In reverse osmosis, what are the two components of the permeate and retentate?

In reverse osmosis, what are the two components of the permeate and retentate?

• A. Permeate: Water and ethanol; Retentate: Aromatic compounds of wine
• B. Permeate: Aromatic compounds of wine; Retentate: Water and ethanol
• C. Permeate: Water only; Retentate: Ethanol and water
• D. Permeate: Water and ethanol; Retentate: Grape solids

Answer: (A)

In reverse osmosis the membrane separates a solvent from solutes by letting the solvent (and some small molecules) pass through to the permeate, while larger solutes are retained in the retentate. In wine applications, water and small molecules like ethanol can cross the membrane, so they appear in the permeate, while the larger aromatic compounds that give wine its flavor stay behind in the retentate. That’s why the permeate is considered to be water and ethanol, and the retentate contains the aromatic compounds of wine. The other options mix up which components are small enough to pass or are retained, or omit ethanol from the permeate when it typically crosses the membrane.

In reverse osmosis the membrane separates a solvent from solutes by letting the solvent (and some small molecules) pass through to the permeate, while larger solutes are retained in the retentate. In wine applications, water and small molecules like ethanol can cross the membrane, so they appear in the permeate, while the larger aromatic compounds that give wine its flavor stay behind in the retentate.

That’s why the permeate is considered to be water and ethanol, and the retentate contains the aromatic compounds of wine. The other options mix up which components are small enough to pass or are retained, or omit ethanol from the permeate when it typically crosses the membrane.