Question

What is the Freundlich adsorption isotherm? Illustrate it with a graph.

Describe the Freundlich adsorption isotherm.

Answer 1

Freundlich adsorption isotherm is an empirical relation between the amount of gas adsorbed per unit mass of adsorbent `(x/m)` and the equilibrium pressure (P) at constant temperature. It is expressed as:

`x/m = kP^(1//n)`,

where (k) and (n) are constants.

When `(x/m)` is plotted against (P), a curved plot is obtained.

A graph of  log `x/m` versus log (P) gives a straight line, indicating the relationship.

This is used to describe adsorption at low pressures and helps find constants (k) and (n).