Graphene oxide-based ZnFe₂O₄ catalyst for efficient adsorption and degradation of methylene blue from water

Abstract

This study describes a novel eco-friendly method for the synthesis of rGo/ZnFe₂O₄. The synthesized material has been applied as an adsorbent and photo-catalyst for the removal of methylene blue from aqueous solution. Graphene oxide was used as precursor, and FeCl₃·6H₂O and ZnSO₄ have been anchored onto its framework through in situ reaction using ethanol as green solvent at 40 °C. The synthesis of rGo/ZnFe₂O₄ has been confirmed using x-ray diffraction and Fourier transform infrared spectroscopy. Scanning electron microscopy (SEM) and tunneling electron microscopy (TEM) study revealed excellent surface morphology of the composite. Similarly, insertion of Fe ions imparted magnetic character and made the rGo/ZnFe₂O₄ as recyclable sorbent/degradation agent. Evaluating the process at different pH value indicates that at pH 4 and 10, both adsorption and degradation take place, respectively, while at neutral pH, that is, 7, only adsorption is predominant process. The composite exhibits excellent degradation of 82% and 90% at pH 4 and 10, respectively, while at neutral pH, it shows 85% adsorption only. The composite has excellent regeneration ability and remains efficient in degradation of methylene blue for six cycles.

Graphical Abstract

Keywords:

• Graphene oxide
• ZnFe₂O₄
• methylene blue