The effect of zero valent iron nanoparticles on reduction of heavy metal contamination in calcareous, acidic and sandy soils

Contamination of soils with heavy metals is one of the great environmental concerns for the human beings. The application of zero valent irons nanoparticles (ZVINs) as an amendment for environmental pollutions has been highly considered by researchers in last decade. This study was conducted to synthesis and characterize the ZVINs stabilized with carboxyl methyl cellulose (CMC-ZVINs) in aerobic conditions and to assess their ability for reduction of DTPA extractable lead (Pb), cadmium (Cd), nickel (Ni) and copper (Cu) from three polluted soils including sandy-calcareous, acidic and clay-calcareous soils. An experiment of randomized completely design with a factorial arrangement of treatments consisting nano zero valent iron dosages (0, 0.5, 1 and 2 w/w %), soils (sandy-calcareous, acidic and clay-calcareous soils) at two time (10 and 20 days) with three replication were studied. The results of the SEM and XRD analyses indicated that the CMC-ZVINs had the mean size of less than 50 nm and the maximum 2θ peak at 44.8° confirming the nano sized and zero valent status of particles, respectively. Results also indicated that the DTPA extractable Pb, Cd, Ni and Cu in three polluted soils decreased with increasing of zero valent iron nanoparticles dosages. The percentage of available Pb reduction was higher in comparison with other heavy metals. The aging of nanoparticles from 10 to 20 days led to more significant reduction of DTPA extractable heavy metals. Overalls, the synthesized CMC-ZVINs can potentially be introduced as a good remediation approach for Pb, Cd, Ni and Cu contaminated soils.