Green synthesis of nano zero-valent iron/Cu by green tea to remove hexavalent chromium from groundwater

Nanoscale zero valent iron/Cu was prepared by green synthesis method and was used to remediate Cr(VI) contaminated groundwater. Nanoscale zero valent iron/Cu was characterized by scanning electron microscope, Fourier transform infrared spectroscopy, Transmission electron microscope and X-ray diffraction. Batch experiments were performed to investigate optimum condition for removal of hexavalent chromium(Cr(VI)) from groundwater by nanoscale zero valent iron/Cu. With the decrease of pH value, the decrease of the initial concentration of Cr(VI) and the increase of temperature, the removal efficiency of Cr(VI) increases. The presence of humic acids in groundwater can inhibited the activity of nanoscale zero valent iron/Cu. The removal efficiency of Cr(VI) reached 94.7% under the condition of pH of 5 and temperature of 303 K. The removal of Cr(VI) by nanoscale zero valent iron/Cu was well fitted with Langmuir-Hinshelwood first reaction kinetic model, with apparent rate constant K-obs values estimated at 0,07430, 0.09650, 0.1183 and 0.1473 min(-1) at 298, 303, 308 and 313 K. Overall, nanoscale zero valent iron/Cu is a promising green material to remove Cr(VI) from polluted groundwater. (C) 2017 Elsevier Ltd. All rights reserved.