Turning dirty water into clean hydrogen

Hydrogen production could soon get a lot more sustainable.

New research from Princeton Engineering suggests that reclaimed wastewater can replace clean water in hydrogen production, cutting both costs and environmental impact. The study found that using treated wastewater instead of purified water could reduce water treatment costs by nearly half and energy cost by over 60%.

This represents a major step forward for green hydrogen. Traditionally, electrolysis, the process of splitting water into hydrogen and oxygen using electricity, depends on pure water which takes time, energy and money, and often puts extra pressure on local freshwater supplies.

Professor Z. Jason Ren and his team explored an approach using reclaimed water from wastewater treatment plants in a proton exchange membrane electrolyser, the same technology used in commercial hydrogen production. They discovered that adding a small amount of acid to the process helps counteract minerals like calcium and magnesium that can clog the system.

By adjusting the chemistry, the researchers were able to produce hydrogen continuously for more than 300 hours with no performance loss and without releasing any acid or contaminants into the environment.

“It’s expensive to remove all those ions so you have ultrapure water going into the electrolyser,” said Professor Ren. “Now, you can just acidify it a bit, then put ion-containing water into the electrolyser, and it lasts for more than 300 hours without apparent issues.”

The result is a simpler, cheaper and more sustainable way to make hydrogen that turns a waste stream into a valuable resource.

Read more: Dirty water boosts prospects for clean hydrogen