It was studied the natural waters self-purification capacity in the presence of antraquinone dye RB4, copper (II) ions and hydrogen peroxide, that takes place only in catalytic way. For studying the self-purification process in the same conditions as in natural waters, it were added some compounds such as ammonium, oxalate and humate ions in the model systems. It was demonstrated that the ammonium ions catalyses the oxidation process, while the oxalates and humates inhibit it.
