Preparation of β-CD and Fe3O4 integrated multifunctional bioadsorbent for highly efficient dye removal from water

There is an interesting but challenging task to develop a facile and cost-effective procedure for the making of multifunctional bio-adsorbents for environmental applications. Herein, low-temperature solution-carbonized rice husk (RH-c), β-cyclodextrins (β-CD) and Fe 3 O 4 were synergically combined to prepare a new kind of multifunctional bioadsorbent, i.e . RH-c/Fe 3 O 4 /CD, and applied for the adsorption of methylene blue (MB) from aqueous solution. The structure, morphology and magnetic properties were characterized by powder X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FT-IR), 13 C nuclear magnetic resonance spectra (NMR), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), transmission electron microscopy (TEM) and vibrating sample magnetometry (VSM) techniques. Initial concentration of MB, contact time, pH effect, adsorption mechanisms and recycling test were also thoroughly investigated. The adsorption equilibrium data was best fitted by Langmuir isotherm model and the adsorption kinetics followed pseudo-second-order models for all samples. The maximum capacity predicted by the Langmuir model is 359.8 and 438.6   mg/g for RH-c/Fe 3 O 4 /CD and RH-c/CD2, respectively. The adsorption test suggested that resulting multifunctional RH-c/Fe 3 O 4 /CD is a promising bioadsorbent for dye molecules removal from aqueous system.