Individual and mixed oxides of copper and manganese are effective catalysts for various oxidation-reduction reactions, e.g., oxidation of carbon monoxide, decomposition of ozone, oxidation of organic compounds, etc. In this case, phase composition and porous structure parameters are largely determining their catalytic properties in each specific chemical process. The present work is devoted to study the influence of phase composition and adsorption-structural properties of individual and mixed copper - and manganese-containing catalysts deposited on dolomite substrate on the catalytic activity in the oxidation of Fe (II) by atmospheric oxygen in the aquatic environment. The actuality of development a highly active catalyst for this process is due to their wide practical application for the purification of groundwater from iron compounds for drinking purposes. Applied catalysts were obtained by impregnation of previously heat-treated at 800 °C natural dolomite fraction 0,63-1,0 mm aqueous solutions of chlorides of manganese (II) and/or copper (II), followed by drying at 80 °C and heat treated in the temperature range 200-600 °C. The ratio of Cu:Mn in the impregnating solution of the oxide precursor was 1:1 and 1:2, which according to literature data allows to obtain the most active mixed phase oxides of copper and manganese with a spinel structure. Samples of catalysts were characterized using low-temperature sorption-desorption of nitrogen (ASAP 2020, Micromeritics, USA) and X-ray diffraction (diffractometer D8 Advance, Germany). Evaluation of the catalytic activity of the synthesized samples was carry out by the degree of oxidation of Fe(II) to Fe(III) in a model solution for the installation of a flow-type reactor volume of 300 cm3, a linear speed of 20 m/h, initial concentration of Fe(II) 50 mg/l, pH of 6.0-6.5. The concentration of dissolved oxygen in the model solution was at the level 8.0 to 9.0 mg/L. The results demonstrate that the highest catalytic activity is offered by the catalysts prepared through impregnation with solutions containing 0.2 M CuCl2, 0.2 M CuCl2 + 0.4 M MnCl2, and 0.2 M CuCl2 +0.2M MnCl2 and calcination at 600°C (Fe2+ to Fe3+conversion of 66, 67, and 75%, respectively). The copper–manganese mixed oxide catalysts consist of CuO, MnO2, Ca2Mn3O8, Ca3CuMnO6, and Cu1.5Mn1.5O4, and the copper oxide catalyst contains CuO. In contrast to the other materials, the most active catalyst contains Cu1.5Mn1.5O4 (spinel structure) and has a unimodal mesopore volume–diameter distribution, with the most likely mesopore diameter of 26 nm. These factors seem to be responsible for its enhanced catalytic activity.