Plant-based coagulants for wastewater treatment: Recent advances and applications
Murendeni P. Ravele, Olalekan C. Olatunde, Opeyemi A. Oyewo, Seshibe Makgato, Damian C. Onwudiwe
Abstract
The increasing global demand for clean water and sustainable wastewater management has intensified interest in eco-friendly treatment technologies. Among these, plant-based coagulants have emerged as promising alternatives to conventional chemical coagulants due to their biodegradability, low toxicity, cost-effectiveness, and reduced sludge generation. This review presents a comprehensive overview of recent advances in developing, characterizing, and applying plant-based coagulants for wastewater treatment. It discusses the fundamental coagulation mechanisms, such as charge neutralization, polymer bridging, sweep flocculation, and double-layer compression. Furthermore, it highlights the bioactive compounds and functional groups responsible for coagulation activity in various plant species. Applications in treating textile, agricultural, tannery, oil mill, and emerging pollutant-containing wastewater are critically evaluated. Additionally, recent innovations, including hybrid systems, extraction and purification enhancements, and molecular modifications, are explored to improve the performance and stability of plant-based coagulants. Future perspectives emphasise standardization, genetic engineering, and commercial scalability to facilitate broader adoption. This review underscores the potential of plant-based coagulants as viable, sustainable solutions for modern wastewater treatment challenges.