Denitrification of drinking water in poly (vinyl alcohol) pellets by reduction with the aid of hydrogen and Pd/Cu catalyst particles, which were immobilized inside the pellet, was modeled by the Stefan-Maxwell approach. Pure diffusivities of potassium nitrate were calculated using Molecular Dynamics. To obtain effective diffusion coefficients, the structure of a cryogel was first simulated by the ISING-model on a cubic lattice. The diffusion coefficients then result-from the following lattice gas Monte Carlo simulation.