Researchers have discovered that seeds from the moringa tree, also known as the white acacia, can effectively filter microplastics from drinking water. The seeds, when processed into a saline extract, coagulate water containing microplastics, causing them to clump together for easy removal.
The study, led by Gabrielle Batista from São Paulo State University, found that the moringa seed extract performs similarly to aluminum sulfate, a common chemical coagulant used in water treatment plants. In more alkaline waters, the natural extract even outperformed the chemical alternative.
Coagulation is a key step in water treatment, as it neutralizes the negative electrical charge on microplastic particles, allowing them to aggregate and be filtered out. Professor Adriano Gonçalves dos Reis, who coordinated the research, highlighted the growing health and environmental concerns over aluminum- and iron-based coagulants, which are non-biodegradable and leave residual toxicity.
The team tested the moringa seed treatment on tap water contaminated with polyvinyl chloride (PVC) microplastics, known for their mutagenic and carcinogenic risks. The PVC was artificially aged using ultraviolet radiation to mimic natural degradation. After coagulation and filtration using a Jar Test device, scanning electron microscopy showed no significant difference in particle removal compared to aluminum sulfate.
The researchers are now testing the moringa seed extract on river water, with promising results so far. The moringa tree is already widely used for its nutritious leaves and seeds, and this study suggests a new, sustainable application for water purification.
