Industrial hydrazine wastewater comes from a variety of sources and poses significant health and ecological risks. Traditional treatment methods, such as Fenton oxidation and electrocatalysis, often have high energy consumption and/or require additional chemicals. 

Researchers from the Institute of Chemistry of the Chinese Academy of Sciences (CAS) have developed a solar-driven photocatalytic system that efficiently removes hydrazine from wastewater and generates hydrogen simultaneously.

In a study published in Nature Water, a research team led by Prof. LIN Yuze developed narrow-bandgap heterojunction organic photovoltaic catalysts (OPCs) coated with an Al₂O₃ protective layer to create stable photocatalytic nanoparticles, OPC@Al₂O, for efficient and stable solar-driven hydrazine wastewater remediation.

The OPC@Al₂O₃ system has several advantages: broad-spectrum sunlight harvesting, efficient photogenerated charge utilization, stable operation in complex aqueous matrices, and easy catalyst recovery and reuse. Driven by a proton-coupled electron transfer mechanism, the photocatalytic process enables the efficient, sustained degradation of hydrazine under solar irradiation, producing hydrogen as a valuable energy product without generating toxic byproducts.

Exposed to simulated sunlight (AM 1.5 G, 100 mW cm⁻²), the system reduced the hydrazine concentration in wastewater from 640 ppm to a trace level of 0.038 ± 0.01 ppm within five hours. Its wastewater treatment efficiency exceeded that of previously reported solar photolysis systems by more than two orders of magnitude. The treated water met both industrial and agricultural safety standards and demonstrated substantially improved biosafety compared with wastewater treated by conventional Fenton oxidation.

The findings demonstrate a practical, efficient, and scalable strategy for converting hazardous industrial wastewater into valuable products using solar energy. By coupling pollutant removal with hydrogen production, the study highlights a promising pathway toward more sustainable wastewater treatment and resource recovery technologies.

This work was supported by the CAS Project for Young Scientists in Basic Research, the Strategic Priority Research Program of CAS, and the National Natural Science Foundation of China.