Hydrogen is an ideal climate-friendly fuel because it doesn’t release carbon dioxide when it is used. But most hydrogen is produced in ways that result in significant carbon emissions. Thus, the search for green hydrogen goes on.
Last year, engineers at MIT developed a new process for making hydrogen that significantly reduces the carbon footprint of its production. The recipe uses seawater and recycled soda cans.
Pure aluminum reacts with water, breaking up the water molecules to produce aluminum oxide and pure hydrogen. But when aluminum is exposed to oxygen, it forms a shield-like layer that prevents the reaction.
The MIT researchers found that the shield can be removed by treating aluminum with a small amount of gallium-indium alloy. Mixing the pure aluminum with seawater not only produces hydrogen, but the salt in the seawater precipitates out the gallium-indium, making it available for reuse.
The research team carried out a “cradle-to-grave” life cycle assessment of the process, taking into account every step in using the hydrogen-production process at an industrial scale. They found that using recycled aluminum – chopped-up soda cans – is environmentally and economically superior to using “primary” aluminum, mined from the earth. The cans would be shredded into pellet and treated with the gallium-indium alloy. The pellets would be processed near a source of seawater where they would be combined to generate hydrogen on demand.
According to their analysis, the hydrogen produced would be at least competitive economically and environmentally with other potential methods of producing green hydrogen.
**********
Web Links
Study shows making hydrogen with soda cans and seawater is scalable and sustainable
Photo, posted July 29, 2020, courtesy of Bruce Dupree via Flickr.
Earth Wise is a production of WAMC Northeast Public Radio
Leave a Reply