Researchers at the Institute of Science and Technology of the State University of São Paulo (ICT-UNESP) in São José dos Campos, Brazil, discovered that: moringa oleiferaCommonly known as moringa or white acacia, it may help remove microplastics from water.
The survey results are ACS OmegaJournal of the American Chemical Society.
Moringa is native to India and grows well in many tropical regions. Due to their high nutritional value, the leaves and seeds are widely consumed as food. Scientists have also studied the seeds for years for their potential role in water purification.
Moringa seed extract has similar effects as chemical treatments
“We showed that a saline solution extracted from the seeds performed similarly to aluminum sulfate, which is used in treatment plants to coagulate water containing microplastics. In more alkaline waters, it performed even better than the chemical product,” says Gabriel Bautista, lead author of the study. She conducted this research during her master’s degree program in the Postgraduate Program in Civil and Environmental Engineering (PPGECA) at the UNESCO Bauru School of Engineering (FEB).
The research was led by Adriano Gonçalves dos Reis, PPGECA professor at ICT-UNESP and FEB-UNESP. He is also responsible for the project “Direct and in-line filtration to remove microplastics from drinking water”, which is funded by FAPESP.
“The only drawback we have found so far with aluminum sulfate is an increase in dissolved organic matter, whose removal can make the process more expensive. However, in small-scale cases, such as rural properties or small communities, this method can be cost-effective and efficient to use,” says Reis.
How coagulation helps remove microplastics
The study focused on in-line filtration, a method in which water is first treated with a coagulant and then passed through a sand filter. This approach is best suited for waters with low turbidity. This means the water is relatively clear and requires fewer pretreatment steps.
Coagulation plays an important role because microplastics and other pollutants have a negative charge. This causes them to repel each other and not be easily captured during filtration. Coagulating agents such as moringa salt extract (which can be made at home) and aluminum sulfate neutralize these charges. As a result, the particles stick together and form large clusters that are easier to remove.
Previous studies by the same research group have shown that moringa seeds are effective throughout the entire processing cycle, including flocculation, sedimentation, and filtration. Luis Gustavo Rodríguez Godoy, the first author of this study, completed his master’s degree at FEB-UNESP with support from FAPESP.
Clinical testing of microplastic contaminated water
To evaluate this method, the research team added polyvinyl chloride (PVC) microplastics to tap water.
PVC was chosen because it is known to be mutagenic and carcinogenic, and is considered one of the most harmful plastics for human health. It is also commonly found on the surface of bodies of water and can persist even after conventional treatments.
The researchers exposed the PVC to ultraviolet light to simulate natural aging and better reflect the properties of real-world microplastics.
The contaminated water was then coagulated and filtered using a jar test system that mimics a small-scale water treatment process. The results were compared to samples treated using aluminum sulfate.
To measure effectiveness, the team used scanning electron microscopy (SEM) to count microplastic particles before and after treatment. They also used high-speed cameras and laser measurements to analyze the size of the particle clusters that formed. Both treatments showed similar levels of microplastic removal.
Test moringa in a real water source
Researchers are currently testing moringa seed extract in water taken from the Paraiba do Sul River, which feeds São José dos Campos. Results so far suggest that this method is also effective in treating natural water conditions.
“Aluminium- and iron-based coagulants are not biodegradable, have residual toxicity, and pose disease risks, leading to increased regulatory scrutiny and health concerns regarding their use. This has intensified the search for sustainable alternatives,” Reis concludes.
The findings highlight moringa as a promising and more sustainable option for reducing microplastics in drinking water, especially in small communities where cost and availability are key concerns.
