Among the methods for the contaminated water treatment for removing heavy metal ions, including those of T1, the most widely used are the adsorption methods, and among the sorbents used, the different types of carbon materials. The analysis of the metal ion sorption mechanisms from aqueous solutions of carbon materials shows the essential role of surface oxygen groups present in all carbon materials (commercial products) for the sorption process. In the presented publication, the possibility was investigated through liquid phase oxidation with nitric acid to prepare oxidized carbon materials which differ both in the parameters of the adsorption texture and the content of surface oxygen groups on the carbon surface. The efficiency of the modified samples prepared by liquid phase oxidation for Tl ions sorption from aqueous medium was investigated by adsorption process. Increased sorption possibilities were observed towards Tl ions as compared to initial carbon materials.