"The world's commitment to ending plastic pollution is clear and undeniable," said Inger Andersen, Executive Director of the UN Environment Programme (UNEP), when the fifth negotiation session for an international legally binding instrument on plastic pollution, including in the marine environment, came to a close in Busan, Republic of Korea, in December 2024.
As representatives from more than 170 nations and observers from hundreds of organizations roll up their sleeves for the next session in Geneva, Switzerland, scientists and technologists are making headway in research to tackle the global crisis of plastic pollution. Recycling and upcycling efforts are intensifying as the most viable options for managing plastic wastes, with radiation technologies emerging as an innovative, clean and efficient tool to convert used plastic together with biomass into new products.
The scourge of plastic pollution is nothing new. Natural polymers such as rubber and cellulose were widely used before synthetic plastics emerged with the Belgian chemist Leo Baekeland's invention of the first wholly synthetic plastic, Bakelite, in 1907.
By the mid-20th century, global plastic production per year reached about 2 million tonnes. Today, with annual production surpassing 400 million tonnes, it is nearly impossible to go a day without coming across some form of plastic. If business continues as usual, global production of primary plastic is forecast to almost triple, reaching 1100 million tonnes by 2050.
Challenges in Conventional Recycling
Despite recycling efforts, less than 10 per cent of the world's 7 billion tonnes of plastic waste generated globally to date has been recycled. Plastic is not biodegradable. Instead of decomposing, it fragments into smaller pieces resulting in microplastics. These can be found literally everywhere, from the air we breathe to the oceans in Antarctica.
School chairs produced cheaply in the Philippines using conventional recycling techniques. Upcycling, higher-value recycling of plastics, could be achieved by using irradiation, which can enable the use of novel materials in various applications. (Photo: M. Gaspar/IAEA)
Mechanical and chemical recycling are the two major recycling techniques that are currently in place. Mechanical recycling is the most common method, salvaging similar plastics to produce raw materials that can be reintegrated into plastic production. The process involves collecting, sorting, washing and grinding the plastic to be melted and re-processed into new materials.
While relatively cheap, this type of recycling requires the sorting of different polymers, making it difficult to process multi-layered or mixed plastics. Additionally, the process cannot be used more than twice as the quality of recycled materials degrades with each cycle and it only applies to thermoplastics (those that can be re-melted and reshaped into products).
Chemical recycling on the other hand can process a wider variety of mixed plastic wastes, including contaminated and low quality wastes, by breaking them down to their molecular components, transforming them into substances that can be used for producing new plastics or other products, such as fuel. This method is rather costly, as it requires high energy inputs, and developing large scale chemical recycling facilities requires significant investments in infrastructure.
How Can Irradiation Help?
Radiation technology using gamma and electron beams offers unique advantages to reduce plastic waste by offering a cleaner production and recycling process, avoiding the use of potentially harmful additives, and improving energy efficiency.
"The main benefit of irradiation in plastic recycling stems from its ability to alter the chemical structure of plastics at a molecular level," said Azillah Binti Othman, a Radiation Processing Officer at the IAEA. "Irradiation can help reduce plastic waste volumes in two ways: by increasing the re-purposing of hard-to-recycle plastics into valuable products and by developing bio-based plastics to reduce reliance on petroleum-based plastics."
Irradiation is a very effective tool in sorting recycled plastic, which already been washed and ground, according to the type of polymers. This improves the purity of the recycled plastic, and thus its value.
Irradiation can also complement and enhance traditional recycling methods. When combined with a chemical recycling method known as pyrolysis, resulting in radiolysis, plastic waste polymers can be broken down and converted into fuel or chemical components to create new products without adding virgin (non-recycled) polymers.
Workers waiting for plastic pellets in cardboard boxes on a conveyor belt to be transported into the irradiation chamber in an electron beam facility in the Philippines. (Photo: PNRI)
Beyond traditional recycling, irradiation also paves the way for innovative approaches, allowing plastic wastes to be blended with other materials to create more durable products. This facilitates the manufacturing of high performance material that find applications in the automotive or construction industries. For instance, construction materials made from recycled plastic, such as tiles, bricks, lumber and boards, are irradiated in the Philippines to improve their tensile and sheer strength, abrasion resistance and other mechanical properties.
In addition, radiation-assisted technology is also showing promise in making more durable final products when using biomass, a renewable resource. This allows the creation of bio-based plastic and other high value compounds, such as novel packaging materials that would replace conventional petroleum-based plastics.
Irradiated plastic waste was used as a compatibilizer for this thatch in Indonesia, made out of recycled plastic and rice husk. (Photo: Vero)
NUTEC Plastics: from recycling to monitoring microplastics
The IAEA is harnessing the power of radiation technologies, through its NUTEC Plastics initiative, to assist countries in dealing with plastic pollution on two fronts: at the point of source, by introducing new technologies to improve plastic recycling; and in the ocean, where the bulk of plastic waste ends up.
"The focus on the first front is on reducing plastic waste volumes through innovative upcycling, increasing the re-purposing of hard-to-recycle plastics into valuable products and developing bio-based plastics," said Celina Horak, Head of the IAEA Radiochemistry and Radiation Technology Section. "With the help of the NUTEC Plastics initiative, nine countries across Asia, Latin America and Africa are in the process of establishing radiation-assisted pilot plants."
The role of irradiation in helping beat plastic pollution will be discussed during the IAEA's upcoming Third International Conference on Applications of Radiation Science and Technology. Gathering hundreds of experts from radiation-related physics, chemistry, materials science, biology and engineering fields in Vienna, Austria, from 7 to 11 April 2025, #ICARST2025 will be accessible to anyone interested via livestreaming.
International events will also be held in October 2025 in the Republic of Korea, featuring IAEA tools for circular economy assessment and for technological maturity level, and in November 2025 in the Philippines, the first international high level forum on NUTEC Plastics. Both events will include the other aspect of the NUTEC Plastics initiative, the marine monitoring component, where nuclear science is used to identify, trace and monitor plastics in the ocean, particularly microplastics.
