Fabrication of CuO nanoparticles immobilized nanofiltration composite membrane for dye/salt fractionation: Performance and antibiofouling

The separation of dye/salt mixtures is a challenging task in treating high salinity textile industrial wastewater. Therefore, there is a need to develop highly permeable and antibiofouling membranes for efficient disposal of textile industrial effluents. Membrane-based separation is evolving as an alternative purification technology to the conventional energy intensive separation and purification processes. In the current work, a new loose nanofiltration membrane was fabricated through two rounds of interfacial polymerization on ultrafiltration polysulfone support by constructing copper oxide (CuO) nanoparticles (NPs) containing semi-Interpenetrating Network (semi-IPN) polyamide as an active layer. The newly constructed thin film nanocomposite loose nanofiltration membrane namely CuO/PA@PS/PET was thoroughly characterized by ATR-FTIR, FESEM, AFM, Zeta-potential, Water Contact Angle (WCA), EDX, elemental mapping and XRD. FTIR and FESEM analysis of the membrane showed the contribution of hydrophilic CuO NPs in the crosslinking event of the fabrication of semi-IPN active layer. The WCA was decreased from 78° in case of PS/PET to 62° CuO/PA@PS/PET. The CuO/PA@PS/PET showed exceptional performance in terms of flux of DI water reaching to > 140 L/m²h⁻¹ at 16 bars and > 99% rejection of Methylene Blue (MB) while allowing CaCl₂, MgCl₂ and NaCl to permeate through it. The incorporation of CuO NPs not only enhanced the water flux and rejection but it also developed antibiofouling features of the membrane as the CuO/PA@PS/PET showed bacteriostasis of E. coli and S. aureus upto 95.19% and 82.23%, respectively. Hence, the newly fabricated CuO/PA@PS/PET membrane can be an excellent choice for fractionating dye/salt mixtures with remarkable antibiofouling.