Efficient removal of Malachite Green from aqueous solution by adsorption on carbon nanotubes modified with ZnFe2O4 nanoparticles

Abstract

In this study, multiwall carbon nanotubes modified with spinel zinc ferrite nanoparticle (ZnFe2O4/MWCNTs) were used as a solid phase adsorbent for the removal of Malachite Green (MG) from aqueous media. The synthesized nanocomposite was characterized by different methods, such as Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM) and X-ray diffraction (XRD). Batch adsorption experiments to determine the optimal adsorption conditions and different factors that influence the adsorption efficiency (i.e., pH, amount of adsorbent, contact time, and the initial concentration of MG) were also evaluated and optimized. The data were satisfactorily fitted to the Langmuir model and a maximum adsorption capacity of 116.2 mg g-1 was obtained at a pH of 7.5. In addition, adsorption kinetics studies were performed. The adsorption of the model dye (MG) was found to reach equilibrium after 60 min, following a pseudo-second-order kinetic model. Furthermore, an external magnetic field could easily separate the nanoparticles from water with a high separation efficiency.