Adsorption isotherms are essential for the description of how pollutants’ concentration will interact with adsorbent surfaces and are useful to optimize the use of adsorbents for the removal of pollutants from aqueous solutions (Emmanuel and Rao, 2008).

What is adsorption isotherm Class 12?

Adsorption isotherm is the variation of the mass of the gas (adsorbate) adsorbed per gram of the adsorbent with pressure at constant temperature. The Freundlich adsorption isotherm is the mathematical representation for the variation of the extent of adsorption (x/m) with pressure (P) at a given temperature.

What is the limitation of Freundlich adsorption isotherm?

Limitations of Freundlich Isotherm Freundlich isotherm only approximately explains the behaviour of adsorption. The value of 1/n can be between 0 and 1, therefore the equation holds good only over a limited range of pressure. When 1/n = 0, x/m is constant, the adsorption is independent of pressure.

What will be the Freundlich adsorption isotherm at high pressure?

Freundlich adsorption isotherm At high pressure 1/n = 0, hence extent of adsorption becomes independent of pressure.

Which is the best definition of adsorption isotherm?

Definition of adsorption isotherm. : a curve obtained by plotting at constant temperature the quantity of adsorbate against the concentration of the substance in the original gas or solution.

When does the Freundlich adsorption isotherm fail?

Adsorption isotherm is a curve that expresses the variation in the amount of gas adsorbed by the adsorbent with the temperature at constant pressure. Freundlich isotherm fails at high pressure.

How is the Langmuir adsorption isotherm related to surface coverage?

The Langmuir adsorption isotherms predict linear adsorption at low adsorption densities and a maximum surface coverage at higher solute metal concentrations. The Langmuir adsorption isotherm has the form: X/M = abc(l + ac) where. X is the weight of a solute sorbed by M grams of solid,

Can a Freundlich isotherm work at high pressure?

At high pressure, the experimental isotherms always seem to approach saturation. Freundlich isotherm does not explain this observation and therefore, fails at high pressure. The Freundlich isotherm was followed by two other isotherms – Langmuir adsorption isotherm and BET adsorption isotherm.