Cerium as an Efficient Coagulant for Phosphorus Removal from Wastewater

Excessive nutrient levels, particularly phosphorus, in wastewater have led to severe environmental issues such as eutrophication, necessitating effective treatment methods for nutrient removal. Traditional coagulants like alum (Al2(SO4)3) are commonly used but often require high dosages and are sensitive to pH, limiting their effectiveness in varying wastewater conditions. Cerium, a rare-earth element, has emerged as a promising alternative coagulant due to its ability to remove nutrients efficiently across a wide pH range. This study investigates the performance of cerium in comparison to alum for phosphorus and organic matter removal. Cerium demonstrates superior performance, achieving up to 98.9% phosphorus removal at a lower dose (1.5 mg-Ce/mg-P) compared to alum (5.0 mg-Al/mg-P) while maintaining stable removal efficiency across both acidic and alkaline conditions. Furthermore, cerium also facilitates moderate organic matter (COD) removal, achieving up to 27.9% COD removal, enhancing overall water treatment performance. The main precipitate formed during the coagulation process is cerium phosphate (CePO4, 94% pure), which provides a stable, crystalline structure for nutrient capture. In conclusion, cerium offers a more efficient and cost-effective solution for wastewater treatment, reducing the need for pH adjustment and additional chemical inputs, while achieving higher phosphorus and organic matter removal compared to traditional coagulants.