A comprehensive review of recent advances in nanofiltration membranes for heavy metal removal from wastewater

Despite several technological advancements and achievements, wastewater treatment continues to be a fundamental global issue. The wastewater, which contains heavy metal ions, poses an acute threat to human health if not properly cleaned, making its disposal of paramount importance. Due to its adaptable design, efficient operation, and low cost, the nanofiltration (NF) membrane is one of the most successful methods for removing heavy metals from wastewater. NF membranes made from innovative materials are gaining popularity as a result of their many advantageous features, including their ability to treat wastewater in a variety of situations. To remove heavy metal ions from wastewater, the modification of NF membrane using interfacial polymerization (IP) and grafting techniques, as well as its subsequent development via nanofiller addition, is the most effective way to tailor the properties of NF membranes. Many aspects of NF membrane modification in terms of their preparation, characteristics, and performance have been introduced. This review discusses the modification processes and performances of NF membranes for heavy metal remediation from wastewater. The findings elucidated the roles and benefits of innovative membranes for the treatment of wastewater containing heavy metals. It has been observed that high rejection is enabled by electrostatic charge induction, the creation of chelating complexes and the tuning of pore size while the high permeability and antifouling properties can be achieved through the addition of hydrophilic nanofillers. The economical and non-toxic application of polyhydroxy phenols compounds for enhancing the permeability and capture rate of heavy metal ions is also suggested for study. Finally, the research gaps and uncertainties of these NF membranes in the treatment of water contaminated with heavy metals are highlighted.