Tunable Ion Selectivity in Self-Standing Protein-Based Membranes via Strategic Chemical Functionalization.

Area of Science:

• Materials Science
• Biomaterials
• Separation Science

Background:

• Protein-based biomembranes offer sustainable and tunable platforms for ion transport.
• Chemical functionalization can enhance the ion selectivity of these biomembranes.

Purpose of the Study:

• To chemically functionalize bovine serum albumin (BSA) membranes via sulfonation and phosphorylation.
• To evaluate the impact of functionalization on ion selectivity and transport properties.
• To explore the potential of tailored BSA membranes for ion separation and water purification.

Main Methods:

• Chemical functionalization of self-standing BSA membranes using sulfonation and phosphorylation.
• Structural and spectroscopic analyses to confirm functionalization and morphology.
• Electrochemical and radiotracer-based studies to assess ion transport performance.

Main Results:

• Phosphorylation increased water uptake and ion exchange capacity, creating a hydrated network with high ionic conductivity.
• Sulfonation reduced water uptake but moderately increased ion exchange capacity, yielding a compact structure with restricted ion mobility.
• Both membranes showed superior monovalent ion selectivity; phosphorylated BSA excelled in Cs+/Eu3+ separation, while sulfonated BSA enhanced Cs+/Ba2+ discrimination.

Conclusions:

• Chemically tailored BSA membranes offer tunable and highly selective ion transport.
• Functionalization strategies significantly influence membrane properties and ion selectivity.
• These findings support the development of sustainable technologies for advanced ion separation and water purification.