Pb(II) ions removal via green spinel NiFe2O4 loaded on g-C3N4 nanomaterials

Abstract

A novel nickel ferrite-graphitic carbon nitride (NFCN) composite was prepared from green NiFe 2O4 nanomaterials and g-C3N4 using ultrasonic power in alcoholic medium for adsorbing Pb(II) ions from aqueous solutions. The X-ray diffraction (XRD) results showed the mutual existence of both the ferrite and nitride phases, which were confirmed by scanning electron microscope (SEM) morphological images, EDX analysis, X-ray photoelectron spectroscopy (XPS) chemical composition and Fourier transform infrared spectroscopy (FTIR) band identification. The Brunner-Emmet-Teller (BET) analysis revealed a highly porous nanostructure with surface area of 118 m2g−1 that made it a competent adsorbent to achieve a maximum adsorption capacity of 540.55 mg g−1 for Pb(II) ions from aqueous solution under the optimal conditions. Furthermore, the adsorption kinetics and adsorption isotherm analysis showed that the adsorption process followed the pseudo-second-order kinetic model and Langmuir adsorption model, specifying that the adsorption of Pb(II) ions by the NiFe2O4@g-C3N4 nanocomposite is monolayer chemisorption. The adsorption mechanism was found to be intraparticle as well as film diffusion controlled. On the other hand, the -NH2 and -OH functional groups within the nano-adsorbent structure were proved to coordinate with the Pb(II) ions, as supported by the FTIR analysis. The results demonstrate that the NiFe2O4@g-C3N4 nanocomposite has a high capacity and is reusable for Pb ion adsorption.