Fabrication of Magnetic NiFe₂O₄ Nanorods and Their Removal Performances of Congo Red

Abstract

Magnetic NiFe2O4 nanorods were prepared successfully via a facile solution combustion process, the morphology, chemical composition, microstructure and magnetic properties of as-prepared NiFe2O4 nanorods were investigated by XRD, VSM, SEM, TEM, EDX, SAED and BET techniques. The magnetic NiFe2O4 nanorods were characterized with average length of about 130 nm, the diameter of around 25 nm, the specific magnetization of 105.2 Am2/kg, and the specific surface area of 88.8 m2/g. The nanorods were employed to remove congo red (CR) from aqueous solutions, the adsorption kinetic and adsorption isotherm of CR onto NiFe2O4 nanorods at room temperature were investigated. The regression equation was found in good agreement with the pseudo-second-order kinetic model in a range of initial CR concentrations of 80-400 mg/L. Compared with Freundlich and Temkin models, Langmuir model fitted the adsorption isotherm of CR onto NiFe2O4 nanorods better, which suggested that the adsorption of CR onto NiFe2O4 nanorods was a monolayer absorbing mechanism. Meanwhile, the adsorption capacity of CR onto NiFe2O4 nanorods is large when pH is less than 9.