Synthesis and application of polyethyleneimine (PEI) -based composite/nanocomposite material for heavy metals removal from wastewater: A critical review

Toxic heavy metals released into the environment without treatment would contaminate the water quality and persistence in the environment. Recently, the polymer polyethyleneimine (PEI) is used for the chelation of heavy metal ions due to the strong chelating property, hydrophilic nature, and plenty of amine groups on its macro-molecular chain. The synthesis of PEI-based composite/ nanocomposite materials had been attracted much con-sideration for the removal of toxic heavy metals because of their unique properties, such as high affinity, metal binding, thermal stability, mechanical strength, and reusability potential. Moreover, the amine functional group in PEI provides a significant contribution to the adsorption of cationic and anionic heavy metals ions effectively. Until now, numerous publications on PEI-based composite/nanocomposite materials for the removal of heavy metals had been reported. However, there is a gap in the critical review of their synthesis strategy and appli-cation for toxic heavy metals treatment from wastewaters. This review provides a comprehensive review of the synthesis strategy, heavy metals removal efficiency, and regeneration potential of PEI-based composite materials. It also presents the advantages and the possible drawbacks of them need for further research development.