Preparation of Pyramids Structured Silicon as a Support for Nano Sized Zero Valent Iron Particles for Nitrate Removal from Water

Abstract

In this study, pyramids structured silicon (PSi) has been made from metallurgical grade silicon powder with wet alkaline etching and then chemically activated with nano zero valent iron (NZVI) to eliminate nitrate. The NZVI/PSi composite was characterized by scanning electronic microscopy (SEM), X-ray diffraction(XRD), X-ray fluorescence spectrometer (XRF), energy dispersive X-ray spectroscopy (EDS), Fourier transform infrared spectroscopy (FTIR), and UV–Vis spectrophotometry. The size of NZVI particles was between 30–100 nm coated on PSi without clustering of the NZVI particles due to the electromagnetic attraction forces. The synergistic effect of NZVI/PSi composites obviously increased remarkably nitrate removal efficiency than NZVI alone. Chemical reduction of nitrate by zerovalent iron in water requires acidic pH conditions but NZVI/PSi composite can reduce nitrate in water in the pH range of 2–7. Also, removal of nitrate complete in 20 min by NZVI/PSi composite that was shorter than NZVI in 120 min. Above all, this composite completely was separated from solution with external magnetic field.