Modelling the charcoal canister with a diffusion barrier by finite difference method

The addition of a barrier can improve the performance of a charcoal canister in adsorption of radon since it takes up less water and more radon, and its integration time is longer. In this paper, we model the performance of a charcoal canister with a diffusion barrier by the finite difference method. The adsorption and diffusion effects, and the influence of water uptake are considered. Appropriate boundary conditions have also been determined. Using the implicit method of finite difference, the profile of radon concentration within the charcoal bed and the temporal change of adsorption of radon can be obtained. The results agree well with the experimental data.