Could a simple plant seed become a powerful ally against microplastics in water?
Brazilian researchers have just shown that moringa seed extract removes these particles as well as, and sometimes better than, conventional chemical treatments. The secret? A surprising natural property: moringa proteins cause microplastics to clump together, making them easy to remove by filtration.
Microplastics, those tiny plastic fragments, are a growing source of pollution. They often pass through wastewater treatment plants and end up in tap water. Current methods use aluminum or iron salts to coagulate them, but these chemicals are not biodegradable and can leave toxic residues.
Illustration image Pixabay
The search for more sustainable solutions has led scientists to explore natural alternatives, such as moringa seeds, already known for their purifying properties. A study published in
ACS Omega confirms their effectiveness against microplastics.
The researchers tested a saline extract of moringa seeds. Added to water, it neutralizes the negative charge of microplastics, which normally repel each other. This forces them to form larger clumps, which are then trapped by a sand filter. In the lab, moringa extract matched the performance of aluminum sulfate, and in more alkaline water, it even outperformed it.
To mimic real-world conditions, the team added PVC microplastics to tap water and aged them with ultraviolet rays. PVC is particularly dangerous because it can be mutagenic and carcinogenic. The contaminated water was treated in a Jar Test system, simulating a treatment plant. Measurements using electron microscopy showed that moringa extract removed as many microplastics as aluminum sulfate, with clumps of similar size.
Moringa seed: the saline extract produced the necessary coagulation to filter microplastics.
Credit: Adriano Reis/ICT-UNESP
The next step was to test the method on water from the Paraíba do Sul River, which supplies São José dos Campos. Initial results show that moringa extract also works under real conditions, even with natural impurities. The researchers highlight health concerns related to aluminum-based coagulants, which are non-biodegradable and toxic. Moringa offers an eco-friendly and safe alternative.
For small communities and rural areas, this method could be both economical and simple to implement. The extract can be prepared at home without specialized equipment. Although large plants still use conventional chemicals, moringa could fill a need where sustainability and low cost are priorities.
The study was conducted by researchers at São Paulo State University, with support from FAPESP. They continue to optimize the process and explore other natural coagulants. The results indicate that moringa could become a valuable tool in the fight against microplastics, especially in regions where access to advanced treatment is limited. Further work is needed to scale up, but the initial data is encouraging.