The focus of this contribution is on numerical simulation of processes with moving deformable interfaces involving soluble surfactants. Resolution of the interface is based on the Volume-of-Fluid (VOF)-method. An extended surface transport theorem is used for modelling the convective interface flux of the adsorbed surfactant. The numerical discretisation of terms relating to interfacial processes is based on an iso-surface concerning the VOF-variable as a connected approximation of the interface. The VOF method is applicable to diffusion controlled processes but not limited to a certain adsorption isotherm and surface equation of state. First numerical 3D - experiments on a bubble rising in a surfactant solution were done with the commercial CFD-solver Fluent 6.2. The expected surfactant distribution at the bubble interface and in the bulk phase could be obtained. The known formation of two vortices inside the bubble and the resulting retardation are also reflected.