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

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-Ag0) were embedded in polyethersulfone (PES) membranes, using the phase-inversion method. The effects of the bio-Ag0 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-Ag0 incorporation slightly increased the hydrophilicity of the PES membrane and increased the permeate flux. The anti-bacterial and anti-biofouling properties of the bio-Ag0/PES nanocomposites membrane were tested with pure cultures (Escherichia coli and Pseudomonas aeruginosa) and a mixed culture (an activated sludge bioreactor), respectively. The bio-Ag0/PES composite membranes, even with the lowest content of biogenic silver (140 mg bio-Ag0 m−2), 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.

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► Bio-Ag0 increased the hydrophilicity and permeate flux.
► The bio-Ag0/PES membrane exhibited excellent anti-biofouling property.
► Silver loss was effectively prevented by bio-Ag0.
► Anti-biofouling effect lasted for long term.