BACKGROUND: The formation of carboxylic acid, especially oxalic acid (OA), limits the complete mineralization of organic pollutant in both ozonation and catalytic ozonation. Bimetallic catalyst is well known for its catalytic activity. In this study, bimetallic Fe-Cu-MCM-41 is synthesized to accelerate ozone decomposition to center dot OH and enhance OA degradation. RESULTS: After the employment of Fe-Cu-MCM-41/O-3, 95% OA was removed at 60 min, which was much higher than that in Fe-MCM-41/O-3 (23.4%), Cu-MCM-41/O-3 (69.7%) and a single ozonation process (16.5%). Using pyridine adsorption-IR, ESR and XPS, a relationship was found between catalytic activity of catalysts, Lewis acid sites and electron transfer effect. OA degradations were found to follow a hydroxyl radical mechanism. The Fe-Cu-MCM-41/O-3 process was sensitive to pH value; a higher removal efficiency was achieved under alkaline conditions. Fe-Cu-MCM-41 significantly accelerated ozone decomposition, hydroxyl radicals and hydrogen peroxide generation. CONCLUSIONS: Co-incorporating Fe and Cu successfully increased the number of Lewis acid sites on MCM-41. Electron transfers between Fe(II/III), Cu(I/II) and O-3 were also found. The joint function of Lewis sites and the electron transfer effect enhanced center dot OH generation and OA degradation. Fe-Cu-MCM-41 showed bright prospects for use in water treatment processes. (C) 2017 Society of Chemical Industry