Cyclodextrin Functionalized Mesoporous Silica for Environmental Remediation of Methylene Blue Dye

Functionalization of mesoporous silica KIT-6 with β-cyclodextrin (β-CD) was successfully realized via post-grafting method as a new adsorbent for environmental remediation of methylene blue (MB) dye from aqueous solutions. The mesostructure properties were characterized by transmission electron microscope (TEM), low-angel X-ray diffraction (XRD), Fourier transform infrared (FT-IR), thermogravimetric analysis (TGA) and N₂ sorption isotherm. The remarkable adsorption of MB into β-CD-KIT-6 adsorbent was studied using UV-visible spectroscopy. The β-CD-KIT-6 exhibited higher adsorption capacity compared with unmodified-KIT-6. The adsorption behavior of MB into the β-CD-KIT-6 and unmodified-KIT-6 was carefully investigated using different kinetic and isotherm models. The adsorption process followed a pseudo-second order kinetic model and well-fitted to Langmuir isotherm. The thermodynamic parameters were evaluated and the adsorption of MB was found to be an exothermic and spontaneous process. The adsorption of MB into the β-CD-KIT-6 was highly dependent on the solution pH.