Novel polyether sulfone/polyethylenimine grafted nano-silica nanocomposite membranes: Interaction mechanism and ultrafiltration performance

In the current work, we report a novel low fouling mixed matrix membranes (MMMs) that comprise polyethylenimine coated silica nanoparticles (SiO2-g-PEI) and polyethersulfone membrane for Ultrafiltration application. The hydrophilic SiO2-g-PEI was synthesized via grafting polyethylenimine (PEI) molecules onto the surfaces of silica nanoparticles (SiO2 NPs). Later on, NPs were embedded within a PES polymeric matrix at disparate ratios by the phase inversion method to obtain modified MMMs. Modified SiO2-g-PEI were characterized by Fourier transform infrared spectroscopy (FTIR), Field Emission Scanning electron microscopy (FESEM) and energy dispersive X-ray (EDX) spectroscopy, whereas the MMMs were characterized via FE-SEM, EDX, FTIR-ATR, and contact angle (CA). Moreover, this study presents the proposed interaction mechanism between the contents of PES/SiO2-g-PEI and the interaction mechanism of each PES/SiO2-g-PEI membrane with molecules of water. Results disclosed that MMMs prepared with 0.7 wt% nanoadditives possessed optimum characteristics and performance with 82.56% surface porosity, 41 +/- 2 degrees CA, and higher mean pore size (41.04 nm). The pure water permeation permeability of this membrane showcased more than 7-fold enhancement with 97% retention to BSA if compared to pristine PES. Besides, the M0.7 manifested a stable performance during the prolonged operation, greater flux recovery ratio (94%) and was less prone to fouling by the protein solution. These results significantly override those obtained by pristine PES membrane and suggest a promising potential of SiO2-g-PEI on tailoring membrane performance.

Automated summary

In this study, a novel low fouling mixed matrix membrane (MMMs) composed of polyethylenimine coated silica nanoparticles and polyethersulfone membrane was developed. The modified membrane exhibited improved performance and resistance to fouling compared to the pristine membrane.