Researchers have found a simple, low-cost way to turn plastic waste into a material that captures carbon dioxide (CO₂) from the air. They see huge potential in using it to transform the plastic that clogs the world’s oceans into part of the solution to the climate crisis – tackling two global crises at once.
Humanity faces two overriding challenges.
First, rising CO₂ emissions are driving climate change, sea-level rise and flooding.
Second, we are polluting the planet – especially the oceans – with mountains of plastic that harm wildlife and, ultimately, ourselves.
Solving either problem is daunting; solving both at once sounds impossible. Nevertheless, researchers have now demonstrated a way to do just that.
Their method converts plastic waste into a solid material that captures CO₂.
This may sound like science fiction, but the technology is already real – and researchers are now working to commercialise it so that plastic waste can shift from being part of the problem to becoming part of the solution.
“With all the plastic waste in the world, we are throwing away a valuable resource because, so little is recycled,” says Margarita Poderyte from the Department of Chemistry of the University of Copenhagen, Denmark. “We have shown how plastic can instead be converted into a material that captures CO₂ from the atmosphere and from industrial flue gas.”
The study – led by Jiwoong Lee’s group at the University of Copenhagen in collaboration with the mission-driven Novo Nordisk Foundation CO₂ Research Center (CORC), Aarhus University, Denmark where Lee is a principal investigator – was recently published in Science Advances.
From plastic bottle to CO2 catcher
The research focuses on polyethylene terephthalate (PET) – one of the world’s most common plastics, used to make soda bottles, food containers, textiles and much more.
Together with colleagues, Margarita Poderyte developed a method to convert PET into a new material called N1,N4-bis(2-aminoethyl) terephthalamide (BAETA).
The transformation is achieved with ethylenediamine – a chemical with strong ability to bind CO₂.
Ethylenediamine is usually used in liquid form at large CO₂ capture plants, where it requires heavy energy input and is difficult to recycle. The researchers instead froze its carbon-binding ability into a solid material that is far more stable and easier to work with.
Ethylenediamine itself is not easy to handle – it evaporates at room temperature and is toxic on contact – but it is inexpensive to produce.
When PET reacts with ethylenediamine at mild temperatures, it forms BAETA – a material that immediately begins absorbing CO₂ from the air.
“BAETA is a solid, stable material that captures CO₂ – and has many promising characteristics compared to existing technologies,” explains Margarita Poderyte. “It is a very versatile material — it can capture CO2 both directly from the air and from industrial flue gas. It operates effectively across a wide range of humidity levels (0–100%) and temperatures (25–170 oC), and it is inexpensive to produce."
Additionally, BAETA can release (desorb) CO2 at the same temperature at which it captures it (when operating at higher temperatures), potentially lowering the overall energy cost of regeneration.
"It can be reused with far less energy and works both at room temperature and in the hot air from factory flue-gas stacks.”
A climate tool that does not run out of power
BAETA captures CO₂ continuously until the material is fully saturated with the gas.
It is remarkably effective at binding CO₂ chemically.
Once saturated, the captured CO₂ can be released by heating the material.
This allows BAETA to be reused again and again, continually pulling CO₂ out of the atmosphere.
The captured CO₂ can then be stored underground or reused as a raw material for new products such as fuels and industrial chemicals. In short, it can either be stored or turned into something useful.
Removing CO₂ from factory flue gas
So far, the researchers have shown that PET can be converted into CO₂-capturing BAETA in the laboratory.
The next step is to scale up the process so that it becomes industrially viable.
BAETA currently takes the form of a powder, but researchers also demonstrated that it can be compressed into pellets that can be assembled into larger systems designed to capture CO₂ directly from industrial flue-gas stacks.
In practice, this means that the flue gas from factories can be cleansed of CO₂ before it reaches the atmosphere.
“BAETA remains effective for a very long time, and the material is both flexible and robust at temperatures ranging from room temperature to about 150 °C,” notes Margarita Poderyte. “This makes it ideal for industrial use, where the air is often hot. In our laboratory tests, we have already shown that it can be reused many times without losing its ability to capture CO₂ over 150 consecutive cycles. The next step is to determine whether it performs just as well when scaled up from small experiments to large-scale systems.”
From climate problem to climate business
According to Margarita Poderyte, another advantage of converting PET into BAETA is that the method places few demands on the quality of the plastic used in the process. The plastic can be low-grade, coloured or degraded – without it making much difference.
For this reason, the approach is particularly well suited for transforming textile waste, contaminated food packaging, or some of the plastic already polluting the world’s oceans into part of the global climate solution.
The researchers therefore hope that their method can help to bridge the gap between efforts to combat climate change and those to tackle plastic pollution.
And if someone can make money from it, that could create even stronger incentives for action.
The team is already scaling up the production of BAETA – from kilograms to several tonnes – while engaging in talks with investors who can see the potential. If successful, the technology could become a real alternative to today’s CO₂ capture systems – cheaper and far less energy-intensive.
“We want to turn our invention into a venture that is also economically viable,” says Margarita Poderyte. “The technological challenge is not the biggest hurdle – what is needed now is investment and a team of people with diverse skills to move the possibility of turning plastic waste into a CO₂ solution out of the laboratory and into the real world.”
