The effect of iron nanoparticles on chemical distribution of lead in a calcareous soil

There are few reports about application of iron nano particles in remediation of contaminated soil. Thus, this study was conducted and focused on evaluation of iron nano particles efficiency for fixation of Pb2+ in soil. This experiment was carried out in the factorial experiment with completely randomized design with two types of iron nano particles including zero-valent iron and iron oxide (Fe2O3) with two times (3, 21 day) in three replications. Results from a sequential extraction showed that zero-valent iron nano particles (nZVI) significantly decreased water soluble/exchangeable Pb2+ and carbonate form from 3.6% and 40.0% in the untreated soil to 2.8% and 34.3% and concomitantly increased Pb2+ residual and organic matter form from 8.3% and 1.6% to 13.6% and 2.2%, respectively. In the presence of iron oxide nanoparticles, Pb2+ residual form significantly increased, whereas Pb2+ bounded with Mn/Fe oxide decreased from 48.7% to 44.5%. The extraction with EDTA was used to quantify the Pb availability in soil. Results showed that EDTA extractable Pb2+ significantly decreased in soil treated with nZVI, whereas, there is no significant difference between the nano iron oxide and untreated soil treatments. Moreover, in untreated soil Pb2+-EDTA increased significantly with time, while in case of other treatments it was not significant. Generally, it seems that the application of iron nanoparticle had not effective role in stabilization of lead in studied soil.