Fabrication of super paramagnetic nanoparticles by sol-gel method for water purification

摘要

Present work is focused on synthesis and characterization of super paramagnetic nanoparticles which showed a high adsorption capacity of dyes which are the first contaminant to be recognized in wastewater of different industries such as paper and textiles. One of these dyes is congo red which is an anionic diazo dye with two azo groups. Magnetite (Fe_3O_4) nanoparticles were prepared successfully by Sol-Gel method by using ferric nitrate (Fe (NO_3)_3 9H_2O) and ethylene glycol (C_2H_6O_2) as precursors which were annealed at different temperatures. The obtained nanoparticles were characterized by X-Ray Diffraction (XRD), Transmission Electron Microscopy (TEM), Vibrating Sample Magnetometer (VSM) and Zeta Potential. The phase structures, particle sizes and morphologies of Fe_3O_4 nanoparticles were determined by XRD and TEM. VSM shows the magnetic properties of nanoparticles. The results indicate that the obtained nanoparticles are single phase and the particle size and coercivity value of Fe_3O_4 nanoparticles increased with the increase in annealing temperatures. Zeta Potential determined the surface charge of nanoparticles and the results show that nanoparticles can adsorb congo red. The adsorption capacity was evaluated using both the Langmuir and Freundlich adsorption isotherm models.