What does the Langmuir isotherm show?

What does the Langmuir isotherm show?

The Langmuir isotherm describes the maximum amount of gas that a shale can hold at a specified pressure and temperature. Several factors may result in a shale holding less than the maximum amount of gas as represented by the isotherm. Such shales are termed undersaturated.

What are the three assumptions of the Langmuir isotherm?

The Langmuir adsorption isotherm was derived by the US chemist Irving Langmuir (1881–1957), using the kinetic theory of gases and making the assumptions that: (1) the adsorption consists entirely of a monolayer at the surface; (2) there is no interaction between molecules on different sites and each site can hold only …

How do you plot Langmuir isotherm?

ce/qe = 1/qm KL + ce/qm , where ce is the equilibrium concentration of the adsorbate and qe is the adsorption capacity adsorbed at equilibrium, qm is maximum adsorption capacity and KL is the Langmuir adsorption constant.

What is Langmuir constant?

The Langmuir constant (K) indicates the extent of interaction between adsorbate and the surface. If the value of K is relatively larger it indicates that there is a strong interaction between adsorbate and adsorbent while smaller value implies a weak interaction.

Why is the Langmuir isotherm important?

For example qm from Langmuir isotherm is very important when you design your batch system for wastewater treatment. Rl from the same isotherm give an indication about the favorability of the adsorption system. From D-R model you can identify the type of adsorption; physical or chemical.

What is the significance of Langmuir constants?

What is the Langmuir isotherm constant?

How do you derive Langmuir adsorption isotherm?

Derivation of the Langmuir isotherm

1. [SA] is proportional to the surface coverage of adsorbed molecules, or proportional to q.
2. [S] is proportional to the number of vacant sites, (1 – q)
3. [A] is proportional to the pressure of gas, P.

How is Langmuir equation at high pressure?

A) xm=aP1+bP.

What is the difference between Langmuir isotherm and Freundlich isotherm?

The key difference between Freundlich and Langmuir adsorption isotherms is that Freundlich adsorption isotherm is empirical, whereas Langmuir adsorption isotherm is theoretical. The adsorption isotherm is a primary method that we can use to predict the adsorption capacity of a particular substance.

Which is better Langmuir or Freundlich adsorption isotherm?

Freundlich adsorption isotherm. This equation implies that if one makes a log-log plot of adsorption data, the data will fit a straight line. The Freundlich isotherm has two parameters while Langmuir’s equations has only one: as a result, it often fits the data on rough surfaces better than the Langmuir’s equations.

When did Freundlich write the adsorption isotherm equation?

In 1909, Freundlich expressed an empirical equation for representing the isothermal variation of adsorption of a quantity of gas adsorbed by unit mass of solid adsorbent with pressure. This equation is known as Freundlich Adsorption Isotherm or Freundlich Adsorption equation or simply Freundlich Isotherm.

How does the Langmuir adsorption model explain desorption?

The Langmuir adsorption model explains adsorption by assuming an adsorbate behaves as an ideal gas at isothermal conditions. According to the model, adsorption and desorption are reversible processes.

How is the Langmuir model different from the kinetic model?

The difference between the kinetic and thermodynamic derivations of the Langmuir model is that the thermodynamic uses activities as a starting point while the kinetic derivation uses rates of reaction. The thermodynamic derivation allows for the activity coefficients of adsorbates in their bound and free states to be included.

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