Nanoremediation of As and metals polluted soils by means of graphene oxide nanoparticles

The capacity of graphene oxide nanoparticles (nGOx) to reduce or increase As and metals availability in polluted soils was compared with that of zero valent iron nanoparticles (nZVI). The nanomaterials used in this study were characterized by X-ray techniques, CHNS-O analysis, dynamic light scattering, and microscopy procedures such as atomic force microscopy. To assess the capacity of these materials to immobilize pollutants, field samples of two soils were treated with nZVI and nGOx at a range of doses (0.2%, 1% and 5%). Availability tests were then performed. nGOx effectively immobilized Cu, Pb and Cd, but mobilized As and P (even at low doses), in the latter case irrespective of the simultaneous presence of high concentrations of metals. In turn, nZVI promoted notable immobilization results for As and Pb, a poorer result for Cd, and an increased availability for Cu. Soil pH and EC have been slightly affected by nGOx. On the whole, nGOx emerges as a promising option for mobilization/immobilization strategies for soil nanoremediation when combined with other techniques such as phytoremediation.