Ethanol concentration as organic matter delayed the NAP elimination and O₃–NiO increased the mineralization degree and oxidation state of byproducts.

This study evaluates naproxen (NP) degradation efficiency by ozonation using nickel oxide films ($Ni{O}_{\left(F\right)}$) as a catalyst. The NiO films were synthesized by chemical vapor deposition and characterized by X-ray diffraction, scanning electron microscopy, atomic force microscopy and X-ray photoelectron spectroscopy. NP degradation was conducted for 5 min using 10 films of $Ni{O}_{\left(F\right)}$ comparing against ozonation using 100 mg/L $NiO$ powder in suspension ($Ni{O}_{\left(S\right)}$) and conventional ozonation ($O_3$-conv). Total organic carbon analysis demonstrated a mineralization degree of 12% with $O_3$-conv, 35% with $NiO$ as powder and 22% with $Ni{O}_{\left(F\right)}$ after 60 min of reaction. The films of $Ni{O}_{\left(F\right)}$ were sequentially used 4 times in ozonation demonstrating the stability of the synthesized material, as well as its properties as a catalyst for ozonation. A proposed modeling strategy using robust parametric identification techniques allows the comparison of NP decomposition pseudo-monomolecular reaction rates.

Freshwater pollution compromises drinking water in a worldwide context. Water pollution is one of the major environmental challenges facing humanity. Therefore, the application of methods to control the pollution in water is a growing research field. Among the methods, ozone has been widely applied due to its high oxidation potential. However, one disadvantage is the presence of refractory organic compounds that are partially oxidized leaving mineralization incomplete. Several approaches have been considered to improve the oxidizing power, reducing the reaction time, and increasing the mineralization degree of ozone. So far, the combination of a solid catalyst with ozone (catalytic ozonation) has shown to enhance the degradation of refractory organic compounds in water. This chapter presents the combination of different metallic oxides (Al2O3, TiO2, SiO2, and NiO) with ozone to determine the effect of ozone decomposition and the subsequent elimination of one chlorinated compound (2,4-D). The chemical structure of the initial compound (2,4-D, benzoic and phthalic acid), as well as the initial catalyst dosage (0.1 and 0.5 g L−1) with the mentioned compounds, was also studied. Moreover, the degradation of two aromatic compounds (naphthalene and naproxen) with different proportions of ethanol (representing the organic matter of wastewater) was analyzed to establish their effect on the catalytic ozonation process.