Is diffusion same as mass transfer?

Is diffusion same as mass transfer?

Mass transfer is the movement of mass from one place to another. Diffusion is a form of mass transfer. The main difference between mass transfer and diffusion is that mass transfer may or may not occur across a concentration gradient whereas diffusion occurs across a concentration gradient.

What are the three types of mass diffusion?

Depending on the conditions, the nature, and the forces responsible for mass transfer, four basic types are distinguished: (1) diffusion in a quiescent medium, (2) mass transfer in laminar flow, (3) mass transfer in the turbulent flow, and (4) mass exchange between phases.

How mass transfer takes through diffusion and convection?

Convective mass transfer is really diffusion (the random movement of molecules) in combination with advection (molecules being carried along with the motion of the fluid). To better understand mass transfer via convection, it is important to consider boundary layers in fluids flowing over surfaces.

What is mass transfer in chromatography?

In chromatography: Plate height. (3) Nonequilibrium or mass transfer, in which the slowness of diffusion in and out of the stationary and mobile phases causes fluctuations in the times of residence of the solute in the two phases and a consequent peak broadening.

What is molecular diffusion in mass transfer?

• Molecular Diffusion 1. It is the movement of mass from a higher to a lower concentration due to random molecular motion. 2. It is described by Fick’s law (Eqn. 10.18) which states that the flux of a mass species is proportional to the concentration gradient of that species.

How does mass affect chromatography?

Larger molecules take longer to move up the chromatography paper or TLC plate, whereas smaller molecules are more mobile. Likewise, the polarity of the molecules can affect how far the spots travel, depending on the type of solvent used.

What is mass transfer HPLC?

Mass transfer, the C term, is the movement of analyte, or transfer of its mass, between the mobile and stationary phases. Through this type of diffusion, increased flows have been observed to widen analyte bands, or lower peak efficiencies.

What is dispersion in mass transfer?

Dispersive mass transfer, in fluid dynamics, is the spreading of mass from highly concentrated areas to less concentrated areas. It is one form of mass transfer.