In many systems, species partition between media (e.g., water and sediment) according to a non-linear isotherm, in which the degree of partitioning varies with concentration. The Langmuir sorption isotherm is one of these non-linear isotherms that is available in GoldSim. Non-linear isotherms are introduced to GoldSim by linking the partitioning coefficient in the solid medium to the equation for the nonlinear isotherm (i.e. linking to an Expression element where the non-linear isotherm is calculated).
The Langmuir soprtion isotherm was developed with the concept that a solid surface possesses a finite number of sorption sites. When all sorption sites are filled, the surface will no longer sorb solute from solution. The calculation for the Langmuir sorption isotherm is in the "Materials" container.
To Open the Model File:
- Start GoldSim
- Click on the File and select Open Example...
- Browse to General Examples --> Contaminant Transport Examples
- Select the file called Langmuir.gsm