Recent progress in removal of heavy metals from wastewater: A comprehensive review

The heavy metal pollution constitutes a critical environmental issue. This has stimulated intensive efforts to develop treatment techniques for their removal from wastewater, including adsorption, membrane separation, precipitation/electrodeposition, ion exchange, coagulation-flocculation, flotation/electroflotation, solvent extraction, catalysis, and bioremediation. This article provides a comprehensive review on the advances in those techniques with the focus on the recent decade (2013-2023). It shows that the adsorption has attracted the most attention and membrane filtration the second, followed by precipitation and ion exchange. Interests in bioremediation and electrochemical treatments as well as catalysis are expected to increase in the future. Furthermore, the combination of different processes is a promising strategy to develop efficient hybrid technologies.