From Blue Dye, Green Energy

A colorant called methylene blue is a common ingredient in the wastewater generated by textile mills. But chemistry researchers at the University at Buffalo think it may be possible to give this industrial pollutant a second life powering batteries.

Their recent study shows that the dye, when dissolved in salt water, is good at storing and releasing energy on cue. That makes it a promising material for use in large, rechargeable liquid-based batteries—the kind that future wind farms and solar homes could use to stockpile electricity for calm or rainy days.

“Methylene blue can be harmful to health, so it’s not something you want to dump into the environment without treating it,” says lead researcher Timothy Cook, assistant professor of chemistry at UB. He says there are ways to remove it from water, but they’re expensive and generate other kinds of waste products.

That problem led researchers to think outside of the box. “What if instead of just cleaning the water up, we could find a new way to use it?” says Anjula Kosswattaarachchi, a PhD student in chemistry who worked on the study. “That’s what really motivated this project.”

In experiments, the scientists built simple batteries that showed that the dye is well-suited to capture, store and release electrons—all crucial jobs in the life of a power cell.

Now the team hopes to keep going by obtaining real wastewater from a textile mill for further testing.

The project is particularly meaningful to Kosswattaarachchi. Before coming to UB, she worked in textiles, developing new fabric technologies for the Sri Lanka Institute of Nanotechnology. Textiles are one of that country’s most important economic sectors, but pollution is a major downside.

“We believe that this work could set the stage for an alternative route for wastewater management, paving a path to a green-energy storage technology,” she says.