Abstract. Mesoporous SiO2 was synthesized via sol-gel technology under acidic conditions at 50°C. The surface of the obtained sorbents was modified with the amino acid L-cysteine, and their textural characteristics were investigated. After modification with L-cysteine, the specific surface area increased to 975.6 m²/g, and the nitrogen adsorption capacity reached 7.3 mol/kg. The adsorption of Cu²⁺ and Pb²⁺ cations on the sorbents was also studied. The adsorption capacities were found to be 0.41 mmol/l for Cu²⁺ and 0.73 mmol/l for Pb²⁺.