Fabrication, Modification, and Mechanism of Nanofiltration Membranes for the Removal of Heavy Metal Ions from Wastewater

Heavy metals present in wastewater and water scarcity are a global challenge worldwide. The elimination of heavy metals in wastewater is necessary to protect the ecosystem and human health. Heavy metals such as lead, cadmium, and mercury are among many other toxic heavy metals present in wastewater. There are several conventional methods that have been implemented to mitigate heavy metal pollution in wastewater and according to literature, it has been evident that the nanofiltration (NF) separation technique requires minimal pressure to obtain high rejections of multivalent inorganic salts compared to conventional methods. NF separation process is highly competitive in terms of selectivity and cost-benefit. The growing research trend of NF fabrication and modification collates that the technology has been applied in various industrial and municipality wastewater treatment facilities. The review paper aims to illustrate the health impacts of heavy metal exposure, the cons of conventional methods and the utilization of NF membranes in wastewater treatment, the overall factors affecting membrane performance, and future aspects of the separation techniques. The presence of heavy metals in wastewater poses a serious health risk and has a severe impact on the environment. Membrane separation technology has proven to be the most effective technology that can remove almost all types of contaminants present in water and research in this area has grown in the past decade. This review demonstrates the negative effects of water pollution and applicability of nanofiltration membranes in water treatment for removing heavy metals. Minimum disadvantages are encountered from the membrane technology integration into water treatment applications. Nanofiltration membrane technology are distinguished by their low rejection of monovalent ions, strong rejection of divalent ions, and increased flux. Nanofiltration membranes can be employed in a variety of applications including water and wastewater treatment. The integration of advance membrane technology into water treatment facilities will be beneficial for the economy, energy usage and water sustainability.image