Dear Lucas Silva

If you consider the limiting case where the partial pressure of component i is zero, the fractional occupancy should be zero, regardless of total pressure. This means that you need to use partial pressure of component i.

All the best

Johan

Dear Lucas

Modelling adsorption isotherms presumes equilibrium between the gas phase and the adsorbed phase, i.e. the chemical potential of each component in the adsorbed phase will be equal to the chemical potential of that same component in the gas phase. The chemical potential of a component in the gas phase depends on its activity and thus its partial pressure. Hence, you must correlate (at low pressure) the measured uptake with the partial pressure in the gas phase.  

Eric

You must use the partial pressure of the gas versus Pa versus the fraction of of sites of the adsorbent covered by the material thet a you can find your answer here or by logging into YouTube for further explanation

https://en.wikipedia.org/wiki/Langmuir_adsorption_model

It depends on what is adsorbed. If a component of the gas mixture is to be separated from the mixture via adsorption, then the adsorption capacity should be defined in terms of the partial pressure of that component. However, if the entire mixture of the gas is to be removed from a system containing other components, then the total pressure of the mixture (under reference) should be used.

Lucas,

Wikipedia has a good description and equation for a Langmuir isotherm at:

https://en.wikipedia.org/wiki/Langmuir_adsorption_model

Regards, Jeff Amelse

You must always use the partial pressure.

Yes, you should use the partial pressure since you are considering equilibrium between the components. There are a lot of works people can find about the topic, also here in RG (e.g. Chapter Fundamentals of the Adsorption Theory

Here is link

https://youtu.be/wWIZyxrp04I