Catalytic ozonation of phenolic compounds: The case of gallic acid

The catalytic ozonation of gallic acid has been carried out in the presence of a perovskite type material (LaTi_0.15Cu_0.85O₃). Some of the main operating parameters like temperature, catalyst and ozone doses exerted a positive influence in the ozonation rate. Contrarily, initial gallic acid concentration showed a negative effect in terms of conversion while the optimum working pH was found to be around 2 (3.5 if deactivation is avoided). Addition of tert-butyl alcohol (free radical scavenger) had no effect on the catalytic removal of gallic acid, although its presence decreased the mineralization degree achieved. The catalyst demonstrated a high stability in terms of the acid removal, however, a partial deactivation was experienced in terms of organic carbon elimination if compared the first and second reuses. The catalyst kept its activity after further reutilisations. Due to the moderate regime developed in the homogeneous phase, the process was better simulated by an empirical expression rather than using a detailed model.