Promotion effect of Fe2+ and Fe3O4 on nitrate reduction using zero-valent iron Original Research Article

The reductive efficiency of nitrate by zero-valent iron (Fe0) was increased under initial neutral conditions through addition of certain amount of Fe2+. Throughout the process, the NO3− and Fe2+ concentrations displayed a declining trend, but the general process was divided into three stages. It showed that Fe2+ could accelerate the corrosion of iron surface, accompanied by generating Fe3O4, and ionizing H+ which played an important role in buffering pH of the system. Fe3O4 behaved as a good conductor which favored the electron transfer on iron surface and accelerated the reductive denitrification rate of nitrate with Fe0 and Fe2+.