A team of chemists in Copenhagen has shown how everyday PET plastic — the clear material in millions of drink bottles and food containers — can be chemically rewritten into a material that pulls carbon dioxide from the air and industrial exhausts. The group used a simple aminolysis reaction to turn post-consumer PET into an organic solid they call BAETA, and reported CO₂ capture capacities as high as 3.4 moles per kilogram for the pure material. According to the peer-reviewed paper from the University of Copenhagen, the process works at mild conditions, can be run on mixed consumer waste, and was demonstrated at a 1-kilogram lab scale as a first step toward industrial production.
“The beauty of this method is that we solve a problem without creating a new one,” lead author Margarita Poderyte said, describing how plastic that would otherwise be landfilled or drift into oceans becomes the feedstock for CO₂ capture. That framing — tackling plastic pollution and climate emissions together — is central to the appeal of the approach.
The Science Behind BAETA and Other Upcycled Sorbents
At the chemical level, the trick is to cleave the PET polymer and attach amine groups that bind CO₂ strongly. The Copenhagen team used ethylenediamine to access a bis-aminoamide (BAETA) and related oligomers. These nitrogen-containing molecules chemically react with CO₂ to form stable adducts that can be heated to release concentrated CO₂ for storage or use. Because BAETA remains thermally stable up to roughly 220–250°C, it can operate across the temperature range typical of many flue gases, making it compatible with existing industrial exhaust streams. The study also suggested that BAETA is selective for CO₂ over nitrogen and retains its performance through multiple capture–release cycles.
BAETA joins a growing literature showing that waste plastics — when treated correctly — can become useful adsorbents. Other teams have converted PET and mixed plastics into activated carbons or doped porous carbons that capture CO₂; reported performances vary with synthesis method but often fall in the 1.6 to 4.0 mmol per gram range (equivalently 1.6–4.0 moles per kilogram) for laboratory samples. A feasibility study from the University of Aberdeen and peer-reviewed reports in Green Chemistry show that microwave activation, chemical activation and nitrogen-doping are among the routes used to tailor pore structure and surface chemistry for CO₂ uptake. These prior findings show the concept is robust across different chemical routes and that PET is a viable feedstock for multiple sorbent types.
Below is a short comparison harvested from the scientific literature to help readers judge the scale of the effect.
| Material (from waste PET) | Reported CO₂ uptake |
|---|---|
| BAETA (aminolysis product) | 3.4 mol/kg (max, lab) |
| Microwave-activated mixed-plastic activated carbon | ~1.62 mmol/g (dynamic) |
| PET-derived porous carbon (KOH activated) | up to 2.31 mmol/g (at 30°C, 1 bar) |
(Notes: mmol/g values equal mol/kg numerically — e.g., 1.62 mmol/g = 1.62 mol/kg. Laboratory values are sensitive to measurement conditions such as temperature, pressure and CO₂ concentration.)
Real-World Tests and Why Scale Matters
Laboratory performance matters, but implementation depends on logistics: Can you collect the plastic, convert it without huge energy inputs, and operate the sorbent under industrial conditions? The Copenhagen team addressed some of these questions in their paper and press coverage. They ran aminolysis on a kilogram of untreated consumer PET, tested material stability at elevated temperatures, and deliberately fed the reaction a mix of common household wastes to show the procedure tolerates impurities. Yields dipped, but the chemistry still produced BAETA-rich products. These steps were intended to demonstrate operational robustness before seeking scale-up partners.
Other research groups have explored complementary parts of the chain. Feasibility studies—such as one by the University of Aberdeen on converting household mixed plastics into activated adsorbents—have shown that microwave activation can increase uptake compared with conventional activation, and that adding nitrogen (via melamine doping) enhances CO₂ affinity, a useful property for capturing emissions from air or diluted flue gases. The study also highlights energy and water trade-offs: producing activated carbon often requires heat and activating chemicals (e.g., KOH), and life-cycle analyses caution that these inputs can erode climate benefits unless optimised. Reviews in energy and materials journals likewise recommend careful life-cycle accounting before declaring any pathway carbon-negative.
Why does scale matter in climate terms? The University of Copenhagen paper notes that models suggest carbon dioxide removal (CDR) capacities of 1.5 to 2.6 billion tonnes per year will be needed to reach net-zero pathways. Producing sorbents at the million-tonne scale would therefore be necessary if a significant share of CDR is to come from solid sorbents derived from waste feedstocks. This means any sorbent approach must also consider resource availability, production energy, and end-of-life management to be credible at that scale.
At the human level, the work has already affected both those in the lab and those managing waste.. The researchers emphasise that turning low-value, polluted streams into a saleable climate material could create new incentives for collecting plastics — including hard-to-recycle fractions that now go to landfills or the oceans. “If we can get our hands on the highly decomposed PET plastic floating in the world’s oceans, it will be a valuable resource for us,” one co-author said, which shows that cleanup programs and circular markets can reinforce each other. That is a practical reality: cleaner feedstocks cost less to process, and a market for upcycled sorbent could subsidise collection.
What this Means and Practical Next Steps
These findings matter because they sketch a path where plastic waste is not just a disposal headache but a feedstock for climate action. That said, several practical hurdles must be overcome before the lab novelty turns into wide deployment.
First, we still recycle only a small portion of global plastic. A number of global reviews and datasets show that only about 9% of plastic waste worldwide is ultimately recycled, with the rest incinerated, landfilled or mismanaged — a stubborn reality that underlines the scale of the feedstock challenge as well as the potential upside if new markets grow. According to the OECD/Our World in Data analyses, current recycling rates are low while production continues to rise.
Second, any upcycling pathway needs a favourable life-cycle balance. Earlier work converting PET to activated carbons warned that chemical activation and high-temperature steps can consume substantial energy and chemicals, which can reduce — or even reverse — the climate benefits unless the process is optimised and powered with low-carbon energy. A careful life-cycle assessment should be part of any scale-up plan. Peer-reviewed feasibility studies and reviews recommend transparent LCA and pilot demonstrations of full chains: collection → conversion → deployment → regeneration/reuse.
Third, investors and industry will want data on durability, regeneration energy and economics. The Copenhagen BAETA material scored well on thermal stability and multi-cycle performance in lab tests; the authors argue it can be pelletized for packed-bed industrial units and used at higher temperatures than aqueous amines, reducing solvent losses and corrosion. Still, plant-level pilots are the critical next step: scale the chemistry to tonnes, test the sorbent in real flue gas streams, capture and verify CO₂ purity and demonstrate repeated regeneration at plant conditions. The authors and press coverage say they are seeking partners and investment to take that step.
Practical actions for policymakers, funders and practitioners include: fund pilot projects that pair waste-collection programmes with conversion facilities; require and fund life-cycle studies as part of demonstration grants; and encourage cross-sector partnerships so plastic collection, chemical engineering and carbon storage experts work together. For communities, municipal waste managers and NGOs, the near-term opportunity is to seek collaborations with researchers and to document feedstock availability and contamination rates — local data matters when deciding which conversion route (chemistry vs pyrolysis to carbon vs activation) is most appropriate.
Conclusion and the Bigger Picture
Technologists cannot assume chemistry alone will solve plastic or climate crises. Reducing plastic production, improving design for recycling, and strengthening collection systems remain critical. But turning waste into a tool for climate mitigation — particularly when supported by robust life-cycle accounting and real industrial pilots — could be a meaningful piece of a larger circular-climate strategy. The Copenhagen work shows it is scientifically possible; the rest is engineering, policy and market building.
