A Princeton research team led by Zhiyong Jason Ren, professor of civil and environmental engineering, has been able to isolate hydrogen from industrial wastewater by harnessing sunlight.

Hydrogen is a critical component in the manufacture of many common products, such as plastics, fuels and fertilizers. It's expensive and energy intensive to produce, however, typically relying on fossil fuels, such as oil, gas or coal. 

Ren and his colleagues ran brewery wastewater through a specially designed chamber packed with bacteria that generate electrical current when consuming organic material. Simultaneously, they used a lamp to simulate sunlight—a process known as photocatalysis.

The technique “allows us to treat wastewater and simultaneously generate fuels,” said Jing Gu, a co-researcher and assistant professor of chemistry and biochemistry at San Diego State University.

It was the first time actual wastewater has been used to produce hydrogen, the researchers said. They plan to introduce the technology to industry in the hope that the process will be a viable—and less expensive—way of producing hydrogen for industrial and other uses.