Fast Removal of Methylene Blue from Aqueous Solution Using Magnetic-Modified Fe3O4 Nanoparticles

Tannic acid modified super paramagnetic Fe3O4 nanoparticles (Fe3O4-TAN) were synthesized by a simple strategy and were used as adsorbents for removal of methylene blue (MB) from water solution. The prepared magnetic nanoparticles (MNPs) were characterized by Fourier transform infrared (FT-IR), transmission electron microscopy (TEM), thermogravimetric (TGA), and X-ray diffraction (XRD) analyses. The effects of pH, contact time, dye concentration, and temperature on adsorption were determined. The experimental data were analyzed using the Langmuir adsorption model. The data fitted well to the model with maximum adsorption capacities 90.9 mg/g under pH = 10.5. Also, the adsorption kinetics and thermodynamic parameters were studied and evaluated. Adsorption of the MB to nanoparticles reached equilibrium after 25 min. In addition, the external magnetic field could easily separate nanoparticles from water with high separation efficiency. Desorption process of the adsorbed dyes was also investigated. 2014 American Society of Civil Engineers.