Advanced Treatment Technologies for Heavy Metal Removal from Water and Wastewater: A Comprehensive Review

The pollution of water bodies with heavy metals presents a significant threat to both the environment and human health because of their harmful, long-lasting, and bioaccumulating properties. As industrialization continues to grow alongside stricter environmental regulations, there is an increasing need for effective and sustainable treatment solutions. This review thoroughly investigates both traditional and advanced techniques for the removal of heavy metals from water and wastewater, including chemical precipitation, adsorption, membrane filtration, electrodialysis, ion exchange, electrochemical methods, ion flotation, and photocatalysis. Each method is carefully analyzed regarding its mechanism, effectiveness in removal, operational requirements, advantages, and drawbacks. Adsorption and membrane-based technologies are noted for their high efficiency and adaptability, particularly when employing low-cost or nano-enabled materials. Chemical precipitation and coagulation–flocculation remain effective for treating high-concentration wastewater, while ion exchange is especially appropriate for the removal of trace amounts of metals. New techniques such as photocatalysis and electrochemical solutions present promising options but encounter challenges concerning scalability and cost. The review highlights that no single approach is the best fit for every situation; instead, the choice of method should consider factors like wastewater composition, metal concentration, environmental impact, and economic viability. By summarizing current research, this paper offers a critical evaluation of existing methods and identifies potential future innovations in heavy metal remediation, stressing the importance of developing eco-friendly, cost-effective, and scalable solutions to protect water resources.