Studies of malachite green adsorption on covalently functionalized Fe3O4@SiO2–graphene oxides core–shell magnetic microspheres

Abstract This paper presents the synthesis of a novel core–shell covalently functionalized Fe 3 O 4 coated SiO 2 decorated graphene oxides (Fe 3 O 4 @SiO 2 –GO) adsorbent. The prepared Fe 3 O 4 @SiO 2 –GO was characterized by fourier transform infrared spectrum, X-ray diffraction(XRD), X-ray photoelectron spectroscopy (XPS), and magnetic measurements. And the adsorption properties of the Fe 3 O 4 @SiO 2 –GO toward malachite green were systematically investigated. Various factors possibly affecting the adsorption behavior (initial concentration, contact time, and adsorbent dosage) were also studied in detail. The adsorption capacity (q m ) of Fe 3 O 4 @SiO 2 –GO for malachite green was found to be 265.87 mg/g with best fit to Langmuir isotherm ( R 2  = 0.968), and the adsorption mechanism follows the pseudo-second-order model ( R 2  = 0.981). The results indicate that the Fe 3 O 4 @SiO 2 –GO adsorbent, which is easily separated via an external magnetic field, is a potential low-cost effective material for malachite green removal from contaminated water. Graphical Abstract