Defluoridation from aqueous solution by manganese oxide coated graphene oxide

A new adsorbent manganese oxide coated graphene oxide (MOGO) was synthesized and characterized by TEM, XRD, FTIR, and BET analysis. The effects of different parameters such as pH, adsorbent dose, contact time and temperature were studied to understand the adsorption behavior of the adsorbent under various conditions. Adsorption studies revealed that optimum removal of fluoride occurred in a pH range of 5.5–6.7. The Langmuir isotherm model demonstrated that the maximum fluoride adsorption capacity of MOGO was 11.93 mg/g and 8.34 times higher than that of GO. The kinetic adsorption data were analyzed using the pseudo first-order model, the pseudo second-order model and the intra-particle diffusion model. Thermodynamic adsorption results showed that adsorption of fluoride by MOGO was a spontaneous and endothermic process.

TEM image (Fig. 1a) shows that GO film is transparent. Manganese oxide nanoparticles can be homogeneously doped on the surface of GO (Fig. 1b) by a chemical reaction of manganese acetate with KMnO4 in GO suspension.Figure optionsDownload as PowerPoint slideHighlights
► A new adsorbent manganese oxide coated graphene oxide was prepared.
► The maximum fluoride adsorption capacity of MOGO was 11.93 mg/g and 8.34 times higher than that of GO.
► Fluoride adsorption by MOGO was spontaneous and endothermic in nature.
► The optimum solution pH for fluoride removal was at ranges of 3.8–7.5.