Magnetically separable functionalized graphene oxide decorated with magnetic cyclodextrin as an excellent adsorbent for dye removal

Abstract

Magnetic cyclodextrin/graphene oxide (MCGO) materials were fabricated through a facile chemical route and their application as excellent adsorbents for methylene blue (MB) was also demonstrated. The results from FTIR, SEM, TEM, VSM and XRD showed that MCGO was prepared. The large saturation magnetization (51.13 emu g⁻¹) of the synthesized nanoparticles allows fast separation of the MCGO from liquid suspension. The MCGO demonstrate extremely fast MB-removal from wastewater with a high removal efficiency within 50 min. The adsorption kinetics, isotherms and thermodynamics were investigated and indicate that the kinetics and equilibrium adsorption are well-described by pseudo-second-order kinetics and the Langmuir isotherm model, respectively. The results showed that, benefiting from the surface properties of graphene oxide, the hydrophobicity of cyclodextrin, and from the magnetic properties of Fe₃O₄, the adsorbent possesses quite a good and versatile adsorption capacity towards the dye under investigation. Most importantly, the adsorbent can be easily and efficiently regenerated for reuse with hardly any compromise of the adsorption capacity. The inherent advantages of the nano-structured adsorbent, such as high adsorption capacity, easy operation, rapid extraction, and regeneration, may pave a new, efficient and sustainable way towards highly-efficient dye pollutant removal in water and wastewater treatment.