Enhanced photocatalytic degradation of methylene blue and adsorption of arsenic( iii ) by reduced graphene oxide (rGO)–metal oxide (TiO 2 /Fe 3 O 4 ) based nanocomposites

Reduced graphene oxide (rGO) and metal oxide based binary (rGO–TiO 2 /rGO–Fe 3 O 4 ) and ternary (rGO–Fe 3 O 4 –TiO 2 ) nanocomposites with enhanced photocatalytic and adsorption properties are successfully synthesized by a simple one-step solvothermal process. The microscopy images of the nanocomposites show that the ferric oxide (Fe 3 O 4 ) and titania (TiO 2 ) nanoparticles are firmly anchored over rGO, which enhances the surface area of the resultant nanocomposites. The as-synthesized nanocomposites are evaluated for the removal of methylene blue dye under UV and visible light irradiation as well as for the adsorption of As( iii ) from aqueous solution. Compared to binary, the ternary (rGO–Fe 3 O 4 –TiO 2 ) nanocomposite exhibits the highest dye degradation efficiency (∼100% within 5 minutes). This enhancement is attributed to the synergetic interaction and increase in the surface area of rGO–Fe 3 O 4 –TiO 2 . For As( iii ) adsorption, the adsorption data are obtained by Langmuir and Freundlich adsorption isotherms. Compared to binary nanocomposites, the maximum monolayer adsorption capacity (147.05 mg g −1 ) is observed for rGO–Fe 3 O 4 –TiO 2 . These results reveal that the rGO–Fe 3 O 4 –TiO 2 nanocomposite has potential application in water/wastewater treatment.