Selectivity Formula:
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Definition: Selectivity or Separation Factor is defined as the preferential uptake of the solute by the solvent over the carrier in liquid-liquid extraction processes.
Purpose: This calculator determines the selectivity using activity coefficients of components in both raffinate and extract phases.
The calculator uses the formula:
Where:
Explanation: The formula compares the relative distribution of solute versus carrier between the two phases.
Details: Selectivity determines the efficiency of separation in liquid-liquid extraction processes. Higher values indicate better separation.
Tips: Enter all four activity coefficients (must be > 0). The calculator will compute the selectivity factor.
Q1: What does a selectivity value of 1 mean?
A: A value of 1 means no separation occurs between solute and carrier.
Q2: What's considered a good selectivity value?
A: Values significantly greater than 1 (typically >2) indicate effective separation.
Q3: How are activity coefficients determined?
A: They can be obtained from experimental data or thermodynamic models like UNIQUAC or NRTL.
Q4: Does temperature affect selectivity?
A: Yes, temperature impacts activity coefficients and thus affects selectivity.
Q5: What if I get a selectivity less than 1?
A: This indicates the carrier is preferentially extracted over the solute - consider changing solvents.