Solar energy could help purify water, researchers find

A team of researchers at the University of Illinois Urbana-Champaign have suggested that renewable solar energy could play a crucial role in purifying water.

Currently, water purification processes rely on electrochemical separation processes that are able to separate different particles within a solution. Although energy-efficient, this technique relies on energy derived from nonrenewable sources, such as fossil fuels.

Instead, the research team has made a breakthrough by integrating solar energy into the electrochemical separation process using a semiconductor, demonstrating that water remediation can be powered in part – and perhaps exclusively – by renewable energy sources.

In this method, the chemists used a semiconductor to integrate solar energy into an electrochemical separation process powered by a redox reaction, which manipulates ions’ electric charge to separate them from a solution like water. 

The researchers tested the method and were able to effectively separate and remove dilute arsenate, a byproduct of arsenic from steel and mining industries, from wastewater. The success of the experiment was very promising for the future of the water treatment and environmental protection industries.

“Global electrical energy is still predominantly derived from nonrenewable, fossil-fuel-based sources, which raises questions about the long-term sustainability of electrochemical processes, including separations,” said lead investigator Xiao Su. “Integrating solar power advances the sustainability of electrochemical separations in general, and its applications to water purification benefit the water sector as well.”

In May, the International Energy Agency (IEA) found that investment in renewable energy sources is on course to reach $1.7tn (£1.37tn) this year, with more money being spent on funding solar energy sources than oil and gas for the first time.

The findings of the study were published in the journal Small.