Preparation and Characterization of Magadiite–Magnetite Nanocomposite with Its Sorption Performance Analyses on Removal of Methylene Blue from Aqueous Solutions

The magadiite–magnetite (MAG–Fe(3)O(4)) nanocomposite has great potential applications in the field of biomaterials research. It has been used as a novel magnetic sorbent, prepared by co-precipitation method. It has the dual advantage of having the magnetism of Fe(3)O(4) and the high adsorption capacity of pure magadiite (MAG). MAG–Fe(3)O(4) was characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and vibrating sample magnetometer (VSM). The results showed that Fe(3)O(4) nanoparticles were deposited on the interlayer and surface of magadiite. MAG–Fe(3)O(4) was treated as an adsorbent for methylene blue (MB) removal from aqueous solutions. The adsorption properties of MAG–Fe(3)O(4) were investigated on methylene blue; however, the results showed that the adsorption performance of MAG–Fe(3)O(4) improved remarkably compared with MA and Fe(3)O(4). The adsorption capacity of MAG–Fe(3)O(4) and the removal ratio of methylene blue were 93.7 mg/g and 96.2%, respectively (at 25 °C for 60 min, pH = 7, methylene blue solution of 100 mg/L, and the adsorbent dosage 1 g/L). In this research, the adsorption experimental data were fitted and well described using a pseudo-second-order kinetic model and a Langmuir adsorption isotherm model. The research results further showed that the adsorption performance of MAG–Fe(3)O(4) was better than that of MAG and Fe(3)O(4). Moreover, the adsorption behavior of MB on MAG–Fe(3)O(4) was investigated to fit well in the pseudo-second-order kinetic model with the adsorption kinetics. The authors also concluded that the isothermal adsorption was followed by the Langmuir adsorption isotherm model; however, it was found that the adsorption of the MAG–Fe(3)O(4) nanocomposite was a monolayer adsorption.