Effect of Hydrogen Nutrition Denitrifying Bacteria on Nanoscale Zero-Valent Iron Settlement

Abstract

Nanoscale zero-valent iron (nZVI) particles has an extremely small size and can be suspended in groundwater for long periods of time to remove contaminants. However, more and more experimental results show that the migration performance of nZVI particles in groundwater is far lower than expected, and it is difficult to meet the actual needs of in-situ remediation. In order to study the effect of hydrogenotrophic denitrifying bacteria on Nano-iron, the sedimentation test was used as the main research method to discuss the demonstration. The experimental results showed that within the pure water system and in the culture solution system, the sedimentation rate of Nano-iron was decreased after adding bacteria. As the amount of bacteria in the system increases, the sedimentation rate of Nano-iron tends to decrease. When the amount of bacteria reaches a certain amount, it will have a saturating effect on the sedimentation effect of Nano-iron. XRD spectra showed that Fe3O4 and Fe2O3 were the main iron oxides in the initial oxidation, while Fe2O3, Fe3O4 and Fe2O3 were obtained in the final time of sedimentation. Amorphous 5-FeOOH (corrosion product of zero-valent iron in pure water) replaces Fe2O3 and Fe3O4 as major corrosion products after the addition of bacterial reaction.