Heterogeneous photocatalytic processes that use semiconductor photocatalysts on the nanoscale have become a key technological solution to problems caused by wastewater. Textile wastewater, which mostly releases azo dyes into nature, dramatically affects the aquatic ecosystem because they reduce the penetration of daylight in waters. Eriochrome black T is an azo dye extensively used in the textile industry for dyeing silk, nylon, and wool and it is classified as a toxic compound due to its carcinogenic nature. In recent years, the development of nanotechnology enables the modification of metal oxides specific properties. Cerium(IV) oxide nanoparticles doped with copper (10, 20, 30 % Cu:CeO2) and manganese (10, 20, 30 % Mn:CeO2) were successfully obtained by hydrothermal synthesis and characterized by the XRD method, HRTEM micrographs and N2 adsorption-desorption isotherms. XRD crystallite sizes range from 3.3 to 4.3 nm, and specific surface areas range from 188 to 222 m^2 g^-1. HRTEM micrographs confirm that most particles are composed of a single nanoscale crystal. The adsorption and photocatalytic properties of the samples were determined by UV-Vis spectroscopic measurements. It was found that sample doping enhances the degradation results of Eriochrome black T (EBT). The kinetics of adsorption corresponds to pseudo-second order process, while the kinetics of the photocatalytic reaction corresponds to pseudo-first order process.