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A new solar-powered water purification film has been developed as a low-tech, high-impact tool for delivering safe drinking water in areas without reliable infrastructure. The material, developed by researchers in Sun Yat-Sen University in China, uses a specially engineered polymer photocatalyst (known as Cz-AQ) to eliminate bacteria and contaminants using only natural sunlight.
According to TechXplore, designed as a floating, ultrathin film, the system works by generating long-lived cleaning agents when exposed to sunlight and water. These agents—oxygen-centered organic radicals (OCORs)—are able to destroy harmful bacteria and break down pollutants, while remaining stable and active for at least five days.
Unlike chlorine treatments, which can create harmful byproducts, or UV systems that require significant electricity, this approach is designed to work in low-resource environments. It continues to function even under weak or diffuse sunlight, which are conditions that typically hinder existing solar-based purification methods.
In controlled testing, the film achieved over 99.995% bacterial removal from 10 liters of heavily contaminated water within just 40 minutes. The film showed strong results against common pathogens such as E. coli and Staphylococcus aureus, and retained its performance throughout more than 50 reuse cycles.
The film’s efficiency is attributed to its use of a photocatalyst (Cz-AQ), which enables the generation of OCORs without rapidly degrading the film itself. This stability gives it a significant advantage over earlier photocatalytic systems, which often suffer from short lifespans and reduced performance in real-world conditions.
Portable, reusable, and requiring no external power source, the technology is especially suited for disaster zones, remote communities, and other regions without access to centralized water treatment. Researchers estimate that a single unit could provide safe drinking water for several adults daily.
As waterborne illnesses continue to impact millions globally, particularly in low-income areas, scalable and decentralized solutions like this sunlight-driven purification film could play an important role in addressing a pressing humanitarian need.
The research’s findings were published in the “Nature Water” journal.
