<p><span style="font-size:14px"><span style="font-family:Arial,Helvetica,sans-serif">Mesoporous silica was synthesized by a chemical process and its efficiency was investigated for removal of cobalt (Co²⁺) ions from contaminated water in a laboratory scale. The characteristics of synthesized mesoporous were analyzed by SEM/TGA. Optimal conditions were determined for important parameters such as solution pH, the absorbent dose, the initial Co²⁺ concentration, and contact time by a single-variable method through the batch experiments. The SEM results confirmed the synthesized silica had high porosity with a honeycomb-like structure. The results showed that with an increasing adsorbent dose and contact time to the optimum, the efficiency of Co²⁺ adsorption increased. However, with increasing concentration of Co²⁺, the removal efficiency decreased. At optimal contact time (8 h), 85 % of Co²⁺ was removed. The maximum adsorption efficiency at pH =7, initial Co²⁺ concentration of 5 ppm, and at the adsorbent dose 0.3 g/50 ml, was 89%. The study of adsorption isotherm and kinetic models showed that the adsorption process followed the Freundlich isotherm (R² = 0.9359) and the second-order kinetic model (R²=0.999). Therefore, the synthesized mesoporous silica presented a chemical adsorption mechanism for Co²⁺ removal from aqueous media and can be utilized in wastewater treatment containing divalent heavy metals such as Co²⁺.</span></span></p>