Sulfhydryl modified β-cyclodextrin/Fe3O4/graphene oxide magnetic nanohybrid for the adsorption of silver ions and cationic dye methylene blue

Sulthydryl modified beta-cyclodextrin/Fe3O4/graphene oxide magnetic nanohybrid (S-CD/Fe3O4/GO-SH) was prepared using 3-mercaptopropyltrimethoxysilane functionalized beta-cyclodextrin/ Fe3O4/graphene oxide magnetic nanohybrid (beta-CD/Fe3O4/GO) fabricated by a one-step reversephase co-precipitation method. The obtained beta-CD/Fe3O4/GO-SH sample was characterized by transmission electron microscope, X-ray diffraction, Fourier-transform infrared spectroscopy, N-2 adsorption/desorption isotherm, X-ray photoelectron spectroscopy (XPS), thermogravimetric analysis and vibrating sample magnetometer. The adsorption property of beta-CD/Fe3O4/GO-SH for silver ions (Ag(I)) and cationic dye methylene blue (MB) in a single system was investigated by batch experiments. The results indicated that the beta-CD/Fe3O4/GO-SH as superparamagnetic adsorption material with magnetic separation property in aqueous solution was successfully prepared. The maximum adsorption capacity of the beta-CD/Fe3O4/GO-SH for Ag(I) and MB was 101.87 and 105.74 mg g(-1), respectively. The XPS analysis results affirmed that the sulthydryl groups of the beta-CD/Fe3O4/GO-SH displayed a superior affinity for Ag(I), and Ag(I) was reduced to Ag element during the adsorption process. The adsorption process of the beta-CD/Fe3O4/GO-SH for Ag(I) and MB conformed to the pseudo-second-order kinetic model representing the adsorption process as predominantly chemisorption. The adsorption equilibrium data of the beta-CD/Fe3O4/GO-SH for Ag(I) and MB had better agreement with the Freundlich isothermal model and the Langmuir model, respectively, indicating that the isothermal adsorption process of the beta-CD/Fe3O4/GO-SH for Ag(I) and MB was heterogeneous multilayer adsorption and homogeneous monolayer adsorption, respectively.