Degradation of oxalic acid from aqueous solutions by ozonation in presence of Ni/Al2O3 catalysts

The ozonation of oxalic acid has been carried out in an agitated slurry semi-batch reactor using NiO/Al2O3 as catalysts. The presence of catalysts in the ozonation processes significantly improves the oxalic acid removal rate, in comparison to the catalytic process. The influence of calcination temperature on the catalyst activity and on leaching of the active component was assessed. At the experimental conditions applied, the catalytic process develops under complete mineralization of organic substrate. The proposed mechanism justifies the first order kinetic experimental for oxalic acid and ozone. This kinetics also complies with experimental results obtained for different temperatures, ozone partial pressure and different mass of catalyst per slurry volume.