Question

Concentration at the surface of the spherical catalyst will be higher than the inside of the catalyst.

(a) True

(b) False

This question was addressed to me in an internship interview.

This intriguing question comes from Internal Mass Transfer and Reaction topic in portion Heterogenous Reactions of Bioprocess Engineering

Answer 1

The correct answer is (a) True

To explain: Concentration at the pore mouth will be higher than that inside the pore, .i.e., internal diffusion which is diffusion of reactants or products from particle surface (pore mouth) to pellet interior. And Mole balance over the shell thickness Δr is: IN – OUT + GEN = ACCUM.