Question

In the below equation, what does “D” represents?

(a) Length of the membrane

(b) Distance

(c) Diffusion

(d) Thickness of the membrane

The question was posed to me by my college director while I was bunking the class.

My query is from Role of Diffusion in Bioprocessing topic in portion Mass Transfer of Bioprocess Engineering

Answer 1

Correct option is (d) Thickness of the membrane

The explanation is: It states that the rate of diffusion of a gas across a membrane is:

▪ Constant for a given gas at a given temperature by an experimentally determined factor, K.

▪ Proportional to the surface area over which diffusion is taking place, A.

▪ Proportional to the difference in partial pressures of the gas across the membrane, P2 – P1.

▪ Inversely proportional to the distance over which diffusion must take place, or in other words the thickness of the membrane, D.