Evaluation of Kinetic and Equilibrium Parameters of NiFe2O4 Nanoparticles on Adsorption of Reactive Orange Dye from Water

Background: Among different pollutants released into the environment, dyes are considered as one of the most dangerous contaminants. In recent years, magnetic nanomaterials have attracted much attention for their dye removal capacity. The aim of this study was to explore the adsorption kinetics of an anionic dye (Reactive Orange 13 (RO)) by NiFe2O4 nanoparticles (NiFe2O4 NPs) under various conditions. Methods: NiFe2O4 nanoparticles (NiFe2O4 NPs) were prepared and characterized by X-ray diffraction (XRD), transmission electronic microscopy (TEM), pHpzc and BET methods. The adsorption characteristics of the NiFe2O4 NPs adsorbent were examined using Reactive Orange 13 as an adsorbate. The influences of parameters including pH, dose of adsorbent and contact time were investigated to find the optimum adsorption conditions. Results: Decreasing solution pH and increasing contact time were favorable for improving adsorption efficiency. The kinetic and isotherm data of RO adsorption on NiFe2O4 NPs were well fitted by pseudo-second-order and Langmuir models, respectively. Conclusion: The maximal adsorption capacity of RO was 243.9 mg g-1 at 25◦C and pH 3.0 and the adsorption of RO on the NiFe2O4 NPs follows a monolayer coverage model. NiFe2O4 NPs might be an effective and potential adsorbent for removing anionic dyes from aqueous solutions.