Synthesis of a novel biocomposite from orange peels and its application for the removal of diclofenac from aqueous solutions: assessment of adsorption characteristics

This work aims to synthesize and to characterize an easily recoverable magnetic composite (orange peel composite [OPC]) from orange peel (OP) and to apply it as an effective adsorbent for the removal of an industrial drug (diclofenac (DFC)) from aqueous solutions in batch mode. The OP and OPC characterization through various techniques including Fourier transform infrared, scanning electron microscopy coupled with energy-dispersive spectroscopy, X-ray diffraction, Brunauer–Emmett–Teller, and thermogravimetric analysis shows that the OPC has interesting physicochemical properties in comparison with numerous other adsorbents. The DFC removal by the OPC is found to be time-dependent, and the equilibrium state is obtained after 90 min. Moreover, at a temperature of 30 °C, the DFC adsorption capacity by this magnetic material is estimated to be 37.0 mg·g –1 , which is higher than various adsorbents. In addition, the thermodynamic study results indicate that DFC removal is a feasible, exothermic, and spontaneous process. All these results prove that magnetized OP wastes can be considered a promising material for the efficient removal of DFC from aqueous solutions under a wide range of experimental conditions.