Rapid adsorption of methylene blue on a graphene oxide-supported Fe-Mo nanomaterial: mechanism and application

A Fe-Mo/graphene oxide (GO) nanomaterial prepared by a simple reduction method was investigated in this study. This material demonstrated the ability to rapidly adsorb methylene blue (MB) from wastewater at different concentrations within 5 min, with a maximum adsorption capacity of 162 mg/g at 25 °C. Furthermore, as the temperature rises, the adsorption capacity of the Fe-Mo/GO material decreases slightly. The results of thermogravimetric analysis (TGA) also indicate that this material has good thermal stability at low temperatures. The detailed analysis using scanning electron microscopy (SEM), Fourier transform infrared (FTIR) spectroscopy, and X-ray photoelectron spectroscopy (XPS) revealed that the well-dispersed molybdenum in the Fe-Mo/GO nanomaterial is essential for the adsorption of methylene blue (MB). The adsorption behavior and equilibrium adsorption isotherm of Fe-Mo/GO nanomaterials align with the pseudo-second-order kinetic model and the Langmuir model, respectively. Compared with the single-functional Fe/GO material, this bimetallic composite not only addresses GO recovery issues but also improves the low adsorption rate typical of single-iron materials.