The focus of this contribution is on numerical simulation of processes with moving deformable interfaces involving soluble surfactants. Resolution of the interface is done by the Volume-of-Fluid-method. The current numerical approach is limited to diffusion controlled processes, where the relation between the area-specific surfactant concentration on the interface and the volume-specific concentration in the sub-layer adjacent to the interface is given by an adsorption isotherm. The change in time of the amount of surfactants within a fixed control volume containing interface is determined by diffusive and convective fluxes both on the interface and in the bulk phase and by advection of the interface itself. For a conservative discretisation of the interfacial fluxes, a reconstruction of the interface by means of a continuous iso-surface with respect to the VOF-variable is used.