Polybenzimidazole Membrane Crosslinked with Epoxy-Containing Inorganic Networks for Organic Solvent Nanofiltration...

Area of Science:

• Materials Science
• Chemical Engineering
• Separation Science

Background:

• Polybenzimidazole (PBI) membranes are crucial for organic solvent nanofiltration (OSN).
• Improving the chemical and pH stability of PBI membranes is essential for broader OSN applications.
• Existing PBI membranes often lack sufficient stability in harsh chemical environments, particularly at high pH.

Purpose of the Study:

• To develop a novel PBI-based OSN membrane with superior stability under high pH conditions.
• To enhance the chemical resistance of PBI membranes through crosslinking with a silane precursor.
• To evaluate the performance and stability of the developed membrane in basic organic solvent environments.

Main Methods:

• Crosslinking of pristine PBI membranes using 3-glycidyloxypropyl trimethoxysilane (GPTMS).
• Formation of organic-inorganic networks via hydrolysis and condensation of GPTMS.
• Reaction between epoxy end groups of GPTMS and amine groups of PBI for crosslinking.
• Characterization of membrane stability in organic solvents and basic solutions (pH 13).
• Performance evaluation including ethanol permeance and eosin Y rejection under operational pressure.

Main Results:

• The crosslinked PBI membrane exhibited excellent stability in organic solvents and remained undecomposed even at pH 13.
• The membrane achieved an ethanol permeance of 27.74 LMH/bar and a high eosin Y rejection (>90%) at room temperature and 10 bar.
• The membrane remained operational under extremely basic conditions, with a slight pore size enlargement due to swelling.
• The developed membrane demonstrates significant improvements in chemical and pH stability compared to pristine PBI.

Conclusions:

• The novel crosslinked PBI membrane offers exceptional stability in high pH and organic solvent environments.
• This membrane is a highly promising candidate for organic solvent nanofiltration applications, especially under challenging basic conditions.
• The crosslinking strategy effectively enhances the durability and applicability of PBI membranes in demanding separation processes.