Adsorption
Use this node to model adsorption of the fluid phase species onto the porous media surface of the fracture.
Matrix Properties
Use the Porous material list to define a material specifying the matrix properties on the current selection. By default the Boundary material is used as The Transport of Diluted Species Interface is active on boundaries only. The Density ρ of the porous media is needed when modeling adsorption to the surface of the porous matrix. By default the option From material is selected.
Adsorption
Select an Adsorption isotherm — Langmuir (the default), Freundlich, Toth, BET, or User defined to specify how to compute cP, the amount of species sorbed to the solid phase (moles per unit dry weight of the solid). Also activate the check box for the species ci for which adsorption takes place.
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For Langmuir:
Enter a Langmuir constant kL,c (SI unit: m3/mol) and an Adsorption maximum cp,max,c (SI unit: mol/kg):
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For Freundlich:
Enter a Freundlich constant kF,c (SI unit: mol/kg), a Freundlich exponent NF,c (dimensionless), and a Reference concentration cref,c (SI unit: mol/m3).
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For Toth:
and
Enter a Toth constant bT,c (SI unit: m3/mol), a Toth exponent NT,c (dimensionless), and an Adsorption maximum cp,max,c (SI unit: mol/kg).
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For BET (Brunauer-Emmett-Teller):
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Enter a BET constant KB,c (dimensionless), a Monolayer adsorption capacity c0,c (SI unit: mol/kg), and a Saturation concentration cS,c (SI unit: mol/m3).
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For User defined:
Enter an adsorption isotherm cP,c (SI unit: mol/kg).
For more information, see Adsorption in the theory section.
Further Reading
See the theory chapter in the section Mass Balance Equation for Transport of Diluted Species in Porous Media.