Preparation of β-cyclodextrin/graphene oxide and its adsorption properties for methylene blue

Graphene oxide (GO) and GO-based materials have shown excellent adsorption properties because of bounteous structure and rich oxygen functional groups. Many studies have shown that GO are utilized as adsorbents to remove organic dyes from wastewater. GO was prepared by modified Hummers method using graphite powder as raw material. On this basis, β-cyclodextrin/graphene oxide composite (β-CD/GO) was prepared by modifying graphene oxide via β-cyclodextrin(β-CD) crosslinking method. GO and β-CD were characterized by Fourier transform infrared spectroscopy (FT-IR), energy-dispersive X-ray (XRD), scanning electron (SEM) and thermogravimetric analysis (TGA). Their adsorbents properties have been studied with methylene blue (MB) as adsorbate. The factors affecting the study include the temperature, adsorption time, amount of adsorbent and system pH value. Adsorption isotherm and kinetics of the adsorption process are systematically analyzed. The results show that β-CD/GO has a different adsorption capacity from GO under the same adsorption factors. Under the optimized conditions (the reaction temperature is 70 °C, the reaction time is 60 min and the concentration of adsorbent is 0.04 g/L), the removal efficiency of β-CD/GO is 20% higher than that of GO from 70% to 90%. The maximum adsorption capacity of β-CD/GO is 76.4 mg/g. β-CD/GO can be effectively regenerated by elution with absolute alcohol. In these tests, β-CD/GO was suggested to be more efficient than GO in the removal of organic dyes.