Study on the reductive transformation of nitrite by nanoscale zero-valent iron particles synergized with ultrasonic technology

This research was focused on the removal of nitrite by nanoscale zero-valent iron (NZVI). NZVI particles were prepared by liquid phase reduction method using NaBH4 as reducing agent, and were employed for the denitrification of nitrite in simulated water samples. Ultrasonic technology was used to enhance the denitrification efficiency. Kinetic studies revealed that the denitrification process was a pseudo first-order reaction with respect to nitrite concentration under the given experimental conditions. The factors affecting the denitrification efficiency such as ultrasonic time, NZVI dosage, initial nitrite concentration and solution pH have been investigated. The reaction rate constant (k(obs)) was found to be increased with the increase of NZVI dosage, but the reverse action was observed for pH effect.