Antifouling ultrafiltration membranes based on acrylic fibers waste/nanochitosan for Congo red and crystal violet removal

In this study, acrylic fibers waste blended with different ratios of nanochitosan (0.5%, 1%, 2% and 4%, in weight) were converted into antifouling ultrafiltration nanocomposite membranes using a phase separation technique for the remediation of Congo red (CR) and crystal violet (CV) dyes from water. The fabricated nanocomposite membranes were investigated using Fourier Transform Infrared (FTIR), thermal gravimetric analysis (TGA), X-ray diffraction (XRD) and scanning electron microscope (SEM). The membrane hydrophilicity was estimated using contact angle measurements, which revealed that the 4% loaded nanochitosan had the highest hydrophilicity. Additionally, the water uptake, porosity, water contact angle and water flux of the nanocomposite membranes were assessed. The membrane filtration performances were explored for the removal of CR and CV as anionic and cationic dyes, respectively, at different concentrations and various applied pressures (1 bar to 4 bar). The experimental data revealed a high rejection (R) performance for CR (R≃100%) with a high water flux of about 150 L/(m²·h) to 183 L/(m²·h) for the optimized membrane with 2% nanochitosan at an applied pressure of 4 bar. The rejection for CV showed a variant rejection (70%–99%) at different dye concentrations with fluxes ranging from 93.6 L/(m²·h) to 149.5 L/(m²·h) for the same composite membrane. The composite membrane showed enhanced flux recovery after fouling by bovine serum albumin and was resistant to widespread gram-positive (Staphylococcus aureus) bacteria.

Graphical abstract