Massatransmissie is described by Fick’s laws of diffusion, which relate the mass flux to the concentration gradient and the diffusivity of the species. In practice the overall rate at which a species is transferred depends on two main steps: a driving force that creates a difference in chemical potential, and a transport resistance that limits the flow. The driving force can be a concentration difference, a temperature gradient or an external pressure, whereas the resistance is mainly determined by the properties of the phases involved and the interface geometry.
Primary mechanisms of massatransmissie include molecular diffusion, where molecules move randomly from high to low concentration, and convective transport, where bulk fluid motion carries the species. In many practical applications, such as liquid–liquid extraction or gas–liquid absorption, the two mechanisms act simultaneously and their combined effect is quantified by a mass transfer coefficient. The coefficient can be calculated from empirical correlations that incorporate factors such as viscosity, diffusivity, turbulence intensity and the geometry of the contacting surface.
Key parameters that characterize massatransmissie are the mass transfer coefficient, the interfacial area, and the boundary layer thickness. These variables are used to predict the rate of mass exchange in processes ranging from distillation columns and membrane separations to heat exchangers and chemical reactors. Accurate estimation of massatransmissie is therefore critical for optimizing energy use, ensuring product purity and controlling reaction kinetics.
Massatransmissie also plays an important role in environmental engineering, where it describes pollutant transport through soil, air or water. In this context it is monitored to evaluate the extent of contamination and to design remediation strategies. In biological systems, massatransmissie corresponds to nutrient uptake by cells and gas exchange across membranes, providing a bridge between chemical engineering principles and physiological processes.