Freundlich Adsorption Isotherm | Chemistry | Hindi / Urdu

The #Freundlich equation or Freundlich #adsorption #isotherm, an adsorption isotherm, is an empirical relationship between the quantity of a gas adsorbed into a solid surface and the #gas #pressure. The same relationship is also applicable for the concentration of a solute adsorbed onto the surface of a solid and the concentration of the solute in the liquid phase. In 1909, #Herbert Freundlich gave an expression representing the isothermal variation of adsorption of a quantity of gas adsorbed by unit mass of solid adsorbent with gas #pressure.[1] This equation is known as Freundlich adsorption isotherm or Freundlich adsorption equation. As this relationship is entirely empirical, in the case where adsorption behavior can be properly fit by isotherms with a theoretical basis, it is usually appropriate to use such isotherms instead (see for example the #Langmuir and #BET adsorption theories). The Freundlich equation is also derived (non-empirically) by attributing the change in the equilibrium constant of the binding process to the heterogeneity of the surface and the variation in the heat of adsorption.
The Freundlich adsorption isotherm is #mathematically expressed as
{\displaystyle {\frac {x}{m}}=Kp^{1/n}}
It is also written as
{\displaystyle \log {\frac {x}{m}}=\log K+{\frac {1}{n}}\log p}
or
{\displaystyle {\frac {x}{m}}=Kc^{1/n}}
It is also written as
{\displaystyle \log {\frac {x}{m}}=\log K+{\frac {1}{n}}\log c}
where
x = mass of adsorbate
m = mass of adsorbent
p = equilibrium pressure of the gaseous adsorbate in case of experiments made in the gas phase (gas/solid interaction with gaseous species/adsorbed species)
c = equilibrium concentration of adsorbate in case of experiments made with an aqueous solution in contact with a dispersed solid phase (dissolved species/adsorbed species).
K and n are constants for a given adsorbate and adsorbent at a given temperature (from there, the term isotherm needed to avoid significant gas pressure fluctuations due to uncontrolled temperature variations in the case of adsorption experiments of a gas onto a solid phase).
At high pressure 1/n = 0, hence extent of adsorption becomes independent of pressure.
The Freundlich equation is unique; consequently, if the data fit the equation, it is only likely, but not proved, that the surface is heterogeneous. The heterogeneity of the surface can be confirmed with calorimetry. Homogeneous surfaces (or heterogeneous surfaces that exhibit homogeneous adsorption (single site)) have a constant ΔH of adsorption.[4] On the other hand, #heterogeneous adsorption (multi-site) have a variable ΔH of adsorption depending on the percent of sites occupied. When the adsorbate pressure in the gas phase (or the concentration in solution) is low, high-energy sites will be occupied first. As the pressure in the gas phase (or the concentration in solution) increases, the low-energy sites will then be occupied resulting in a weaker ΔH of adsorption.
Learn more about Chemistry with Mr. Ghazanfar Iqbal.
Comment your queries.
---------------
Playlist: • What is Electrochemist...
-------------
Follow us on
Facebook: / echaarstudio
KZbin: / echaarstudio
Instagram: / echaarstudio
Blog: echaarstudio.b...
-----------------
#Chemistry #Adsorption #Isotherm

[@villageactivities8608]

very nice

[@ecHaaRStudio]

Thanks alot

[@inspirationalclub3916]

Good sir

[@ecHaaRStudio]

😊

[@villageactivities8608]

nice

[@ecHaaRStudio]

Thanks

[@nasseruldin6184]

Level hn gia 😍

[@ecHaaRStudio]

Shukrya 😊

[@hareemfatima6690]

👍👍

[@ecHaaRStudio]

Thanks