Nanomaterial transforms waste into a solar solution to decontaminate water and produce hydrogen
Researchers from the Federal University of São Carlos (UFSCar) and the Federal University of Rio Grande do Norte (UFRN) have developed a nanomaterial capable of integrating water treatment and hydrogen production into a single process driven by sunlight. Produced from steel industry waste and seashells, the technology combines hydroxyapatite (HAp) and iron oxide (Fe₂O₃) in a photocatalytic heterojunction. In experiments, the material degraded approximately 75% of the methylene blue present in the water in just two and a half hours while simultaneously demonstrating the capacity to generate H₂, thereby linking the circular economy, environmental remediation, and solar fuel production.
Industrial waste takes on a new role in the hydrogen economy
Among the various compositions evaluated, the one designated HFe40—containing 40% iron oxide—showed the best performance. The Fe₂O₃ was recovered from blast furnace dust, a steelmaking by-product otherwise destined for disposal, while the hydroxyapatite was obtained from seashell waste. In hydrogen generation tests, 20 milligrams of the material, exposed to solar radiation for four hours in a solution containing lactic acid, produced more than 25 micromoles of H₂ per gram of material. The heterojunction also demonstrated stability: after five reuse cycles in methylene blue degradation, its photocatalytic activity dropped by only 6%, and it maintained similar performance when tested in rainwater, lake water, and tap water.
Supported by institutions such as FAPESP, Capes, and CNPq, the study points to a technological pathway in which industrial and biological waste products can be converted into functional materials with higher added value. However, the researchers emphasize that scaling up the application still requires further advances, particularly regarding increased efficiency, hydrogen production measurement, and long-term stability assessment.
