In a breakthrough that could transform water purification, researchers at Ohio State University have developed “nanofibrous blankets” — lightweight mats that float on water and use ordinary sunlight to break down pollutants. These innovative materials could eliminate the need for energy-intensive ultraviolet (UV) lamps and expensive particle recovery systems, offering a simpler, more sustainable way to clean contaminated water.
Photocatalytic water treatment typically relies on titanium dioxide (TiO₂) nanoparticles, which require UV light to activate. While effective, this method creates two major challenges: UV light makes up less than 5% of natural sunlight, and the nanoparticles must be retrieved after use — a costly and time-consuming process.
To overcome these limitations, the Ohio State team infused TiO₂ nanofibers with copper and wove them into mat-like structures. These copper-enhanced mats absorb visible light, enabling them to function under regular sunlight instead of UV rays. They float on the surface of water, where they can be easily removed after treatment — no complicated recovery systems required.
Lead researcher Pelagia-Iren Gouma described the mats as a first-of-their-kind solution: flexible structures that harness solar energy to clean water while avoiding the pitfalls of earlier methods.
The addition of copper plays a crucial role in making this technology work. It changes the light-absorbing properties of TiO₂, allowing the material to respond to visible light. Copper also encourages the formation of a rare crystal structure called brookite, which enhances the material’s photocatalytic efficiency by keeping energy particles active longer during the cleaning process.
Using a process called electrospinning, the team created nanofibers about 1,000 times thinner than a human hair. These fibers form porous mats that are both lightweight and sturdy, increasing surface area and exposure to sunlight while maintaining structural integrity in water.
To test their effectiveness, researchers used methylene blue — a common industrial dye — in lab experiments. Under visible light conditions (with UV filtered out), the copper-infused mats degraded over 90% of the dye in just four hours. In contrast, the widely used commercial catalyst P25 Degussa showed minimal effectiveness under the same conditions.
Further tests confirmed that the mats generated an electric signal when exposed to visible light — evidence of active energy conversion during the cleaning process. Imaging showed that the copper was evenly integrated into the fibers, replacing some titanium atoms and creating tiny gaps that improve the mats’ cleaning power.
When sunlight hits the mats, it triggers the formation of reactive particles. Some interact with water to produce hydroxyl radicals — powerful agents that break down pollutants. Others combine with oxygen to generate more cleaning radicals. Together, these reactions convert harmful substances into harmless carbon dioxide and water.
The mats even change color — turning yellow instead of white — a visual sign that the copper was correctly added and that the material is absorbing sunlight effectively.
One of the key advantages of these mats is their practicality. They float on water and retain their shape, eliminating the need for external energy sources or complex recovery systems. Electrospinning, the technique used to create the mats, can be scaled up, making commercial production feasible.
Advanced imaging confirmed the uniform distribution of titanium, oxygen, and copper — critical for consistent performance. The materials are safe and stable, and Gouma emphasizes that they pose no environmental harm.
These floating nanofiber mats could have a major impact in industries that deal with water pollution from dyes and chemicals, such as textiles, paper, or manufacturing. They could be placed directly into contaminated ponds or tanks, working without pumps, filters, or costly equipment.
Because they rely solely on sunlight, the mats are especially well-suited for remote areas or developing regions where infrastructure is limited. They offer a low-cost, eco-friendly way to treat water using abundant natural resources.
With funding in place and scalable production methods already identified, the team is optimistic about bringing this technology to market. The mats represent a significant step toward decentralized, low-energy water treatment that is accessible to more people and more places.
As Gouma puts it, “We have the tools to make them in large quantities and translate them to various industries. The only limitation is that it needs someone to take advantage of these abundant resources.”
By turning ordinary sunlight and nanotechnology into a powerful water-cleaning tool, these floating blankets could help secure cleaner water for communities around the world — no UV lamps, no complex filters, just smart science and sunlight.
By Impact Lab
