Question

Membrane separation processes are driven mainly by:

• A. Temperature difference
• B. Concentration or pressure difference
• C. Density difference
• D. Surface tension difference

Hint:

Logic Tip: Think of pushing water through a microscopic sieve (Pressure difference) or letting tea steep through a bag into water (Concentration difference). These two forces do almost all the work in membrane systems.

Answer 1

The Correct Option is B

Concept:
Membrane separation technologies (like reverse osmosis, dialysis, and gas separation) rely on a selectively permeable barrier. To force a substance through this barrier, a specific thermodynamic driving force must be applied.

Step 1: A membrane is designed to allow certain molecules or ions to pass through while physically or chemically blocking others.

Step 2: In pressure-driven processes like Reverse Osmosis (RO) or Ultrafiltration, a mechanical pump applies a high pressure difference across the membrane to force the solvent through.

Step 3: In processes like dialysis or pervaporation, the separation is driven by a concentration gradient, where species naturally move from an area of high concentration to an area of low concentration.

Step 4: While temperature and density can affect fluid properties, they are not the primary forces used to push molecules through separation membranes in standard industrial operations.

Step 5: Therefore, the fundamental operation of membrane separation processes is driven mainly by either a concentration or pressure difference.