Adsorption studies of amine-modified green synthesized Fe_3O_4 nanoparticles for the removal of nickel from aqueous solution

摘要

The magnetite nanoparticles were synthesized through co-precipitation method and were coated with neem (Azadirachta indica) leaf extract. The adsorbent was further modified by the addition of ethylene diamine for better performance. The synthesized material was characterized by Fourier transform infrared spectroscopy, scanning electron microscopy, Energy dispersive X-ray spectroscopy, thermo gravimetric analysis and X-ray diffraction techniques. Parameters influencing the adsorption such as concentration, temperature, pH, contact time and dosage were optimized through batch studies. Isotherm studies were conducted by plotting and analyzing the Langmuir, Freundlich and Dubinin-Radushkevich isotherm models. The pseudo-first and pseudo-second order kinetic studies were carried out to understand the reaction kinetics. The adsorption was found to be efficient at room temperature with a pH of 6. The optimum dosage of adsorbent was found to be 0.2 g and the reaction attained equilibrium in 90 min. The maximum adsorption capacity of the material was found to be 19.23 mg/g from the Langmuir isotherm model. The temperature studies exhibit the reaction to be exothermic in nature. An appreciable desorption of the metal ions was obtained using 0.8 N HCl and the efficiency was found to be 79%.