Aquatic Biofouling Prevention by Electrically Charged Nanocomposite Polymer Thin Film Membranes

• Published in: Environmental science & technology 2013-03, Vol.47 (6), p.2760-2768
• Main Authors: de Lannoy, Charles-François, Jassby, David, Gloe, Katie, Gordon, Alexander D, Wiesner, Mark R
• Format: Article
• Language: English
• Subjects: Applied sciences; Biodeterioration. Biofouling; Biofilms; Biofilms - growth & development; Biofouling - prevention & control; Biological and medical sciences; Biotechnology; Chemical engineering; Conductivity; Electric Conductivity; Electrodes; Equipment Design; Exact sciences and technology; Filtration - instrumentation; Fundamental and applied biological sciences. Psychology; Industrial applications and implications. Economical aspects; Membrane separation (reverse osmosis, dialysis...); Membranes; Membranes, Artificial; Nanocomposites; Nanocomposites - chemistry; Nanotubes; Permeability; Polymers; Polymers - chemistry; Pseudomonas aeruginosa - growth & development; Thin films
• ISSN: 0013-936X; 1520-5851
• DOI: 10.1021/es3045168

Electrically conductive polymer-nanocomposite (ECPNC) tight nanofiltration (NF) thin film membranes were demonstrated to have biofilm-preventing capabilities under extreme bacteria and organic material loadings. A simple route to the creation and application of these polyamide-carbon nanotube thin films is also reported. These thin films were characterized with SEM and TEM as well as FTIR to demonstrate that the carbon nanotubes are embedded within the polyamide and form ester bonds with trimesoyl chloride, one of the monomers of polyamide. These polymer nanocomposite thin film materials boast high electrical conductivity (∼400 S/m), good NaCl rejection (>95%), and high water permeability. To demonstrate these membranes’ biofouling capabilities, we designed a cross-flow water filtration vessel with insulated electrical leads connecting the ECPNC membranes to an arbitrary waveform generator. In all experiments, conducted in highly bacterially contaminated LB media, flux tests were run until fluxes decreased by 45 ± 3% over initial flux. Biofilm-induced, nonreversible flux decline was observed in all control experiments and a cross-flow rinse with the feed solution failed to induce flux recovery. In contrast, flux decrease for the ECPNC membranes with an electric potential applied to their surface was only caused by deposition of bacteria rather than bacterial attachment, and flux was fully recoverable following a short rinse with the feed solution and no added cleaning agents. The prevention of biofilm formation on the ECPNC membranes was a long-term effect, did not decrease with use, and was highly reproducible.