Covalent organic framework membrane on electrospun polyvinylidene fluoride substrate with a hydrophilic intermediate...

Area of Science:

• Materials Science
• Polymer Science
• Nanotechnology

Background:

• Electrospun membranes offer high porosity and low resistance but require functionalization for advanced applications.
• Covalent Organic Frameworks (COFs) show promise for membranes, yet their integration onto electrospun substrates is underexplored.
• PVDF electrospun membranes serve as robust substrates for composite material development.

Purpose of the Study:

• To synthesize and characterize novel COF composite membranes on electrospun PVDF substrates.
• To investigate the role of a graphene oxide and oxidized carbon nanotubes (GO-OCNTs) intermediate layer in enhancing membrane performance.
• To optimize the interfacial polymerization process for COF film formation.

Main Methods:

• Preparation of electrospun PVDF membranes.
• Fabrication of a GO-OCNTs intermediate layer via suction filtration.
• Interfacial polymerization to form a COF layer on the GO-OCNTs/PVDF substrate.
• Characterization of membrane properties including water permeance, dye rejection, and stability.

Main Results:

• The COF/GO-OCNTs/PVDF composite membranes exhibited improved water permeance and dye retention compared to membranes without the intermediate layer.
• An optimized membrane achieved a 97.1% rejection rate for Coomassie brilliant blue G250 (BBG-250) and a water permeability of 96.7 L m⁻² h⁻¹ bar⁻¹.
• The composite membranes demonstrated excellent chemical, mechanical, and long-term water permeation stability.

Conclusions:

• A novel method for preparing dense, defect-free COF films on electrospun substrates was successfully developed.
• The incorporation of a GO-OCNTs intermediate layer significantly enhances the performance of COF composite membranes.
• These findings pave the way for utilizing COF composite membranes in advanced separation applications.