Theoretical study of nitrate elimination in drinking water using metal oxide catalysts

Abstract

The use of catalytic technologies to purify water contaminated with high levels of nitrates is of great interest in our country, where the contamination of fresh water with these ions is no longer an isolated or infrequent event. This occurs due to the confluence of various factors, for example, the increased use of fertilizers, pesticides, and contamination with chemical waste from domestic and industrial origin. Catalysts based on metal oxides have been shown to be highly efficient of removing these ions from water. In this work, theoretical modeling was carried out, based on Density Functional Theory (DFT), of the sodium nitrate (NaNO₃) adsorption on different metal oxides, in the presence and absence of water. It could be observed that the most favorable substrate for nitrate adsorption is TiO₂ anatase, in both situations. In the 2H₂O-NaNO₃/MgO system, the dissociation of a water molecule can be observed.