Synthesis of water-dispersible graphene-modified magnetic polypyrrole nanocomposite and its ability to efficiently adsorb methylene blue from aqueous solution

• Fe3O4@PPy/RGO were fabricated through a facile chemical route for adsorption of dyes.
• The maximum adsorption capacity of Fe3O4@PPy/RGO for methylene blue removal is 270.3 mg g−1 at 30 °C.
• Sorption kinetic is fast and the data are in good agreement with pseudo-second-order kinetic model.
• The equilibrium adsorption data fitted the Langmuir isotherm well.
• Fe3O4@PPy/RGO can be easily separated from the water by external magnetic field.

A graphene-modified, magnetic polypyrrole nanocomposite (Fe3O4@PPy/RGO) was fabricated through a facile chemical route and its application as an adsorbent for the removal of a dye was also demonstrated. The as-prepared Fe3O4@PPy/RGO nanocomposite was characterized by Fourier transform infrared (FT-IR) spectroscopy, transmission electron microscopy (TEM), X-ray diffraction (XRD), N2 adsorption–desorption, and zeta potential analysis techniques. The Fe3O4@PPy/RGO nanocomposite showed excellent water dispersibility because of the hydrophilicity of Fe3O4 and RGO. Adsorption experiments indicated that Fe3O4@PPy/RGO adsorbs methylene blue fast and efficiently, with an adsorption capacity of up to 270.3 mg g−1. The kinetic adsorption data fit the pseudo-second-order model and the isotherm data followed the Langmuir model. Additionally, adsorption of MB on Fe3O4@PPy/RGO also can utilize the electrostatic interaction and π–π interaction between Fe3O4@PPy/RGO and MB. Moreover, compared to other nanoparticle adsorbents, the as-prepared Fe3O4@PPy/RGO is highly flexible and easy to operate and retrieve. Most importantly, it is easy to disperse, which enables its potential application in wastewater treatment.

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