Abstract <p>In this paper, SiO₂ xerogel has been synthesized by neutralizing sodium silicate with hydrogen sulfide and its adsorption properties for copper(II) ion removal have been studied with allowance for its morphological and structural characteristics. The synthesized adsorbent has been characterized using electron microscopy, high-resolution transmission microscopy, infrared spectroscopy, and energy-dispersive analysis. The specific surface area of the synthesized SiO₂ xerogel has been 145 m²/g, while the monolayer volume has been 34 cm²/g. The dependence of the adsorption characteristics of the synthesized SiO₂ xerogel on pH has been studied and the mechanism of ion exchange and saturation time have been identified. Maximal adsorption efficiency has achieved at pH 4–5, with the process occurring rapidly within the first 20 min. The adsorption isotherms have corresponded to the Langmuir model. The thermodynamic and kinetic aspects of copper(II) ion adsorption on the synthesized SiO₂ xerogel have been studied. Kinetic analysis has shown that the pseudo-second-order model has better described the adsorption of copper(II) ions on SiO₂ xerogel. The mechanism of copper(II) ion adsorption on SiO₂ xerogel has been considered.</p>