Reduction of nitrate by copper-coated ZVI nanoparticles

Nano zero-valent iron has been shown to be effective for the removal of nitrates from natural wastes and wastewaters. This work studies the application of surface-modified nano zero-valent iron as bimetallic Fe/Cu particles to remove high concentration of nitrates. Dispersed nano-Fe/Cu particles were synthesized by chemical reduction and examined by X-ray diffraction, scanning electron microscopy, and BET surface area analysis. Batch experiments were conducted to investigate the effectiveness of bimetallic particles on the reduction and removal of nitrates. The parameters investigated included the copper content (0.5, 5, 10, and 20% w/w) in zero-valent iron nanoparticles and the initial concentration of nitrates (100, 200, 300, and 500 mg/L). During the experiments, the aqueous solution was analyzed to determine the evolution of NO33- as well as NO2-, NH3, and NH4+ which were produced as intermediate and final products. Based on the results obtained, it was concluded that the optimum coating rate was 5% w/w copper in nano-Fe/Cu, resulting in more than 80% nitrate reduction in 20 min and complete removal within 1 h.