A problem transformed into raw material for a circular economy
In the quiet accumulation of discarded cigarette butts — one of the world's most overlooked pollutants — four secondary school students from Maia found not a nuisance but a question worth answering. Their project, ReAsh, transforms the cellulose acetate inside cigarette filters into functional materials like buttons, earning first place at Portugal's 2026 National Science Exhibition and an invitation to compete across Europe. It is a reminder that circular thinking often begins not in corporate laboratories but in the minds of young people willing to look at what others step over.
- Nearly 770,000 tons of cigarette butts accumulate globally each year, leaching toxins into soil and water while remaining almost entirely invisible as a policy or design problem.
- Four teenagers from Maia Secondary School disrupted that invisibility by partnering with university chemists to extract and repurpose the cellulose acetate hidden inside discarded filters.
- Their prototypes — functional buttons made from recovered waste — convinced a national jury of both technical rigor and real-world relevance, outcompeting over eighty projects from nearly two hundred young scientists.
- The team won €1,250 and will carry Portugal's flag to the EU Contest for Young Scientists in Kiel, Germany, in September 2026.
- ReAsh is not alone: sister projects from the same school are turning poultry waste into biopolymers and cigarette filters into wildfire-reforestation capsules, signaling a sustained movement rather than a single breakthrough.
Four students from Maia Secondary School spent months working in university laboratories to answer a question most people never think to ask: what if cigarette butts could become raw material? Their project, ReAsh, took first place at Portugal's National Science Exhibition in May 2026, besting more than eighty entries from nearly two hundred young competitors.
The scale of the problem they chose is staggering in aggregate even if invisible in daily life. Roughly 5.8 trillion cigarettes are smoked each year worldwide, leaving behind approximately 770,000 tons of discarded filters that break down slowly and leach toxins into soil and water. Alexandre Colaço, Carina Sousa, Mafalda Gama, and Mariana Cruz decided to treat that waste as a resource. Working with researchers at the University of Porto's Green Chemistry lab, they learned to safely extract cellulose acetate from collected butts and mold it into functional prototypes — including buttons — demonstrating the concept could scale.
The jury, convened at Porto's Electric Car Museum, recognized not only the technical achievement but the project's contribution to circular economy thinking. The team received €1,250 and an invitation to represent Portugal at the EU Contest for Young Scientists in Kiel, Germany, in late September 2026.
ReAsh was not the only story emerging from Maia Secondary that day. A companion project, PlumaFilm, earned an honorable mention for converting poultry waste into biopolymers, while a third project, B-Cycle, created biodegradable seed capsules from recycled filters filled with nutrient gel from food waste — designed to help reforest areas scarred by wildfires. All three projects grew from a formal partnership between the university's chemistry department and the Maia school district, connecting teenagers with active research labs and senior scientists. What began as a question about cigarette butts has become a model: young people doing university-level environmental science, and winning recognition for it.
Four students from Maia Secondary School spent months in university laboratories learning to turn cigarette butts into buttons. Their project, called ReAsh, won first place at Portugal's National Science Exhibition in May 2026, beating out more than eighty other entries from nearly two hundred young scientists across the country.
The problem they chose to solve is everywhere and almost invisible. Cigarette butts accumulate in gutters, parks, beaches, and forests—small enough to ignore individually, but staggering in aggregate. Globally, roughly 5.8 trillion cigarettes are smoked each year, leaving behind approximately 770,000 tons of discarded butts. These filters break down slowly and leach toxins into soil and water. Most people step over them without thinking.
Alexandre Colaço, Carina Sousa, Mafalda Gama, and Mariana Cruz decided to ask a different question: what if this waste could become raw material? They collected butts from their city, then worked with researchers at the University of Porto's Faculty of Sciences to understand the chemistry inside. The filters contain cellulose acetate—a material that, when properly extracted and cleaned, can be reshaped into solid objects. Under the guidance of Andreia Peixoto and doctoral student Inês Marques at the university's Green Chemistry lab, the team learned to recover this compound through a safe, environmentally responsible process. They then molded the recovered material into prototypes: functional items like buttons that demonstrated the concept could work at scale.
The jury that evaluated the work at the exhibition, held at the Electric Car Museum in Porto, was impressed by more than just the technical achievement. The judges noted the project's contribution to circular economy thinking—taking a problem and converting it into something with genuine value. They recognized its relevance to environmental responsibility and the quality of the finished product created within a school setting. The team received 1,250 euros and an invitation to represent Portugal at the European Union Contest for Young Scientists, scheduled for late September 2026 in Kiel, Germany.
The success of ReAsh was not an isolated moment for Maia Secondary. Another project from the same school, called PlumaFilm, earned an honorable mention for transforming poultry waste into innovative biopolymers. Students Rodrigo Seabra, Tiago Queiroz, Martim Sousa, and Paulo Sousa developed that work with support from the same university lab. A third project, B-Cycle, also backed by the university, took the cigarette-butt concept further: the team created biodegradable seed capsules from recycled filters, filled with nutrient gel made from food waste, designed to help reforest areas damaged by wildfires. That project won best poster at a biotechnology congress.
These results reflect a formal partnership between the university's chemistry department and the Maia school district—an agreement that connects secondary students with active research labs and senior scientists. The collaboration appears to be working. It bridges the gap between classroom learning and real investigation, giving teenagers access to equipment and expertise they would not otherwise have, while giving researchers a chance to mentor the next generation. The National Science Exhibition itself drew about two hundred competitors this year, organized by the Youth Foundation and the Porto city council. What began as four students asking what to do with cigarette butts has become a model worth watching: young people solving environmental problems with university-level science, and winning recognition for it.
Citas Notables
We envision a future where cigarette butts stop polluting our streets and ecosystems, transforming them into raw material for a circular and sustainable economy.— ReAsh student team
La Conversación del Hearth Otra perspectiva de la historia
Why cigarette butts? There are so many environmental problems to choose from.
They're everywhere and nobody thinks about them. You step over thousands in a year without noticing. But they don't disappear—they just sit there, leaching chemicals. The students realized that scale: 770,000 tons annually. That's the kind of number that stops you.
And the chemistry—how hard was it to actually extract the cellulose acetate and turn it into something usable?
Hard enough that they needed university labs and expert guidance. But that's the point of the partnership. The students didn't just read about it; they worked in the actual labs, learned the process, understood why it matters. They recovered the material safely, then proved it could be molded into real objects.
The buttons seem almost humble as an end product. Why not something more dramatic?
That's actually the strength of it. Buttons are ordinary, functional, something people use every day. It proves the material works for real applications, not just as a concept. And it's scalable—you could imagine factories doing this.
What struck the judges most?
They liked that the students took a problem and turned it into a solution with actual value. Not just environmental awareness, but circular economy thinking. They also noted it was done in a school context, which matters—this wasn't a lab with unlimited resources.
And now they're going to Germany to compete internationally?
Yes, in September. But what's interesting is this wasn't a one-off. The same school had two other projects recognized. It suggests something is working in how they're connecting students with real research.
What happens to ReAsh after Germany?
That's the open question. The prize money helps, but scaling from a school project to actual production is a different challenge. The real value might be in the model itself—showing that secondary students can do this kind of work.