Nature’s Filter: Evaluating Coconut Husk as a Low-Cost, Sustainable Material for Microplastic Removal in Water

Grade:

10

Teacher:

Alfred Santos

Microplastics, or plastic particles smaller than 5 millimeters, are now commonly found in water systems and present potential risks to both environmental and human health. As plastic breaks down and synthetic fibers shed, these particles enter rivers, oceans, and even drinking water sources. Conventional filtration materials can be costly or non-biodegradable, creating a need for more sustainable alternatives. This study investigated coconut husk fibers as a natural, low cost, and biodegradable filtration medium. The research focused on evaluating how effectively treated coconut husks can remove microplastics from water and whether repeated filtration increases removal efficiency. Coconut husk fibers were rinsed repeatedly with distilled water to remove impurities, then soaked in a sodium hydroxide solution and incubated for 48 hours to enhance fiber structure and adsorption capacity. Microplastics were produced by sanding a plastic bottle and collecting particles until a mass of 0.02 grams was obtained. These particles were mixed into 1000 mL of distilled water to create a standardized contaminated sample. The solution was passed through a syringe packed with treated coconut husk fibers, acting as a filter. Multiple filtration cycles were performed. After filtration, fibers were examined under a microscope to visually confirm particle capture, and filtered water samples were analyzed using a UV–vis spectrophotometer at 600 nm to measure absorbance as an indicator of turbidity and remaining particle concentration. Absorbance measurements decreased with each successive filtration cycle, indicating reduced turbidity and lower concentrations of suspended microplastics in the filtered water. Statistical analysis showed a strong negative linear relationship between number of filtrations and absorbance values (R² = 0.8088). Percent removal increased steadily across repeated passes, demonstrating improved filtration performance with multiple cycles. Microscopic observations also confirmed the presence of microplastic particles trapped within the coconut husk fibers. These findings indicate that treated coconut husk functions effectively as a natural filter for reducing microplastic content in water.

Project presentation

Research paper