Crescentia cujete fruit shell as green and efficient coagulant for water purification

Conventional drinking water treatment facilities employ coagulants, typically alum and ferric sulfate to remove turbidity and improve the clarity of the water. While alum for example, is naturally occurring and has no known health hazards when used in the right amount for water treatment, there is growing concern about the sustainability and environmental impacts of these inorganic coagulants. To explore a cost-effective, sustainable, and eco-friendly alternative, we investigated the shell of calabash fruit (Crescentia cujete) as a plant-based natural and eco-friendly coagulant. Although the plant has been extensively studied for its medicinal purposes this is the first report of its potential use as a coagulant in water treatment. Using Jar Test experiments and statistical analysis, we found that the coagulant obtained from Crescentia cujete was able to reduce the turbidity of the water by 84.3% at an optimal dosage of only 1.0 g/L. Zeta potential and particle size diameter were determined using Zetasizer Nano ZS (Malvern Instruments Ltd., UK) and found to be −3.42 mV and 2.55 × 10⁴ d.nm respectively. The plant sample was further characterized via FT-IR analyses and was found to be largely composed of hemicellulosic materials, which likely contributed to the effectiveness of the coagulant.