Kinetic, Isotherm and Thermodynamic Studies for Removal of Methylene Blue Using β-Cyclodextrin/Activated Carbon Aerogels

A novel aerogel (beta-CD/AC) was prepared through polymerization reaction of beta-cyclodextrin (beta-CD) with activated carbon (AC) and vacuum freeze drying method. The structure and morphology of beta-CD/AC were characterized by scanning electron microscopy (SEM), Fourier transform infrared (FTIR) spectroscopy, Brunauer-Emmett-Teller (BET) method and thermogravimetric analysis (TGA). beta-CD/AC is used to deal with wastewater containing methylene blue (MB) dye. The effects of AC content in beta-CD/AC, pH value, temperature, contact time and amount of adsorbent on the adsorption of MB were studied in detail. The Langmuir and Freundlich adsorption models were applied to describe the equilibrium isotherms. The Langmuir monolayer adsorption capacity of MB onto beta-CD/AC was estimated as 166.67 mg/g. The kinetics of MB onto beta-CD/AC was well described by the pseudo-second order model. The thermodynamic parameters indicated that the adsorption reaction of MB onto beta-CD/AC was endothermic and spontaneous.