Alfisol, Item 007:

IExFit, version 3.4 Fit adsorption data based on ion exchange reaction models. Display solid & liquid & gas phase speciation diagrams as a funciton of pH & redox conditions.

Why models? Main Welcome Program Information Select File Control Center (CC) CC: Database

CC-1: Enter Ions Present CC-2: Enter Initial Conditions CC: Add Solids CC: Add Gases CC: Add Ion Adsorption Data CC: Add Ion-Exchange Model CC-3: Run Aqueous Speciation CC-3: Run Model Fit Optimization

Tab: Model Optimization Tab: Options Tab: f(pH) Mass Balance Tab: Adsorption Data Analysis Tab: f(pH) Adsorbed Tab: f(pH) Aqueous Tab: f(pH) Solids Tab: f(pH) Gases Tab: pe-pH Tab: Titration

Step 3: Run Model Fit Optimization - Tab: Adsorption Data Analysis

Click on the "Ads. Data Analysis" tab to view the goodness-of-fit of each data point in the graph with the model-generated prediction. The pseudo-R² value (Efron's Coefficient of Determination) of each of the curves generated are also given. This tab is not shown if there was no model entered in the Control Center.

In the example below, the proton adsorption data were collected using the Backtitration Technique (Schulthess & Sparks, Soil Sci. Soc. Am. J., 1986).