The Starset SocietyBy: Rhodilee Jean Dolor
The increasing amount of plastic waste polluting the environment is now a pressing global problem. Every year, between 19 million and 23 million tonnes of plastic contaminate aquatic ecosystems, raising concerns over the impact on the environment and human health.
The Plastic Waste Crisis
According to a 2021 study, more than 1,500 species in marine and terrestrial environments ingest plastics, causing suffocation and death. Whales, dolphins, sea lions and sea turtles are particularly susceptible to entanglement with plastic, which raises fatality risks to these animals.
Plastic pollution also compromises human health. Microplastics have already been found in human organs and tissues, including the brain, liver, kidney and placentas. A 2024 study involving patients who underwent surgery to remove plaque from their arteries found that those who had microplastics in their plaque had a higher risk of heart attack, stroke and death.
The carcinogenic chemicals in plastic products that leach into tap water can also potentially cause developmental, reproductive, neurological and immune disorders.
Unfortunately, current efforts to address plastic pollution are not enough. Demand for plastic continues because the material is cheap and convenient to use.
Calls to reuse and recycle neither make significant impact because only around 9% of plastic waste is recycled. About 70% end up in landfills or in nature.
United Nations Environment Programme (UNEP) executive director Inger Andersen herself acknowledged that addressing the plastic waste problem requires better solutions.
“We will not recycle our way out of the plastic pollution crisis: we need a systemic transformation to achieve the transition to a circular economy,” Andersen said.
A breakthrough technology that uses sunlight to turn plastic waste into clean energy offers hope in solving the plastic waste crisis. Interestingly, it can also help address the demand for more sustainable power sources.
Transforming Trash Into Clean Fuel
In a new study published in Chem Catalysis on May 21, researchers used sunlight to turn plastic waste into clean fuel using a method called solar-driven photoreforming.
The process relies on light-sensitive materials called photocatalysts that use sunlight to break down plastics at relatively low temperatures.
The researchers led by Xiao Lu, a PhD candidate at the Adelaide University School of Chemical Engineering, found that the solar-powered system can convert plastic waste into hydrogen and other useful industrial chemicals.
“This is an exciting and rapidly evolving field,” Lu said. “With continued innovation, we believe solar-powered plastic-to-fuel technologies could play a key role in building a sustainable, low-carbon future.”
Clean and Sustainable Source of Power
The researchers were able to extract hydrogen from plastic. Hydrogen is a clean fuel with a range of applications such as for generating electricity for businesses and homes and powering cars.
Hydrogen fuel comes from sustainable sources such as natural gas, nuclear power, biomass, solar and wind. It does not emit planet-warming greenhouse gas at the point of use and produces only water as a byproduct making it a more environment-friendly alternative to fossil fuels.
The common processes of generating hydrogen are by natural gas reforming and electrolysis. The former uses high temperature steam to produce hydrogen from natural gas and currently accounts for about 95% of the hydrogen produced in the US. The latter involves separating water into oxygen and hydrogen.
The researchers said that their approach is more energy efficient than the traditional water splitting process for hydrogen production. They said that plastics, which are rich in hydrogen and carbon, are easier to oxidize so the reaction requires less energy. This also raises potential for large-scale use.
“Plastics are promising feedstocks for photoreforming because they contain rich carbon and hydrogen elements in their polymeric structures. Unlike photocatalytic water splitting, solar plastic reforming is more thermodynamically feasible and can proceed via diverse pathways because organic oxidation reactions circumvent the high energy barrier associated with water oxidation,” the researchers wrote in their study.
Study author Xiaoguang Duan, professor at the Adelaide University School of Chemical Engineering, said that recent experiments have delivered strong results. The process they used produced high hydrogen yields as well as acetic acid and diesel-range hydrocarbons.
Hurdles
Despite the progress, the researchers said that the technology still faces several challenges that need to be addressed before it can be widely adopted.
Duan said that one of the major hurdles involves the complexity of plastic waste itself.
“Different types of plastics behave differently during conversion, and additives such as dyes and stabilisers can interfere with the process. Efficient sorting and pre-treatment are therefore essential to maximize performance and product quality,” Duan said.
The photocatalysts used in the process also need to be durable. These materials should be capable of working under demanding chemical conditions without losing effectiveness. Unfortunately, the current version can degrade over time, affecting their long-term reliability.
“There is still a gap between laboratory success and real-world application,” Duan said. “We need more robust catalysts and better system designs to ensure the technology is both efficient and economically viable at scale.”
The researchers said that separating the final products likewise poses challenges because the reactions produce a mix of gases and liquids that need to be separated. This requires energy-intensive processes that reduce the benefits of the system.
“These obstacles diminish overall energy and economic benefits, highlighting the need for more selective, integrated processes to simplify downstream purification with minimal energy input and system complexity,” the researchers wrote.
Hitting Two Birds With One Stone
Despite the challenges, the researchers have already outlined the steps for scaling up the technology with the goals of boosting energy efficiency and enabling continuous industrial operation over the coming decades.
They said that the photoreforming process can address both the problem with plastic waste and the need for another source of clean energy.
“Plastic is often seen as a major environmental problem, but it also represents a significant opportunity,” said Lu. “If we can efficiently convert waste plastics into clean fuels using sunlight, we can address pollution and energy challenges at the same time.”
