through a simple hydrolysis process.” The process therefore uses sodium chloride as part of the reaction pathway while electricity supplies the energy needed to drive the conversion. Process works with waste urea. Testing showed that the technique could achieve high-yield hydrazine production. Its performance was also demonstrated using different urea feedstocks, suggesting the method could potentially handle materials beyond purified laboratory-grade urea. Using wastewater and urine as feedstocks could be particularly useful if the process can eventually operate efficiently at larger scales. It could combine waste treatment with chemical production, although further engineering work is needed before such applications become practical. The researchers caution that the current system still faces technical and economic limitations. These include salt accumulation and the energy required to isolate the hydrazine product after the reaction. More work needed before scale-up “Although this electrochemical strategy enables efficient urea-to-hydrazine conversion, practical engineering challenges and associated cost bottlenecks, including salt accumulation and energy consumption required for product isolation, remain to be addressed,” Wang added. He further mentioned that the researchers will focus on lowering costs, simplifying product separation, improving continuous operation, and developing more practical reactor designs. They believe these advances could help establish a sustainable route for hydrazine production powered by renewable electricity. If those challenges can be resolved, the researchers believe renewable electricity could eventually power a different approach to hydrazine manufacturing while helping turn urea-containing waste into a valuable chemical feedstock. The study was published in the journal Nature Synthesis. Get the latest in engineering, tech, space & science - delivered daily to your inbox.A versatile writer, Sujita has worked with Mashable Middle East and News Daily 24. When she isn't writing, you can find her glued to the latest web series and movies.