| Ozone is a powerful oxidising agent able to achieve the degradation of the phenolic compounds found in olive oil mill wastewaters. Carboxylic acids and aldehydes are obtained as major degradation products.; A mechanism has been proposed to explain the degradation of the cinnamic acid derivatives. The rate of the degradative reaction depends on the pH and the substitution of the aromatic ring. UV radiation and the combination UV-ozone do not improve the oxidative process.; 2,4,6-triphenylpyrylium cation is able to catalyse the photodegradation of the phenolic compounds, using atmospheric oxygen as the real oxidising agent and solar light as a source of energy. This photocatalyst acts via an electron-transfer mechanism. The pyrylium salt-catalysed solar photodegradation of the phenolic pollutants follows a first order kinetics, and the value of the rate constant depends on the substitution of the aromatic ring.; The existence of an electron-transfer mechanism between the pyrylium cation and the substrate is shown by the linear relationship observed between the decrease of the fluorescence emission of the pyrylium cation and the concentration of the substrate (Stern-Volmer relationship). The rate constant for the electron-transfer process calculated from the Stern-Volmer plot is in good correlation with the degradation yields obtained in the solar reactions.; The ozonisation process produces a strong increase in the biodegradability in the samples that have been studied, while in the case of the pyrylium salt this effect is not found. This fact can be explained by the different mechanism followed in both cases. |
