In the lab, Gabrielle Batista watched water laden with microscopic plastic particles flow through a simple filtration system. What emerged on the other side was cleaner—and the compound doing the work came not from a chemical plant, but from a seed used for centuries in traditional medicine. Batista, then a master's student at São Paulo State University, has helped demonstrate that extract from moringa oleifera seeds can remove microplastics from drinking water just as effectively as the aluminum sulfate used in municipal treatment plants, and in some cases, even better.
The findings, published in ACS Omega, emerged from the Institute of Science and Technology of UNESP in São José dos Campos, Brazil. The research team, led by Professor Adriano Gonçalves dos Reis, compared moringa seed extract against aluminum sulfate in laboratory tests using tap water contaminated with PVC microplastics. PVC was selected because it ranks among the most harmful plastics for human health, carrying mutagenic and carcinogenic properties, and it persists in water bodies even after conventional treatment. Both coagulants worked similarly well, neutralizing the negative electrical charge that causes microplastic particles to repel each other and clump into removable clusters. But when tested in more alkaline waters—a common condition in many natural sources—moringa extract actually outperformed its chemical counterpart.
"The saline extract from the seeds performs similarly to aluminum sulfate, which is used in treatment plants to coagulate water containing microplastics," Batista said. "In more alkaline waters, it performed even better than the chemical product."
The implications are significant. Aluminum and iron-based coagulants are widely used in water treatment, but they aren't biodegradable, leave residual toxicity, and have faced increasing regulatory scrutiny over health concerns. Moringa, by contrast, is native to India, grows readily in tropical regions, and its seeds can be processed into a coagulant at home with minimal equipment. Earlier research by the group, including work by Luiz Gustavo Rodrigues Godoy, showed the seeds remain effective across an entire treatment cycle—from initial flocculation through sedimentation and filtration.
The team is now testing their approach on water drawn from the Paraíba do Sul River, which supplies São José dos Campos and surrounding communities. Early results suggest the method holds up in real-world conditions, not just controlled lab settings.
Reis acknowledges one limitation: moringa treatment can increase dissolved organic matter, which might require additional processing in large-scale operations. But for smaller applications—rural homesteads, remote villages, communities where treatment infrastructure is limited—the cost and accessibility advantages could be transformative. "On a small scale, such as on rural properties and in small communities, the method could be used cost-effectively and efficiently," he noted.
As concerns about microplastic contamination in drinking water grow worldwide, a plant that grows in backyards across the tropics is emerging as a surprisingly powerful tool—and a reminder that answers to some of the world's most pressing problems may already exist in nature, waiting to be rediscovered.