Graphene oxide-Fe₃O₄ nanocomposite used as aniline adsorbent with a wide pH range

In this paper, the graphene oxide-Fe₃O₄ nanocomposite was prepared by introducing Fe₃O₄ and silane coupling agent containing sulfonic acid groups on the surface of GO. The morphology and structure of nanocomposites were characterized by a series of equipments, and the property of s-GO-Fe₃O₄ as aniline adsorbent was studied. The Fe₃O₄ particle is introduced to add magnetic property to GO magnetism and can eliminate the agglomeration of GO sheets. The addition of sulfonic groups improved the dispersion of nanocomposite and eliminated electrostatic repulsion. Thus, the nanocomposite shows high aniline adsorption capacity in a wide pH region and does not show high correlation with pH value. In addition, FTIR and XPS spectrum analyses showed that the adsorption of aniline by s-GO-Fe₃O₄ is the combined effects of π–π interaction, acid–base reaction, and hydrogen bonds. Furthermore, the adsorption of aniline of this nanocomposite follows the pseudo-second-order kinetic model and Freundlich isotherm model. Thus, s-GO-Fe₃O₄ is a promising nanosorbent for aniline removal from organic wastewater. Graphical abstract: [Figure not available: see fulltext.].