Rapid adsorption of cationic dye-methylene blue on the modified montmorillonite/graphene oxide composites

Composite structure of montmorillonites(Mt)with graphene oxide (GO) or reduced graphene oxide (rGO) was successfully synthesized by grafting with 3-aminopropyl triethoxysilane (APTES) and hydrazine hydrate reduction. XRD, BET, FTIR, SEM and XPS analysis were used to characterize the surface and structure properties of the as-obtained products. Measurement results suggested that these two composites were similar in morphology and pore structure, but significantly different in the surface oxygenic groups. Adsorption properties of the Mt/GO and Mt/rGO were investigated using methylene blue (MB) as the target material. Compare to original Mt, APTES modified Mt and Mt/rGO, Mt/GO exhibited the highest adsorption capacity of 641.1 mg/g at the initial concentration of 750 mg/L, and MB was removed by 94.3% within 5min. Mechanism analysis suggested that the high absorption performance of the composite was determined by the high specific surface area, oxygenic groups of GO, high adsorption capacity of montmorillonite as well as the synergistic effect between the Mt and graphene oxide nanosheets.