According to Freundlich, there is an empirical relationship between the amount of gas adsorbed by a unit mass of solid adsorbent and the pressure at a given temperature:
‌=k⋅p1∕n‌‌(‌ for ‌n>1)Here,
x represents the mass of gas adsorbed,
m is the mass of the adsorbent, and
p is the pressure. The constants
k and
n are specific to the system being examined.
By taking the logarithm of both sides of the equation, we have:
log‌=log‌k+‌‌log‌pTo verify the validity of the Freundlich isotherm, you can plot
log‌ on the y -axis and
log‌p on the
x-axis. If the plot forms a straight line, the isotherm is valid. If not, it indicates a lack of alignment with the Freundlich equation.