Efecto de las nanopartículas de magnetita en el comportamiento de metales pesados en suelos contaminados

Résumé

In recent years it has been proposed the application of nanoparticles of iron and other metallic oxides as sorbents for the retention of heavy metals in soil and water. Among these, magnetite nanoparticles can be easily separated from soil by an external magnetic field, allowing for the recovery of their associated metals. This work aims to study the effect of the application of magnetite nanoparticles and their magnetic separation on the reduction of metals (Cu, Pb, Zn) and As content in contaminated soils. Samples collected from three mine soils were incubat- ed with magnetite nanoparticles at different application rates (0, 25 and 50 g kg-1) and with different moisture (dry and at field capacity). The effect of contact time between soil and magnetite was also evaluated along 15, 30 and 45 days. Different fractions were separated using an electromagnet and total content of metals was determined in them by ICP-OES. The magnetite managed to separate with the magnetic field an important amount of soil and to considerably reduce metals concentration, especially at the highest application rate and at field capacity. Contact time did not produce significant effects. The use of magnetite nanoparticles and their magnetic separation can be a useful tool for the reduction of metal contamination levels in soils.