Desorption modelling in CADET

Dear CADET team,

I’m trying to model desorption in CADET, but I’m unsure how to set it up correctly. I understand how adsorption is modeled, and I have several simulated breakthrough curves for my target components with fitted parameters. However, these target components are in a 5% Ethanol solution but I define it as a single component system in CADET.

I use 30% Ethanol to desorb and from my experiments, I expect the desorption curve to show an initial peak due to the ethanol concentration difference driving the desorption.

How should I define this in CADET? Should I define ethanol as an additional component, and modify the isotherm parameters or is this done through events?

Any guidance would be greatly appreciated!

Thanks a lot in advance

Zubin

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Hello Zubin and welcome to the Forum!

The usual approach is to use a multi-component isotherm (such as the Mobile Phase Modulator Langmuir — CADET ).

However, the details depend on which Isotherm you are using to model adsorption and which adsorption type you are trying to describe (e.g. IEX, HIC, RPC)?

Best wishes,
Ron

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Thanks for the quick reply Ron.

I use Langmuir model to model adsorption, and my process is closer to RPC.

Excellent, in that case I think the Mobile Phase Modulator Langmuir — CADET is a good choice. You can use component 0 as Ethanol instead of as salt as it is described in the documentation.

Then the \beta parameter can be used to describe situations where a higher Ethanol concentration leads to weaker binding and will model the desorption and will need to be fitted to your data.

The \gamma parameter can be used to describe situations where a higher Ethanol concentration leads to stronger binding and should be set to 0 in your case.

Setting up load-wash-elute systems is described in this example and estimating binding model parameters is described in this example.

Let me know if you need further input.

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Fantastic. Thanks a lot for the help!

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