In this paper, a modified mesoporous Fe-MCM-41 based catalyst was synthesized and evaluated in removal of oxalic acid by catalytic ozonation. With the introduction of two active metal oxides (i.e. manganese and cerium oxides) at various loadings on Fe-MCM-41, the elimination of oxalic acid was increased to 83% from its initial concentration. The catalytic activity was found to strongly depend on the proportions of the active compounds. Cerium oxide was more effective active compound than manganese oxides because it led to higher degradation efficiency of oxalic acid. The iron content and the proportions of the metal oxides loadings were optimized. The application of optimum catalyst formulation (0.75 wt% manganese oxides and 1.19 wt% cerium oxide on Fe-MCM-41 with 1 wt% iron content) in the presence of ozone was found to be remarkably promising in degradation of oxalic acid. The optimum supported catalyst could practically remove 94% of the oxalic acid. It was observed that the higher adsorption of oxalic acid on the catalyst samples, the higher elimination of oxalic acid by catalytic ozonation. Therefore, it was deduced that the adsorption of oxalic acid influenced the catalytic activity of the supported catalysts. It is believed that the oxidation of adsorbed organic pollutant on the surface predominantly occurred during the catalytic ozonation processes. (C) 2016 Elsevier B.V. All rights reserved.