NiFe₂O₄/activated carbon magnetic composite as potential adsorbent material for the removal of pharmaceuticals from aqueous media

Full text: NiFe_2O4/activated carbon magnetic composite was produced by hydrothermal method, characterized and preliminary tested to adsorb the emerging contaminants ibuprofen and ketoprofen from aqueous media. The magnetic composite produced as well as the activated carbon and the magnetic particles were characterized by Fourier transform infrared spectroscopy (FT-IR), energy dispersion spectroscopy (EDS), X-ray diffraction (XRD), vibrating sample magnetometer (VSM), N₂ adsorption isotherms (BET) and scanning electron microscopy (SEM). The adsorption study evaluated the the pH effect and adsorbent dosage. The characterization results demonstrated that the magnetic composite presented functional groups of activated carbon coupled with intrinsic characteristics of the metal at tetrahedral site. Furthermore, the material was mainly composed of its particle atoms and presented crystalline and amorphous structure. Besides that, the magnetic composite produced presented sufficient magnetic character to be separated from the solution by an external magnetic field and also presented high value of surface area. Lastly, SEM images showed cavities and protuberances, typical of activated carbon and an agglomeration of small magnetic particles due to NiFe₂O₄ presence. The adsorption was favored at adsorbent dosage of 0.5 g L^-1 and at pH 2, presenting high values of adsorption capacities and removal percentages close to 100%. Thus, it can be concluded that the magnetic composite produced has a great potential to be used as adsorbent to remove pharmaceuticals from aqueous media, presenting the advantage of an easier separation process due to the magnetic particles presence. (author)