Wastewater dye is good at storing and releasing energy on cue
Research shows that the chemical — a component of wastewater in textile-making — is good at tasks associated with energy storage
A sapphire-colored dye called methylene blue is a common ingredient in wastewater from textile mills.
But University at Buffalo scientists think it may be possible to give this industrial pollutant a second life. In a new study, they show that the dye, when dissolved in water, is good at storing and releasing energy on cue.
This makes the compound a promising candidate material for redox flow batteries — large, rechargeable liquid-based batteries that could enable future wind farms and solar homes to stockpile electricity for calm or rainy days.
The research appeared online on Aug. 13 in the journal ChemElectroChem.
“Methylene blue is a widely used dye. It 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, PhD, assistant professor of chemistry in the UB College of Arts and Sciences. “There’s been a lot of work done on ways to sequester methylene blue out of water, but the problem with a lot of these methods is that they’re expensive and generate other kinds of waste products.”
“But what if instead of just cleaning the water up, we could find a new way to use it? That’s what really motivated this project,” says first author Anjula Kosswattaarachchi, a UB PhD student in chemistry.
The study is just the first step in assessing how — and whether — methylene blue from industrial wastewater can be used in batteries.
“For this to be practical, we would need to avoid the costly process of extracting the dye from the water,” Cook says. “One of the things we’re interested in is whether there might be a way to literally repurpose the wastewater itself.
“In textile-making, there are salts in the wastewater. Usually, to make a redox flow battery work, you have to add salt as a supporting electrolyte, so the salt in wastewater might be a built-in solution. This is all speculative right now: We don’t know if it will work because we haven’t tested it yet.”