Background <p>The safe disposal of radioactive waste requires meticulously engineered containment systems to prevent the release of hazardous radionuclides into the environment and protect human populations. A key component of these systems is the liner, particularly in multilayer configurations designed to enhance containment efficiency. Clay liners, especially those incorporating bentonite, serve as critical barriers by immobilizing contaminants and restricting leachate migration. This study evaluates the suitability of bentonite as a barrier liner material for the sequestration of cesium (Cs) and cobalt (Co) radionuclides through a comprehensive analysis integrating experimental sorption studies, kinetic modeling, and statistical physics approaches.</p> Results <p>Batch sorption experiments were performed to quantify Cs and Co uptake by bentonite under varying conditions of pH, temperature, and initial ion concentration. Fractal kinetic models were employed to describe time-dependent sorption behavior, emphasizing the role of fractal-like surface properties of bentonite’s on sorption kinetics. The experimental saturation capacities for Cs were determined to be 8.01, 8.35, and 8.98&#xa0;mmol/kg, while those for Co were 8.86, 9.27, and 9.61&#xa0;mmol/kg at 298, 313, and 333&#xa0;K, respectively. Statistical physics modeling provided insights into the equilibrium sorption mechanisms, revealing multi-molecular sorption characterized by a steric parameter n &gt; 1 in the best-fitted monolayer model with two energy sites (R² &gt; 0.996). This suggests that Cs⁺ and Co²⁺ ions adopt a vertical orientation at two distinct active sites, with their interactions primarily governed by van der Waals forces, hydrogen bonding, and electrostatic attractions. The robustness of bentonite for radionuclide sorption was further validated by fractal-like pseudo-second-order kinetic modeling (R² &gt; 0.96), confirming the presence of energetic heterogeneity. Additionally, hydrodynamic dispersion coefficients were estimated using the Brigham model, offering valuable insights into solute transport dynamics. A preliminary assessment of radionuclide migration through the bentonite liner was conducted via analytical modeling, wherein the Ogata and Banks solution, coupled with nonlinear fitting analysis, reliably predicted ion transport trends.</p> Conclusion <p>These findings collectively reinforce the feasibility of bentonite as an effective liner material for radioactive waste containment, demonstrating its high sorption capacity and transport-limiting characteristics essential for long-term environmental protection.</p>