SWNT−MWNT Hybrid Filter Attains High Viral Removal and Bacterial Inactivation

Abstract

We describe the concept and demonstrate the efficacy of a novel SWNT-MWNT hybrid filter for the removal and inactivation of microbial pathogens from water. The filter is composed of a thin SWNT layer (0.05 mg cm(-2)) on top of a thicker MWNT layer (0.27 mg cm(-2)) supported by a microporous support membrane. The SWNT-MWNT filter exhibits high log removal of several model viruses (MS2, PRD1, and T4 bacteriophages) by depth filtration, which predominantly takes place in the thicker and more uniform MWNT layer. The filter removes all bacteria by a sieving mechanism, with the top SWNT layer providing high levels of inactivation of model bacteria (Escherichia coli K12 and Staphylococcus epidermidis), as well as microbes from river water and treated wastewater effluent. The dual-layer SWNT-MWNT filter lays the framework for new possibilities in point-of-use water filtration.

Carbon nanotube-based antimicrobial biomaterials formed via layer-by-layer assembly with polypeptides

“…The antimicrobial nature of carbon nanotubes has received considerable attention in the last few years, with applications including water-filters, bio-fouling resistant membranes, and surface coatings [9,11,[71][72][73][74][75]. The SWNT antimicrobial mechanism is thought to involve a combination of cell membrane damage and oxidative stress [76] [12], and metallic (as opposed to semiconducting) nanotubes are thought to be more toxic [13].…”

Bioaerosol Science, Technology, and Engineering: Past, Present, and Future

“…In recent years, antimicrobial materials are also incorporated into air filter to inhibit the growth of collected microorganisms (Foarde et al 2000;Cecchini et al 2004;Lee et al 2008a). The filtration technologies developed using nanoscale materials for water treatments (Brady-Estevez et al 2010;Schoen et al 2010) can certainly be adapted for airborne microbial aerosol control. In a recent study, carbon nanotubebased filters were applied to controlling bioaerosols, and the results indicated that a physical removal efficiency of 95% was obtained for B. subtilis var niger at a carbon nanotube loading of 1.6 µg/cm 2 (Guan and Yao 2010).…”

“…In a recent study, carbon nanotubebased filters were applied to controlling bioaerosols, and the results indicated that a physical removal efficiency of 95% was obtained for B. subtilis var niger at a carbon nanotube loading of 1.6 µg/cm 2 (Guan and Yao 2010). Studies indicated that carbon nanotube exhibited strong toxicity toward Escherichia coli (Kang et al 2009;Brady-Estevez et al 2010). In another study, carbon nanotube-made filter was shown to be capable of both collecting and inactivating airborne microbial species (Xu and Yao 2011).…”

Effects of single-walled carbon nanotube filter on culturability and diversity of environmental bioaerosols

“…(Brady-Esté vez et al, 2008); therefore by linear extrapolation the SWNT depth here could be up to 4 mm at high loading (0.64 mg/cm 2 ). In a previous study, it was shown that addition of SWNT would result in modest reduction of permeability (Brady-Esté vez, Schnoor, Kang, & Elimelech, 2010). Here, we used a filter with pore size of 0.45 um.…”