Magnetic nanoadsorbents derived from magnetite and graphene oxide for simultaneous adsorption of nickel ion, methylparaben, and reactive black 5

Abstract

The purpose of this study was to investigate magnetic nanoadsorbents (GO/Fe3 O4) derived from magnetite (Fe3 O4) and graphene oxide (GO) for simultaneous removal of nickel ion (Ni(II)), meth-ylparaben (MP), and reactive black 5 (RB5). As a result, the maximum adsorption capacity in aqueous solution for Ni(II), MP, and RB5 was 15.5, 20.69, and 63.18 mg g−1 in single-component system, respectively. The adsorption of Ni(II), MP, and RB5 onto GO/Fe3 O4 reveals good agreement with the Langmuir adsorption isotherms and pseudo-second-order model. The adsorption capacity suppressed for MP with increasing RB5 concentration in MP–RB5 binary system. However, the adsorption capacity for Ni(II) almost was not affected with increasing MP and RB5 concentration in binary system. The mechanisms of GO/Fe3 O4 for the adsorption of Ni(II), MP, and RB5 are prob-ably dominated by π–π interaction, electrostatic attraction, both π–π interaction and electrostatic attraction, respectively. The optimum ethanol concentration to desorb methylparaben from GO/Fe3 O4 is 95% with a three times adsorption–desorption cycle by the recovery of magnetic force due to the detachment of the shell (graphene). Conclusively, GO/Fe3 O4 has good adsorption performance and is easily reused; these are important factors contributing to its potential practical application.