Selectivity Formula:
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Definition: Selectivity (β) measures how effectively a solvent extracts the solute from the carrier liquid in a liquid-liquid extraction process.
Purpose: It quantifies the solvent's preference for the solute over the carrier liquid, helping engineers design and optimize separation processes.
The calculator uses the formula:
Where:
Explanation: The ratio of solute to carrier in the extract phase is divided by the same ratio in the raffinate phase.
Details: High selectivity values (>1) indicate effective separation, while values near 1 suggest poor separation. Values <1 indicate the solvent prefers the carrier over the solute.
Tips: Enter mole fractions (values between 0 and 1) for all four components. The calculator will compute the selectivity factor.
Q1: What does a selectivity of 2 mean?
A: A selectivity of 2 means the solute is twice as likely to be extracted into the solvent phase as the carrier liquid.
Q2: What's considered good selectivity?
A: Generally, values >5 are considered good for industrial applications, though this depends on the specific process economics.
Q3: Can selectivity be less than 1?
A: Yes, if the solvent prefers the carrier liquid over the solute, resulting in β < 1 (undesirable for extraction).
Q4: How does temperature affect selectivity?
A: Temperature can significantly impact selectivity as it changes the relative solubilities of components in each phase.
Q5: What's the difference between selectivity and distribution coefficient?
A: The distribution coefficient relates to a single component, while selectivity compares the distribution of two components.