Simultaneous removal of chromium(VI) and phosphate from water using easily separable magnetite/pyrite nanocomposite

The treatment of multi-component pollutants in wastewater is a challenge. In this work, a novel nanoscale magnetite/pyrite (Fe3O4/FeS2) composite was successfully synthesized, characterized and applied in simultaneous removal of Cr(VI) and phosphate. Transmission electron microscopy, X-ray photoelectron spectroscopy, Vibrating sample magnetometer, Fourier transformed infrared spectroscopy, and X-ray diffraction analysis were applied in characterization of Fe3O4/FeS2 composites. The comparative experiments among FeS2, Fe3O4 and Fe3O4/FeS2 for the removal of Cr(VI) and phosphate were carried out. The Fe3O4/FeS2 composite with molar ratio of 1:4 exhibited remarkable performance on the removal of Cr(VI) and phosphate at initial pH 3.0. Compared with bare Fe3O4, Fe3O4/FeS2 exhibited an enhanced removal of Cr(VI). Cr(VI) removal includes electrostatic attraction and reduction. The removal of phosphate was due to electrostatic attraction and the formation of FePO4 precipitates. The efficient removal of Cr(VI) and phosphate and the great performance of solid-liquid separation show that Fe3O4/FeS2 nanocomposite is a promising material for Cr(VI) and phosphate contaminated wastewater treatment. (C) 2019 Elsevier B.V. All rights reserved.