Biogenic silver nanoparticles (bio-Ag0) decrease biofouling of bio-Ag0/PES nanocomposite membranes

Abstract

Biofouling is a major problem for the application of membrane technology in water and wastewater treatment. One of the practical strategies to decrease biofouling is the use of advanced anti-biofouling membrane material. In this study, different amounts of biogenic silver nanoparticles (bio-Ag^{<font size="1">0</font>}) were embedded in polyethersulfone (PES) membranes, using the phase-inversion method. The effects of the bio-Ag^{<font size="1">0</font>} content on the structure of the membrane and its filtration performance were systematically investigated. The results demonstrated that silver-containing nanostructures were uniformly distributed on membrane surface. Bio-Ag^{<font size="1">0</font>} incorporation slightly increased the hydrophilicity of the PES membrane and increased the permeate flux. The anti-bacterial and anti-biofouling properties of the bio-Ag^{<font size="1">0</font>}/PES nanocomposites membrane were tested with pure cultures (<em>Escherichia coli</em> and <em>Pseudomonas aeruginosa</em>) and a mixed culture (an activated sludge bioreactor), respectively. The bio-Ag^{<font size="1">0</font>}/PES composite membranes, even with the lowest content of biogenic silver (140&nbsp;mg&nbsp;bio-Ag^{<font size="1">0</font>}&nbsp;m^{<font size="1">&minus;2</font>}), not only exhibited excellent anti-bacterial activity, but also prevented bacterial attachment to the membrane surface and decreased the biofilm formation during a 9 weeks test