Preparation and characterization of magnetic Fe3O4@sulfonated -cyclodextrin intercalated layered double hydroxides for methylene blue removal

Nanocage structures derived from sulfated -cyclodextrin (SCD) intercalated MgAl layered double hydroxides (MgAl-NO3 LDHs) were prepared through ion-exchange reactions. Coprecipitation method was used to prepare the composites of magnetic Fe3O4@sulfonated -cyclodextrin intercalated LDH (Fe/SCD-LDH), which was demonstrated having an efficient adsorption capability to cationic pollutants and an excellent reuseability. X-ray diffraction and Fourier transform infrared spectroscopy confirmed that SCD was intercalated successfully and the basal spacing was expanded to 1.63nm. N-2-adsorption/desorption and scanning electron microscopy displayed that the resulting Fe/SCD-LDH possessed high crystallinity, hierarchical structure as well as large specific surface area. Energy-dispersive X-ray spectroscopy was used to investigate the type and content of the elements in Fe/SCD-LDH. Batch adsorption experiments were carried out to investigate the removal of methylene blue (MB) from aqueous solution using Fe/SCD-LDH as the adsorbent. MB was selected owing to its toxic and carcinogenic features as a kind of cationic dye. The adsorption process could be well described by the pseudo-second-order kinetic model and fitted well with the Langmuir isotherm model.