Synthesis of nickel ferrite/titanium oxide magnetic nanocomposite and its use to remove hexavalent chromium from aqueous solutions

Abstract

Chromium, due to its accumulative property in the human body tissues besides carcinogenesis and toxicity, is one of the most harmful contaminants of aqueous and environmental resources. The aim of this research was to synthesize nickel ferrite/titanium oxide magnetic nanocomposite (FeNi3/TiO2 nanocomposite) and assess its potential of removing hexavalent chromium ion from aqueous solutions. FeNi3/TiO2 nanocomposite was characterized by different techniques including Transmission Electron Microscope (TEM), Vibrating Sample Magnetometer (VSM), Fourier Transform Infrared Spectroscopy (FT–IR) and X-ray Diffraction (XRD). The results showed that the FeNi3/TiO2 nanocomposite was synthesized with average size of 25nm. Chromium (VI) ion removal from the aqueous solution was determined via Flame Atomic Absorption Spectrometer (CountrAA700). The influences of pH, contact time, adsorbent dosage, and the initial chromium concentration were investigated on the chromium adsorption process using Langmuir, Freundlich and Temkin adsorption models, besides Pseudo Second-order kinetic isothermal models. The results showed that magnetic nanocomposite can remove 82.67% of hexavalent chromium with an initial concentration of 0.5mg/l under optimum conditions (pH=3, time=15min, dose of absorbent, 500mg/l). The correlation coefficients in the Langmuir, Freundlich and Temkin models were equivalent to 0.979, 0.995 and 0.8344, respectively, but according to the chromium adsorption process data it better follows the Freundlich model. The chromium removal kinetics by the synthesized FeNi3/TiO2 nanocomposite followed well the Pseudo Second-order kinetic model. The results showed that FeNi3/TiO2 nanocomposite can be used as an effective material for the removal of chromium hexavalent from the aqueous solutions.