Kinetic study of diiodine adsorption behavior on the epoxy paint in PWRs

Abstract

To study the adsorption of diiodine on epoxy paint in PWR under severe accident scenarios, a series of adsorption experiments was performed. The adsorption follows the pseudo-second-order kinetic law. The adsorption rate constant \({k}_{2}\) is 1.6 × 10^–3 to 3.3 × 10^–3 g mg⁻¹ h⁻¹, and the saturation adsorption capacity \({q}_{e}\) is 10.9 to 31.3 mg g⁻¹. Relative humidity significantly impacts adsorption rates, while temperature affects saturation capacity. IR, TG-DSC, and SEM–EDS characterizations suggest that I₂ interacted with amide groups in the epoxy paint, forming pyrolytic compounds. These results provide useful data for severe accident management.