Novel sodium lignosulphonate assisted synthesis of well dispersed Fe 3 O 4 microspheres for efficient adsorption of copper (II)

Abstract In this paper, the sodium lignosulphonate (SL) and sodium citrate (SC) as surfactants were applied to the synthesis of magnetite based on the solvothermal method. The synthetic conditions of Fe 3 O 4 -SL and Fe 3 O 4 -SC were optimized by L 16 (4 5 ) orthogonal experiment. The structural, morphological and magnetic properties of the samples were characterized by X-Ray Powder Diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FT-IR) and vibrating sample magnetometer (VSM). According to the results of the optimized samples, it can be found that the crystal regularity, dispersibility and morphology of the Fe 3 O 4 -SL are better than those of Fe 3 O 4 -SC. In addition, both remanent magnetization and coercivity of Fe 3 O 4 -SL were smaller than those of Fe 3 O 4 -SC based on VSM curve. It exhibited the apparent superparamagnetism. And the adsorption experiment of Cu 2 + on Fe 3 O 4 -SL was successfully carried out. The adsorption text results showed that the adsorption process can be well described by the pseudo second order kinetic equation, and the adsorption isotherms can be fitted by the Freundlich isotherm model.