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 (Fe 3 O 4 /FeS 2 ) 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 Fe 3 O 4 /FeS 2 composites. The comparative experiments among FeS 2 , Fe 3 O 4 and Fe 3 O 4 /FeS 2 for the removal of Cr(VI) and phosphate were carried out. The Fe 3 O 4 /FeS 2 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 Fe 3 O 4 , Fe 3 O 4 /FeS 2 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 FePO 4 precipitates. The efficient removal of Cr(VI) and phosphate and the great performance of solid-liquid separation show that Fe 3 O 4 /FeS 2 nanocomposite is a promising material for Cr(VI) and phosphate contaminated wastewater treatment.