Bio‐Inspired Functionalization of Carbon Nanotubes and Their Effect on the Anti‐Fouling Properties of Polysulfone Ultrafiltration Membranes

ABSTRACT

The inherent hydrophobicity of polysulfone (PSf) membranes frequently leads to membrane fouling issues. To address this limitation, a novel composite membrane was developed by incorporating hydrophilic tannic acid‐modified carbon nanotubes (TCNT). The TCNT nanomaterial was synthesized by functionalizing carbon nanotubes (CNTs)─known for their exceptional organic compound adsorption capacity─with tannic acid (TA), which exhibits mussel‐inspired adhesion properties for surface modification. The TCNT/PSf composite membranes were fabricated via non‐solvent induced phase separation (NIPS). Characterization results demonstrated that increasing TCNT content enhanced membrane porosity, enlarged finger‐like pore structures, and improved surface hydrophilicity (reduced contact angle). The optimal membrane with 7 wt% TCNT loading achieved outstanding performance: 97% bovine serum albumin (BSA) rejection and 450 L m ⁻²  h ⁻¹ pure water flux (50% higher than the pristine PSf membrane's 300 L m ⁻²  h ⁻¹ ). Moreover, the total fouling ratio ( Rt ) significantly decreased from 84% to 53%, confirming the substantially improved antifouling properties of the TCNT‐modified PSf membranes. The biomimetic functionalization strategy of TA‐CNTs provides a new idea for the development of next‐generation anti‐pollution membrane materials, and its green modification method is in line with the concept of sustainable development.