Young Argentines develop a device to capture microplastics

The most diverse synthetic fibers (most derived from plastic compounds) have become a common material in contemporary clothing. Whether to achieve colors and textures or to reduce the cost of clothing, what few know is that these fibers end up releasing microplastics when washed; and these microscopic structures end up contaminating waters, which are used for planting and human consumption. Exceedingly small, up to 5mm in diameter, microplastics take between 400 and 1000 years to disintegrate, and when they reach living beings, they lodge in their bodies and tissues, with harmful effects on health, although still little known.

This was one of the topics discussed in an online seminar open to the community held by Universidad del Sur, during the Covid-19 pandemic. When invited by chemistry teacher Walter Acosta to attend the activity, and observe how academic discussion activities are conducted, students Karla Bustamante, Agustín Mangüello, and Victoria Wesner decided that they needed to collaborate on the issue. Students of teacher Walter in the technical degree in chemistry at the Escuela de Educación Secundaria Técnica (EEST) Nº1 “Crucero A.R.A. General Belgrano”, from the city of Bahia Blanca, 650 km away from the capital, in Argentina, the students decided to advance in a scientific project capable of offering some kind of answer to the challenge.

Although he was familiar with Project Based Learning concepts, Walter had little practical experience in mediating student authorship activities. But when he was invited, he not only immersed himself in the experience but also profoundly transformed his teaching practices based on it. “My students taught me a lot with this activity. My practice was very content-oriented and this experience showed me the power of the approach via projects, Design Thinking, and STEM to transform the classroom,” he celebrates.

Mobilized by the literature, students began to build hypotheses about the consequences of microplastics on the environment and people. Since particles have already been found in the bloodstream of people and even in the placentas of pregnant women, students wondered what the possible long-term consequences of contamination in the human body would be: microplastics could impact the filtering functions of the human body, such as kidneys and liver? What are the possible consequences? Is there a particle limit to avoid more serious problems? “Our idea was for them to ask good questions, and outline hypotheses, even if they were not able to test or demonstrate them at this moment. And that’s exactly what STEM’s proposal is! Make students open their minds,” explains the teacher.

Once they reasoned that about 35% of microplastics found in water sources, plants, and animals came from washing clothes, the students decided that they needed to develop a kind of filter; low-cost and reusable, for washing machines.

Before defining the filtering compound, the students needed to build the apparatus that would hold it, allowing water to flow and “capture” the plastic microstructures. There were many drawings on paper, reviews of similar existing mechanisms, and projects in design software until reaching the prototype. To design the instrument in 3D, the students used Tinkercad, a free web application that allows the development of 3D projects, electronics, and coding. “As undergraduates in chemistry, they were not used to using tools from digital technologies; and they surprised me a lot, both with the speed with which they learned to use the application and with the quality and complexity of the design they developed,” explains the teacher. The printed prototype has a connection for the water inlet of the washing machine’s drain hose, and an outlet in its lower part. Detachable, the instrument can be reused in multiple washes and has sealing structures, preventing the possible loss of materials.

Focus on research: the importance of experimentation

As chemistry students, supervised by Walter, the group began to develop laboratory tests to test filter compounds, following the reference literature. After a series of experiments, they arrived at the use of activated charcoal as the best available option. Activated carbon has a very porous structure with a negative electrical charge, capable of attracting toxins and chemicals, such as microplastics. There were several experiments, which required, in addition to carrying them out, careful study and group discussion of the results. The students tested the compounds and their efficiency both in reducing sulfates and in the adhesion and reduction of microplastics in the water.

With the support of the mentorship of Samsung Solve for Tomorrow, students were able to advance in the systematic understanding of their invention for society. “It wasn’t just a product they were developing, but a response to a concrete environmental challenge, which profoundly impacts people’s lives,” explains Walter, calling attention to the importance of the empathic stage of the Project Track. “By actually experiencing the stage, the students took the issue as their own, wanting to solve it, embracing it,” he adds.

For the teacher, the mentoring support was also important to dynamize the group’s relationships, even training themselves as a mediator teacher. “As hard as I tried, I realized that the students in the classroom didn’t feel listened to as they did in activities like this one. I saw that the program’s mentor, Clara de Marcos, [coordinator of social and environmental innovation projects at Tekuoia, partner Solve for Tomorrow technique in the country] recognized the voice they had, encouraged them to see themselves, to perceive themselves as leaders, proponents of change,” he explains. He also emphasizes the importance of soft skills, especially collaboration. “They had to learn to work together, to recognize each other’s strengths, and that they needed support,” he argues

Although informal, monitoring the students gave Walter ideas to start an evaluation process, creating rubrics to monitor the knowledge acquired through learning through projects and the skills and attitudes they develop during the process. “I built markers, which I have been using in regular classes and, at the end of the process, my students started to fill in a questionnaire, identifying what they learned, what are the facilities and challenges of this type of proposal, what they need to improve, what I need to improve as a teacher, etc”, he explains , indicating that,  he believes this is the way to advance in the quality and relevance of educational processes for youth.