Graphene oxide (GOs) with different oxygen-containing functional groups was prepared by adjusting the amount of oxidant KMnO4. The effects of KMnO4 dosage on the structural characteristics

the type and content of the functional groups of GOs were analyzed by XRD

XPS

AFM and FTIR

and the performance of GOs on methylene blue (MB) were studied. The results indicated that KMnO4 dosage has a significant effect on the oxidation degree of GOs-n (n=2

3

4)

the maximum saturated adsorption capacity of MB+ was 728.44、965.63 and 807.29 mg·g-1

compared with Langmuir model fitted values of single molecular layer saturated adsorption capacity of standard deviation was 3.6%

3.7% and 4.2%

respectively. Pseudo-second-order kinetic model could better describe the dynamic process of adsorption

and R2 > 0.99

which based on GOs structure on the most abundant hydroxyl (-C-O-) and carboxyl (-COO-) as the main active sites with MB+ occur single molecular layer

exothermic and chemical speed control process. Adsorption heat was between 20-27 kJ·mol-1

and adsorption mechanism was dominated by ion exchange adsorption. Adsorption performance was positively correlated with the total amount of -C-O- and -COO- in GOs structure. Effects of epoxy groups and carbonyl groups on the adsorption capacity of MB by hydrogen bonding become prominent with increasing the extent of oxidation.