Green Solutions: The Application of Plants in Water Purification: A Review

The need for safe and clean water is growing, which has increased the search for sustainable, low-cost, and eco-friendly purification methods. This review explores the application of plants as natural agents in water purification, emphasizing their potential as alternatives to conventional chemical coagulants and disinfectants. Traditional purification techniques such as chlorination, reverse osmosis, and alum-based coagulation, though effective, present environmental, economic, and health challenges including high operational costs, generation of toxic by-products, and potential health risks. In contrast, plant-based coagulants and bioflocculants derived from species such as Moringa oleifera, Opuntia ficus indica, Aloe vera, and Salvia hispanica offer biodegradable, nontoxic, and cost-effective solutions. The mechanisms involved include coagulation-flocculation, adsorption, rhizofiltration, and physical filtration, each contributing uniquely to the elimination of organic contaminants, pathogens, heavy metals, and suspended particles. Case studies from China and India, the United States, and Nigeria demonstrate successful implementation of plant-based purification systems in both natural and constructed wetlands. Despite challenges related to extraction methods, variability in plant efficacy, and large land requirements, ongoing research into nanotechnology, genetic modification, and plant–microbe interactions promise to enhance their efficiency and scalability. Overall, the use of plants in water purification aligns with global goals for sustainable water management, offering a green, accessible, and effective alternative for communities particularly in developing regions.