Scientists turn plastic waste into clean fuel using solar energy

Researchers successfully implemented a solar-powered system that converts harmful waste products such as plastic and carbon emissions into clean fuel. (Hailey Hoffman/Cascadia Daily News via AP)

Researchers from Cambridge University have demonstrated that carbon dioxide can be captured from industries or the air and converted into clean fuels using only solar energy.

In their peer-reviewed publication, published on Monday, the researchers detailed the development of a solar-powered reactor that can transform captured CO2 and plastic waste into sustainable fuels and other valuable chemical products.

In their experiments, researchers successfully converted CO2 into syngas – an essential component for producing sustainable liquid fuels. Additionally, they were able to transform plastic bottles into glycolic acid, which is widely used in the cosmetics industry.

In their latest experiment, the researchers took CO2 from industrial exhaust or directly from the air - unlike their previous experiments where CO2 was taken from different sources - and converted it into sustainable fuel.

Researchers say more improvements are required before this technology can be used at an industrial scale, however, it can be highlighted as an important step towards producing clean fuels that can power the economy without relying on environmentally destructive oil and gas extraction.

“We’re not just interested in decarbonisation, but de-fossilisation – we need to completely eliminate fossil fuels in order to create a truly circular economy,” Erwin Reisner, one of the researchers said in a news release accompanying the study. “In the medium term, this technology could help reduce carbon emissions by capturing them from industry and turning them into something useful, but ultimately, we need to cut fossil fuels out of the equation entirely and capture CO2 from the air.”

This innovation has been inspired by photosynthesis – the process by which plants convert sunlight into food – using artificial leaves which have the ability to produce fuel from CO2 and water using just the power of the sun.

The researchers were also inspired by carbon capture and storage (CCS) techniques, which involve capturing CO2 and subsequently injecting and storing it underground, according to the release.

“CCS is a technology that’s popular with the fossil fuel industry as a way to reduce carbon emissions while continuing oil and gas exploration,” explained Reisner. “But if instead of carbon capture and storage, we had carbon capture and utilisation, we could make something useful from CO2 instead of burying it underground, with unknown long-term consequences, and eliminate the use of fossil fuels.”

HOW DOES THE TECH WORK?

In their experiments, researchers made adjustments to their technology, enabling it to work with flue gas or directly from the air. This adaptation allows CO2 and plastics to be converted into fuel and chemicals using only solar power.

Then, through the process of bubbling air into an alkaline solution, the researchers selectively captured CO2 and allowed other gases like nitrogen and oxygen to escape harmlessly.

The system has two compartments—in one compartment, the captured CO2 solution is converted into syngas, a basic fuel. In the other compartment, plastics are transformed into valuable chemicals solely using sunlight.

“The plastic component is an important trick to this system,” co-first author Dr Motiar Rahaman explained. “Capturing and using CO2 from the air makes the chemistry more difficult. But, if we add plastic waste to the system, the plastic donates electrons to the CO2. The plastic breaks down to glycolic acid, which is widely used in the cosmetics industry, and the CO2 is converted into syngas, which is a simple fuel.”

Reporting for this story was paid for through The Afghan Journalists in Residence Project funded by Meta.