WASHINGTON: A sapphire-coloured dye — a common industrial pollutant from textile mills — could be used to build rechargeable batteries for wind farms and solar homes to store electricity, a study has found.
Scientists from University at Buffalo in the US showed 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 that can be used to stockpile electricity generated from solar or wind farms for days when there is no sunshine or electricity.
“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,” said lead researcher Timothy Cook, an assistant professor at University at Buffalo.
“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,” said Cook.
“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,” said Anjula Kosswattaarachchi, a PhD student at University at Buffalo.
The study, published in the journal ChemElectroChem, is 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 said.
“One of the things we’re interested in is whether there might be a way to literally repurpose the wastewater itself,” he said.
“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,” he added.
Researchers showed that methylene blue is good at important tasks associated with energy storage. In experiments, the scientists built two simple batteries that employed the dye — dissolved in salt water — to capture, store and release electrons.
The first battery the researchers made operated with near-perfect efficiency when it was charged and drained 50 times.
The results mean that methylene blue is a viable material for liquid batteries. With this established, the team hopes to take the research one step further by obtaining real wastewater from a textile mill that uses the dye. (AGENCIES)
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