Improved antibacterial activity of nanofiltration polysulfone membranes modified with silver nanoparticles

• Published in: Water research (Oxford) Vol. 81; pp. 333 - 342
• Main Authors: Andrade, Patricia Fernanda, de Faria, Andreia Fonseca, Oliveira, Silvana Ruella, Arruda, Marco Aurélio Zezzi, Gonçalves, Maria do Carmo
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 15-09-2015
• Subjects: Antibacterial activity; Antiinfectives and antibacterials; Biofilms - drug effects; Biofouling - prevention & control; Dispersion; Escherichia coli - growth & development; In situ leaching; Membranes; Membranes, Artificial; Metal Nanoparticles - chemistry; Morphology; Nanocomposite membranes; Nanocomposites - chemistry; Nanoparticles; Polymers - chemistry; Polysulfone membranes; Polysulfone resins; Silver; Silver - chemistry; Silver nanoparticles; Sulfones - chemistry; Antibacterial activity; Nanocomposite membranes; Polysulfone membranes; Silver nanoparticles
• ISSN: 0043-1354; 1879-2448
• DOI: 10.1016/j.watres.2015.05.006

Polysulfone membranes (PSf) containing silver nanoparticles were prepared by the wet phase-inversion process. Silver nanoparticles (AgNP) were dispersed into the polymer matrix using two different methodologies. In the first one, the AgNP were synthesized and further dispersed into the polymer solution (ex situ process). In the second method, the formation of the AgNP was performed in situ. The AgNP crystalline structure in the PSf membranes was confirmed by X-ray diffraction. Field emission scanning electron microscopy images showed that the addition of AgNP in PSf membranes caused no significant changes to the finger-like morphology. When the ex situ methodology was applied, 45 nm average size AgNP were uniformly distributed in the internal pores of the membranes. However, when the AgNP were formed through the in situ process, the AgNP were uniformly and preferentially distributed on the top and bottom surfaces of the membrane. In the last case, the AgNP showed cubic morphology when present in the bottom and top surfaces, however, when inside the membrane their morphology was spherical. The cubic-like nanoparticles displayed a 38 nm average edge length. The silver ion released from the membrane during water filtration was measured using inductively coupled plasma mass spectrometry, which showed a silver leaching of approximately 2 μg L−1. The nanocomposite membranes prepared by the in situ method exhibited a better antibacterial activity, in comparison to those prepared by ex situ, and also a decrease in 90% Escherichia coli adhered cells compared to the pristine PSf membranes. In conclusion, the in situ procedure can be considered a feasible, simple, and reproducible methodology to prepare anti-biofouling polysulfone membranes containing AgNP.
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•Polysulfone membranes with AgNP: the influence of in situ and ex situ methods.•AgNP shape and distribution in the polymer matrix are dependent on the preparation methodology.•In situ formation of the silver nanoparticles resulted in antibacterial membranes.•Potential application as nanofiltration membranes for wastewater treatment.