Construction of recyclable magnetic PEI-modified GO/Fe3O4 adsorbents for high-efficient removal of Cr(VI) ions from aqueous solutions

Cr(VI) is a highly hazardous water pollutant that poses significant risks to animals, plants, and humans. In this study, graphene oxide (GO) and polyethyleneimine (PEI) were incorporated into Fe3O4 via in-situ precipitation and hydrothermal methods. A new synergistic strategy was developed to enhance Cr(VI) removal by nitrogen/oxygen-containing functionalized magnetic recyclable PEI/GO/Fe3O4 (PMGO) composites, which had the optimum adsorption capacity of Cr(VI) being 148.98 mg/g. Experimental analysis confirmed that the excellent removal efficiency of PMGO on Cr(VI) in water environments was contributed to electrostatic interaction, reduction, and chelation. The adsorption mechanism was elucidated using pseudo-second-order kinetics and Langmuir isotherm models. PMGO exhibited a saturation magnetization intensity of 12.40 emu/g, facilitating rapid separation from water within 75 s. Cyclic tests further confirmed the cycling stability and reusability of PMGO, demonstrating its immense potential in effectively mitigating Cr(VI) contamination in aquatic environments. [Display omitted] •The maximum adsorption capacity of PMGO is 148.98 mg/g for Cr(VI).•The amino functional group in PEI served as an adsorption site for Cr(VI).•PMGO has good magnetic properties and recyclability.•Adsorption, reduction, and chelation were involved into Cr(VI) removal.