Environment-friendly synthesis of Ni0.5Zn0.5Fe2O4 magnetic nanoparticles using Plantago major and its applications as an efficient and rapid adsorbent for removal of reactive blue 21 dye

Abstract

ABSTRACT The Ni0.5Zn0.5Fe2O4 magnetic nanoparticles (MNPs) were synthesised using Plantago major seed extract through an environment-friendly, economic, and easy procedure. The nanoparticles were characterised by FTIR, XRD, SEM, TEM, EDX, BET surface area analysis, and VSM. The Ni0.5Zn0.5Fe2O4 MNPs were investigated as a nanoadsorbent for removal of reactive blue 21 (RB 21) and the results showed that the nanoparticles were effective for adsorption of RB 21. More than 93% of RB 21 was removed by the nanoadsorbent after a short time of 10 min (60 mg of nanoadsorbent dosage at concentration of 20 ppm for RB 21). The effect of initial concentration of RB 21 and nanoparticle dosage on dye adsorption were investigated. The Langmuir and Freundlich isotherm models used for adsorption equilibrium of RB 21 on Ni0.5Zn0.5Fe2O4 MNPs. The isotherm studies showed that the Langmuir model (KL = 2.76 L/mg, qmax = 18.08 mg/g) provides more compatible than the Freundlich model and thus RB 21 adsorb on the surface of Ni0.5Zn0.5Fe2O4 MNPs by a mono layer adsorption. The adsorption kinetics studies for the adsorption of RB 21 on Ni0.5Zn0.5Fe2O4 MNPs were conducted using the pseudo first-order, the pseudo second-order, and the intraparticle diffusion models and the results indicated that the pseudo second-order model (qe = 15.19 mg/g) provides more compatible than the other models for the adsorption of RB 21 on Ni0.5Zn0.5Fe2O4 MNPs. The maximum adsorption capacity was determined as 16.65 mg/g.