Electrochemical Multiwalled Carbon Nanotube Filter for Viral and Bacterial Removal and Inactivation

Department of Chemical and Environmental Engineering, Yale University , New Haven, Connecticut 06520-8286, United States.
Environmental Science & Technology (Impact Factor: 5.33). 03/2011; 45(8):3672-9. DOI: 10.1021/es2000062
Source: PubMed


Nanotechnology has potential to offer solutions to problems facing the developing world. Here, we demonstrate the efficacy of an anodic multiwalled carbon nanotube (MWNT) microfilter toward the removal and inactivation of viruses (MS2) and bacteria (E. coli). In the absence of electrolysis, the MWNT filter is effective for complete removal of bacteria by sieving and multilog removal of viruses by depth-filtration. Concomitant electrolysis during filtration results in significantly increased inactivation of influent bacteria and viruses. At applied potentials of 2 and 3 V, the electrochemical MWNT filter reduced the number of bacteria and viruses in the effluent to below the limit of detection. Application of 2 and 3 V for 30 s postfiltration inactivated >75% of the sieved bacteria and >99.6% of the adsorbed viruses. Electrolyte concentration and composition had no correlation to electrochemical inactivation consistent with a direct oxidation mechanism at the MWNT filter surface. Potential dependent dye oxidation and E. coli morphological changes also support a direct oxidation mechanism. Advantages of the electrochemical MWNT filter for pathogen removal and inactivation and potential for point-of-use drinking water treatment are discussed.

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    • "For the coating strategy, the durability of the coated layer of conductive materials was normally questionable. Carbon nanotubes (CNTs), owing to their superior electrical conductivity and physicochemical stability, have drawn much attention as an ideal conductive material [26] [27] [28] [29] [30] [31] [32]. Polyvinylidene fluoride (PVDF), as one of the most extensively used membrane materials, is well known for its outstanding mechanical strength, chemical resistance, and thermal stability [33] [34] [35]. "
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    • "Therefore, FCV can be electrochemically inactivated without risk of producing DBPs. Using the proposed method, FCV may be oxidized via the electrode surface, as described previously [16] [17] [18]. Because the major capsid protein was not fragmented or degraded following electrochemical treatment (Fig. 3), the protein oxidation may contribute to FCV inactivation. "
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