Synthesis and Characterization of Magnetite for Pollutant Remediation

Phosphorus is one of the limiting nutrients for crop production, especially in developing countries where soil available P is low. To counter P deficiency, P has been applied at a rate above crop uptake which makes management of P fertilizer a challenge for the scientific community, as high input P can have environmental consequences like eutrophication of water bodies. Physico-chemical and biological methods are widely used for the removal of soluble P from wastewater. Adsorption of P onto a paramagnetic substance like magnetite holds a great promise for its removal and subsequent recovery of adsorbed P. The present study was carried out with the objective of synthesis of magnetite in different molar ratios and its characterization to select the best magnetite material for removal of P. Magnetite was synthesized using the co-precipitation method using ferrous and ferric ions at different molar ratios (1:1, 1:2, 2:1, 5:1) and characterized for Xray diffraction, Fourier transforms infrared spectroscopy, and Brunauer-Emmett-Teller method surface area. All the synthesized material resembled the Joint Committee on Powder Diffraction Standards XRD patterns of reference magnetite and showed strong peaks at 220, 311, 400, 511, and 440 cm-1. FTIR analysis showed the presence of Fe-O bond at 580 cm-1 and characteristic peaks at 1633 and 3400 cm-1 suggesting the presence of a hydroxyl group. Highest surface area (93.001 (m2/g) was observed for magnetite synthesized with a molar ratio of 1:2 (Fe2+/ Fe3+), whereas the surface area of the rest of the synthesized magnetite was close to 50 m2/g. The smallest pore radius was also found in magnetite synthesized with a molar ratio of 1:2 (Fe2+/Fe3+) which contributed to the highest pore volume.