Effects of solvent and solute drag on transmembrane diffusion.

Area of Science:

• Membrane science and separation technologies
• Physical chemistry of interfaces
• Mass transport phenomena

Background:

• Understanding membrane transport requires quantifying forces like solvent drag and solute drag.
• Heteropore and homopore membranes exhibit distinct transport characteristics.
• The interplay between different drag forces influences separation efficiency.

Purpose of the Study:

• To compare and quantify solvent drag and solute drag forces in systems with heteropore and homopore membranes.
• To investigate how the direction of forces relative to tracer diffusion affects permeability.
• To determine the relative effectiveness of solute drag versus solvent drag.

Main Methods:

• Experimental quantification of solvent drag and solute drag forces.
• Utilizing systems with both heteropore and homopore membranes.
• Employing various solute pairs to confirm findings across different membrane types.

Main Results:

• Tracer solute permeability can be enhanced or reduced depending on the direction of solvent or solute flux relative to tracer diffusion.
• The forces can act additively or antagonistically, modifying their overall effect.
• Solute drag was found to be approximately 300 times more effective than solvent drag on a mole-to-mole basis in the studied system.

Conclusions:

• Both solvent drag and solute drag forces significantly impact membrane transport.
• Solute drag is a dominant force compared to solvent drag in specific membrane systems.
• These drag forces can be analyzed and manipulated in various membrane systems for optimized separations.