Advances in Chemical Engineering & Technology

Mass Transfer as Separation Processes

The driving force for mass transfer is typically a difference in chemical potential, when it can be defined, though other thermodynamic gradients may couple to the flow of mass and drive it as well. A chemical species moves from areas of high chemical potential to areas of low chemical potential. Mass transfer is used by different scientific disciplines for different processes and mechanisms. Mass transfer occurs in many processes, such as absorption, evaporation, drying, Crystallization, membrane filtration, and distillation. Distillation is a widely used method for separating mixtures based on differences in the conditions required to change the phase of components of the mixture. Absorption is the process in which a fluid is dissolved by a liquid or a solid (absorbent). Adsorption is the process in which atoms, ions or molecules from a substance (it could be gas, liquid or dissolved solid) adhere to a surface of the adsorbent.