Direct synthesis of 3D flower-like maghemite particles and their properties

Magnetic iron oxides particles with three-dimensional (3D) flower-like structures have attracted much attention because of their unique properties and potential applications. However, finding a direct synthetic method to prepare maghemite (gamma-Fe2O3) particles with such specific shape is still a big challenge. In this work, we report a simple method for direct synthesis of 3D flower-like gamma-Fe2O3 particles using ferric nitrate (Fe(NO3)(3).9H(2)O) as a raw material and cetyltrimethyl ammonium bromide (CTAB) as a structure directing agent. The prepared samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), nitrogen adsorption/desorption measurements and magnetic measurements. The results confirm the formation of 3D flower-like gamma-Fe2O3 with a magnetization of 37.8 emu g(-1) and a Brunauer-Emmett-Teller (BET) surface area of 78.4 m(2) g(-1). It was found that the addition of CTAB has a great influence on the formation process and morphology of gamma-Fe2O3. Due to its porous hierarchical structure, the 3D flower-like gamma-Fe2O3 showed high adsorption ability for Congo red (CR), with a adsorption capacity of 102.7 mg g(-1) . Both pseudo-second-order kinetic model and Langmuir adsorption model can well describe the adsorption of CR onto 3D flower-like gamma-Fe2O3. (C) 2019 Elsevier B.V. All rights reserved.