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. Industrial activities have released large amounts of metals (Cu, Cd, Pb, Zn, etc.) and metalloids (especially As) into the environment and caused serious damage to the ecosystem 1. In addition, metals and metalloids can endanger human health, as many of them are toxic even at very low concentrations, and even carcinogenic (e.g. As) and mutagenic 2. Unlike organic pollutants that can degrade into harmless small molecules, the abovementioned inorganic pollutants are recalcitrant to many biochemical reactions and thus particularly difficult to remove from soils 3. Regarding As, several studies have confirmed that between 52,000 and 112,000 tons of this metalloid are released into the environment every year 1,4,5. Many diseases, such as lung cancer, skin cancer, bladder cancer, etc., can be caused by contact with As 6,7. Given that As is highly toxic for humans, and also for plants and animals, it has been classified as a priority hazardous pollutant. Unlike the aforementioned metals, As is an anionic contaminant. In this regard, simultaneous remediation of soils affected by anionic and cationic contaminants is a challenge 8 ; i.e., As remediation is even more complex in contexts of concurrent pollution with metals. In fact, classical remediation approaches attempt, among other objectives, to raise the pH of soils contaminated with cationic metals and thus stabilize them. However, this approach causes As to be solubilized 9. Overall, the various remediation strategies available focus on the disjuncture between immobilization and mobilization of the pollutants 10. Soil nanoremediation by means of Fe-nanoparticles (nZVI) simultaneously reduces the availability of As and metals in polluted soils, as shown in recent pilot-scale in situ trials 11 , and by means of hybrid soil-washing techniques 12. nZVI have a Fe° core surrounded by an oxide/hydroxide shell, which grows thicker as iron oxidation progresses. In addition, nZVI pres...
