High performance antibiofouling hollow fiber polyethersulfone nanocomposite membranes incorporated with novel surface-modified silver nanoparticles suitable for membrane bioreactor application

Surface-modified silver nanoparticles with amine, thiol, carboxyl, and the thiol-polyvinylpyrroldidone (PVP) functional groups were synthesized as functional filler for nanocomposite membranes for mem-brane bioreactor (MBR), with the aims to enhance antimicrobial effect of silver, while immobilizing silver nanoparticles inside the matrix of the membrane. Analyses by fourier transform infrared (FTIR), field emission scanning electron microscopy (FESEM), and dynamic light scattering (DLS) proved successful surface modification for each type of nanoparticles, with average particle sizes of 69, 20, 33, and 34 nm for amine, carboxyl, thiol and thiol-PVP modified silver nanoparticles, respectively. Polyethersulfone (PES) based nanocomposite hollow fiber membranes showed different morphology and performance in ultrafiltration and MBR experiments. The surface modifications were able to immo-bilize silver nanoparticles inside the membrane by providing proper interactions between the nanopar-ticles and polymer, reducing silver release compared to the unmodified nanoparticles. Modified nanoparticles changed the phase inversion, resulting in different morphology and average pore size in the range of 7.6-28.0 nm. The surface-modified nanoparticles with enhanced antimicrobial activity improved antifouling properties of the nanocomposite membranes, leading to interesting MBR perfor-mance improvements, with 122 % increase of flux, 23 % increase of chemical oxygen demand (COD) removal and flux recovery by over 30 %.CO 2022 The Korean Society of Industrial and Engineering Chemistry. Published by Elsevier B.V. All rights reserved.