Magnetic nanoparticles as effective adsorbents for the removal of heavy metals from water: a review of surface modification (2015-2022)

Abstract

The use of biopolymer composite materials in the usage of magnetic nanoparticles for the removal of heavy metal pollutants has received little attention, despite their remarkable physical and chemical properties that suggested their huge potential as promising adsorbents. . Therefore, various sorbents for heavy metals removal have been prepared including surface-modified magnetic nanoparticles (MNPs). MNPs are susceptible to oxidation in the air and agglomeration in solvents rendering them to lose their essential adsorbent properties. Silica coating has proven to prevent degradation of the MNP and functionalizes the surface with silanol groups. A fundamental understanding of various surface modifications would be beneficial for near future research as well as industrial applications. Thus, this article aims in reviewing the most recent advances for surface modification of MNPs materials, including biopolymer materials, focusing on the chemistry preparation, characterization, optimization, mechanisms of adsorption, isotherms and kinetic models in order to remove various metals in water.