Sunlight-Activated Water-Soluble Plastic Could Help Purify Water

Known as “Puribag,” this soluble material offers a solution to the massive use of plastics in Mexico—not only in bags, but also in product wrapping, containers, and labels that are discarded after a single use.

Mónica Valladolid

To help mitigate flooding caused primarily by improperly discarded plastic bags that end up clogging drains or contaminating waterways, students from the Unidad Profesional Interdisciplinaria de Energía y Movilidad (UPIEM) are developing a plastic material that dissolves in water and, when exposed to sunlight, purifies the surrounding liquid.

Delia Guadalupe Robles Galeana and Cristian Martínez Domínguez, eighth-semester students in the Energy Systems and Smart Grids Engineering program, are working on this plastic as an innovative solution that not only helps prevent flooding and environmental pollution but also enables the purification and reuse of collected rainwater.

According to Robles Galeana, more than 10 million plastic products are used every minute in Mexico, and any piece that ends up in a canal, river, or the ocean can take over a thousand years to degrade. In regions such as Mexico City and the State of Mexico, she noted, much of this waste accumulates in drainage systems, causing severe flooding.

In response to this challenge, Martínez Domínguez explained that they are developing a water-soluble, water-purifying plastic named Puribag.

“Puribag is a response to the excessive use of plastics in Mexico—not only in bags, but also in product wrapping, containers, and labels that are discarded, in most cases, after a single use,” he explained.

He added that in many households, people collect rainwater due to water scarcity or store water used for laundry. In such cases, placing a Puribag-based package into storage containers could help purify the water.

Multiple Collaborative Efforts

Developing a plastic that dissolves in water and purifies it through sunlight exposure has required extensive testing and the support of multiple institutions.

Among the collaborators involved in the development of Puribag are Universidad Autónoma Chapingo; the Centro de Investigación y de Estudios Avanzados (Cinvestav); the Centro de Investigación en Ciencia Aplicada y Tecnología Avanzada (CICATA), Legaria Unit; and the Institute of Biotechnology at UNAM.

As part of this process, Robles Galeana explained, the team has conducted various chemical analyses, which have already enabled them to identify both the photocatalyst—the substance that enables purification under sunlight—and the type of plastic most compatible with it. Looking Ahead The team behind Puribag estimates that within the next two years, they will complete the testing phase and be ready to manufacture their first product: plastic bags made from the new material.

“Producing the bag requires physicochemical and mechanical studies to determine whether it can withstand different weights and temperatures. We are currently carrying out those tests,” Martínez Domínguez said.

Did you know?

UPIEM students aim to achieve up to 70 percent purification of water collected after a shower by adding a Puribag-based package, which would help remove soap residues and harmful microorganisms.