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

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 Fe0 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 Fe0 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.