The effect of HS− ions in 1 mol/dm3 NaOH solutions on the ion diffusion in wood calculated by combining the drift speed and the steady state ion diffusion

Diffusion tests through wood were made with different HS− concentrations in 1 mol/dm3 NaOH solutions. The molar conductivity at infinite dilution of these mixtures was measured. The porosity of northern pine (Pinus sylvestris), birch (Betula verrucosa) and spruce (Picea abies) was also measured. The model used in the calculations was a combination of the drift speed and steady state diffusion and was dependent on the porosity of the porous plug. Both the theoretical and the experimental diffusion model were found to describe the diffusion of ion combinations well. This indicates that the diffusion is directly dependent on the conductivity of the electrolyte. The apparent porosity and the membrane resistance were dependent of the HS− concentration. The chemical interaction between wood and solution was shown to be measurable as deviations in apparent porosity.