Nitrate reduction by nano-Fe/Cu particles in packed column

In this work the application of a modified surface nano zero valent iron (NZVI) as bimetallic Fe/Cu particles to remove high concentration of NO3--N through packed sand column has been studied. Dispersed nano-Fe/Cu particles has been synthesized in water mixed ethanol solvent system (1:4 v/v) and described by XRD pattern, TEM and SEM images and BET analyze. Batch experiments have been conducted to investigate the effect of percentage coating of Fe-0 by Cu on the nitrate removal. Research on packed sand column (120 cm length, 6.5 cm inner diameter) has been done under conditions of Nano-Fe/Cu concentration (2, 5, and 8 g l(-1) of solution), high initial NO3--N concentration (100,200, and 300 mg l(-1)) and pore water velocity through sand (0.125, 0.250, and 0.375 mm s(-1)) in seven sets. Results of batch experiments indicated the efficient coating percentage of Fe-0 by Cu in NO3--N reduction was 2.5% (w/w). In addition, increase of pore velocity of water through packed sand has negative effect on the nitrate reduction rate. In contrast, increasing the injected mass of nano particles and the influent NO3--N concentration would increase the rate of NO3--N reduction. The best condition to reduce NO3--N has been observed at end of sand column as 75% of influent concentration when nano-Fe/Cu concentration = 8 g l(-1), high initial NO3--N concentration = 100 mg l(-1) and pore water velocity through sand = 0.125 mm s(-1). (C) 2011 Elsevier B.V. All rights reserved.