Magnetic MnFe2O4–graphene hybrid composite for efficient removal of glyphosate from water

• This is the first application of graphene-based adsorbent for glyphosate removal from water.
• The magnetic character of the adsorbent makes it easily separable.
• A mechanism of glyphosate adsorption was proposed.

Reduced graphene oxide decorated with MnFe2O4 microspheres composed a hybrid composite (MnFe2O4–G) that was synthesized by a facile and green strategy involving immobilizing the MnFe2O4 microspheres on the graphene nanosheets via a simple one-pot solvothermal route. The composites were characterized using transmission and scanning electron microscopy, Fourier transformed infrared spectroscopy, X-ray diffraction, X-ray photoelectron spectroscopy and surface area measurements. It was demonstrated that the composite of single-layer graphene oxide with manganese ferrite magnetic microspheres exhibited adsorption properties for efficient removal of glyphosate from contaminated water. The as-prepared graphene manganese ferrite composite was tested for the adsorption of glyphosate by analytical methods under diverse experimental conditions. With respect to contact time measurements, the adsorption of glyphosate increased and reached equilibrium within 8 h at 25 °C with a maximum adsorption capacity of 39 mg g−1 at 5 °C. The Freundlich model and the pseudo-second-order kinetic model correlated satisfactorily to the experimental data. Thermodynamic studies revealed that the adsorption of glyphosate onto MnFe2O4–G was spontaneous, exothermic and feasible in the range of 5–45 °C. Therefore, the MnFe2O4–G hybrids synthesized in this research may offer an attractive adsorbent candidate for highly efficient removal of glyphosate from contaminated water for water treatment and purification processes.