Abstract <p>The sorption capacity of the synthesized polymer based on carboxymethyl cellulose and glycidyl acrylate with respect to Cu²⁺, Ni²⁺, Fe²⁺, and Mn²⁺ ions has been studied. It is shown that the sorption of metal ions is reliably described by the Langmuir model, and the process itself is of a physical nature. A thermogravimetric analysis established that the thermal destruction of the polymer occurs in three stages, while the destruction of its complex with copper occurs in four stages. The activation energy of decomposition for each stage is 29–57 kJ/mol for the starting polymer and 58–120 kJ/mol for its complex with copper. The introduction of Cu(II) increases the thermal stability of the obtained polymer based on carboxymethyl cellulose.</p>