Question

What form Freundlich Adsorption Equation will take at a higher pressure?

Answer 1

1. The variation in the amount of gas adsorbed by the adsorbent with pressure at constant temperature can be expressed by the means of a curve termed an adsorption isotherm.
2. Freundlich gave an empirical relation between the quantity of gas adsorbed by unit mass of solid adsorbent and pressure at a particular temperature.
3. Freundlich adsorption isotherm is given by - $\frac{\mathrm{x}}{\mathrm{m}}=k{p}^{\frac{1}{n}}$
4. Where, x is the mass of gas adsorbed on mass m, p is the pressure and k and n are the constants that depend on the nature of gas or adsorbent.
5. At a fixed pressure, there is a decrease in physical adsorption with an increase in temperature.
6. When $\frac{1}{\mathrm{n}}$goes to zero, $\frac{\mathrm{x}}{m}=k{p}^{\mathit{0}}$the adsorption is independent of pressure.
7. When $\frac{1}{\mathrm{n}}=1,\frac{x}{m}=kp$the adsorption varies directly with pressure.
8. The experimental isotherms always seem to approach saturation at high pressure.
9. This cannot be explained by the Freundlich isotherm. Thus it fails at high pressure.