▎ 摘 要
This study describes an eco-friendly approach for the synthesis of beta-cyclodextrin functionalized graphene oxide (beta CD-GO) and its evaluation as adsorbent for removal of cadmium (Cd2+) and methylene blue (MB) from aqueous medium. Owing to a beta CD mass loading of similar to 15.3% on GO sheets, the as-prepared nanocomposite displayed superior thermal stability. Moreover, in spite of its fairly low Brunauer-Emmett-Teller specific surface area of 14.24 m(2) the pcD-Go composite demonstrated significantly high adsorption capacity toward both Cd2+ (117.07 mg g(-1)) and MB (323.98 mg g(-1)). The equilibrium data presented excellent fit to the Langmuir isotherm, implying monolayer adsorption of Cd2+ and MB onto beta CD-GO. The molecular mechanisms involved in the uptake of these pollutants were ion-exchange, electrostatic, hydrophobic and pi-pi interactions. Further, the uptake of Cd2+ and MB on beta CD-GO followed the pseudo-second order kinetics, and the rate of Cd2+ removal was faster than that of MB. Additionally, thermodynamic analysis revealed a spontaneous and endothermic nature of the adsorption process. Most importantly, the beta CD-GO composite did not show any significant drop in adsorption efficiency even after three adsorption-desorption cycles. Overall, our preliminary findings suggest that beta CD-GO merits further consideration for removal of dyes and heavy metals from wastewaters. (C) 2019 Elsevier B.V. All rights reserved.