Preparation of a novel Fe3O4/graphite oxide nanosheet/citric acid-crosslinked β-cyclodextrin polymer composite to remove methylene blue from water

A novel composite basing on the Fe 3 O 4 nanoparticle, the graphite oxide nanosheet (GON), and the citric acid-crosslinked β-cyclodextrin polymer (CA-CDP) was prepared for the purpose of removing the methylene blue (MB) dye from water. The structure of the resultant Fe 3 O 4 /GON/CA-CDP composite was investigated by the scanning electron microscope, the two dimensional EDS mapping, the thermal gravimetric analyzer, the Fourier transform infrared spectroscope, the wide angle X-ray diffraction, the X-ray photoelectron spectroscope, and the zeta potential measurement. The Fe 3 O 4 /GON/CA-CDP composite not only had a good MB adsorption capacity of 173 mg/g but also a high saturation magnetization of 36.4 emu/g. It was found that the MB adsorption capacity of the Fe 3 O 4 /GON/CA-CDP composite increased with the increasing initial MB solution pH value especially in the low-pH-value range. Moreover, the MB adsorption mechanism, the MB adsorption isotherm, and the MB adsorption kinetic of the Fe 3 O 4 /GON/CA-CDP composite were investigated. It was found that 1) the good adsorption ability of the Fe 3 O 4 /GON/CA-CDP composite for the MB dye originated from the electrostatic attraction, the Lewis acid-Lewis base interaction, the host-guest supramolecular interaction and the π-π interaction, and 2) the MB adsorption isotherm and the MB adsorption kinetic of the Fe 3 O 4 /GON/CA-CDP composite could be well explained by the Sips model and the intraparticle diffusion model, correspondingly.