Synergistic modification of polyvinylidine fluoride membranes with multi-walled carbon nanotubes and triclosan for enhanced ultrafiltration performance

The performance of polyvinylidene fluoride (PVDF) ultrafiltration membranes is often restricted by hydrophobicity, biofouling, and limited selectivity. In this work, a chemically stabilized, dual-modified PVDF ultrafiltration membrane incorporating functionalized multi-walled carbon nanotubes (MWCNTs-COOH) and the first use of triclosan (TCS) was developed to enhance separation efficiency and antifouling performance. Epichlorohydrin (ECH)–mediated crosslinking enabled stable chemical integration of the functional additives, thereby improving structural integrity and performance durability. FTIR spectra confirmed successful incorporation of ECH and TCS, while TGA revealed enhanced thermal stability of M4 (up to ~ 700 °C) due to the aromatic nature of triclosan. SEM–EDX and AFM analyses showed increased surface roughness (Ra = 34.27 nm for M4 vs. 22.63 nm for unmodified PVDF), indicating effective surface modification. Contact angle measurements showed improved hydrophilicity (84.71° to 52.3°), attributed to enhanced surface polarity and cohesive polymeric interactions. The synergistic effects of MWCNTs-COOH, ECH crosslinking, and surface-immobilized triclosan translated into excellent ultrafiltration performance, with a stable permeability of 23.26 L m⁻2 h⁻1 and bovine serum albumin rejection exceeding 99%. Overall, the combined chemical stabilization and surface functionalization strategy yields a multifunctional PVDF membrane with enhanced selectivity, antifouling resistance, and operational stability, highlighting its potential for advanced ultrafiltration and wastewater treatment applications.