ABSTRACT
Aeration, absorption, and stripping are unit operations that rely on flow of masses between phases. When a difference in concentration exists between two points in a body of mass, a flow of mass occurs between the points. When the flow occurs between two phases of masses, a transfer of mass between the phases is said to occur. This transfer of mass between phases is called
mass transfer
. Examples of unit operations that embody the concept of mass transfer are distillation, absorption, dehumidification, liquid extraction, leaching, and crystallization.
