In a laboratory in São José dos Campos, Brazil, researchers found that an extract from moringa seeds removed up to 98 percent of aged PVC microplastics from drinking water in tests, matching or exceeding the performance of aluminum sulfate, a standard chemical coagulant used in treatment plants.
The study, published in ACS Omega and led by Gabrielle Batista during her master’s research at UNESP, focused on Moringa oleifera, a plant native to India that now grows across tropical regions. Scientists tested the saline extract from moringa seeds against aluminum sulfate in an in-line filtration process designed for low-turbidity water. In neutral conditions, the plant-based extract performed similarly to the chemical coagulant. In more alkaline water, moringa outperformed aluminum sulfate, removing a greater share of the microplastic contaminants.
Microplastics, defined as plastic particles under five millimeters, have accumulated in global water systems for decades from sources including car tires, synthetic textiles, and degraded packaging. These particles pose health risks given that they can pass through intestinal walls into the bloodstream and organs, potentially contributing to cancer, heart disease, and reproductive issues. They too act as carriers for other hazardous pollutants, moving toxins up the food chain.
Current water treatment in Europe relies on physical and chemical methods, with aluminum sulfate—commonly called alum—being a primary coagulant. While effective at binding microplastics for removal, alum carries drawbacks. Its production requires strip-mining bauxite in tropical regions such as Australia, Brazil, and Jamaica, leading to deforestation and habitat loss. The refining process consumes significant thermal energy, generating greenhouse gas emissions. In use, alum can elevate aluminum levels in water, a factor linked in some studies to neurological disorders like Alzheimer’s disease. It also produces large volumes of sludge that are difficult to dispose of safely, often ending in landfills where they may leach toxins.
The moringa alternative avoids many of these issues. The tree grows rapidly, resists drought, and thrives in poor soils with minimal water or fertilizer. It acts as a carbon sink and supports biodiversity. Its seeds, already used for nutrition and traditional medicine, can be processed into a saline extract that requires no industrial refining. Researchers note the extract can be made at home, offering potential for decentralized use in rural or small-community settings where infrastructure is limited.
Adriano Gonçalves dos Reis, the project lead and professor at ICT-UNESP, highlighted that while aluminum sulfate can increase dissolved organic matter—raising treatment costs—the moringa method showed no such drawback in their tests. He emphasized its cost-effectiveness and efficiency at small scale, though broader implementation would require adaptation to varying water chemistries and existing treatment plant designs.
The use of moringa for water purification is not new. Historical accounts suggest Ancient Egyptians used the seeds to clarify water and reduce turbidity. What is novel is the rigorous validation of its efficacy against modern pollutants like PVC microplastics, one of the most persistent and harmful types due to its additives and resistance to degradation.
Researchers caution that while lab results are promising, scaling the method to municipal treatment plants will require further study on flow rates, long-term stability of the extract, and integration with existing coagulation-flocculation-sedimentation-filtration cycles. The team noted earlier work confirming moringa’s effectiveness across all stages of conventional treatment, not just initial coagulation.
As the EU strengthens monitoring of microplastics in drinking water following 2024 protocol updates, the search for sustainable alternatives to chemical coagulants intensifies. Moringa offers a plant-based option that could reduce reliance on energy-intensive, environmentally damaging processes—provided field trials confirm lab findings and economic models support wider adoption.
How does moringa seed extract remove microplastics from water?
The extract neutralizes the negative electrical charge on microplastic particles, allowing them to clump together into larger masses that can be more easily trapped by sand filters during the coagulation stage of water treatment.
Is moringa seed extract safe to use in drinking water treatment?
The sources do not report any toxicity or safety concerns from using moringa seed extract in water treatment; the plant is already widely consumed for its nutritional value and used in traditional medicine.
Can moringa-based water treatment be used in large cities?
The researchers suggest the method is most promising for small-scale or rural applications due to current evidence, and note that adapting it for large municipal plants would require further study on scalability and integration with existing infrastructure.
What type of microplastics were tested in the study?
The researchers used aged polyvinyl chloride (PVC) microplastics, one of the most harmful types due to its prevalence and potential to carry toxic additives.
Related reading
