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Amino acid rejection behaviour as a function of concentration
Jason Shirley1, Stephen Mandale, Paul M Williams
1Centre for Complex Fluid Processing, Swansea University, UK.
Advances in Colloid and Interface Science
|April 8, 2011
Summary
This study investigated amino acid rejection using nanofiltration. A steric/charge model explained some amino acids, but others showed complex behavior not explained by dimerization.
Area of Science:
- Membrane Science and Technology
- Separation Processes
- Biochemistry
Background:
- Nanofiltration is crucial for separating solutes.
- Amino acid behavior in nanofiltration is complex.
- Understanding rejection mechanisms is key for process optimization.
Purpose of the Study:
- To investigate the rejection behavior of five amino acids using a specific nanofiltration membrane.
- To evaluate the applicability of a combined steric and charge rejection model.
- To explore potential alternative mechanisms, such as dimerization, for unexplained rejection patterns.
Main Methods:
- Experimental investigation of solute rejection versus concentration for five amino acids.
- Application of a combined steric and charge rejection model.
- Dynamic light scattering and osmotic pressure measurements to assess molecular interactions.
Main Results:
- Lysine (at isoelectric point) and phenylalanine rejection were well-described by the steric/charge model.
- Glutamine, glutamic acid, and glycine showed complex rejection behavior not predicted by the model.
- Dynamic light scattering and osmotic pressure data did not support amino acid dimerization as the cause.
Conclusions:
- The steric/charge model is effective for some amino acids but insufficient for others.
- An un-identified process governs the rejection of certain amino acids at higher concentrations.
- Dimerization is unlikely to be the cause of the observed complex rejection behavior.
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