Water treatment technologies in removing heavy metal ions from wastewater: A review

Abstract

The scarcity of clean water resources leads to many scientific and technological advancements in wastewater treatment processes. The recalcitrance of heavy metals in wastewater has been proven to be a challenging concern. Therefore, there is a need for more water treatment technologies to completely remove heavy metals down to a non-hazardous level. In this article, current development in recent waste-water treatment technologies to remove heavy metals has been reviewed and summarized. This review evaluates the state-of-the-art removal processes, including chemical precipitation, photocatalysis, flotation, ion exchange, remediation, electrochemical treatment, adsorption, membrane technologies, and coagulation/flocculation. These processes are leading technologies with industrial efficiency and practical feasibility. In general, the key factors in selecting the most appropriate process for wastewater treatment are the cost required and characteristics of wastewater plus the applicability of the process.