Impact of solution chemistry on viral removal by a single-walled carbon nanotube filter

Anna S. Brady-Estévez, Thanh H. Nguyen, Leonardo Gutierrez, Menachem Elimelech

Research output: Contribution to journalArticle

Abstract

This study investigates the effectiveness of a single-walled carbon nanotube (SWNT) filter for removal of viruses from water. MS2 bacteriophage viral removal was examined over a range of environmentally relevant solution chemistries, spanning various ionic strengths, monovalent and divalent salts, pH, and natural organic matter (NOM) concentrations. Viral removal by the SWNT filter was governed by physicochemical (depth) filtration. The removal of viruses increased at higher ionic strengths (NaCl) due to suppression of repulsive electrostatic interactions between viruses and SWNTs. Addition of divalent salts, however, had varying impacts. While CaCl2 increased virus removal, likely due to complexation of calcium ions to viral surfaces, addition of MgCl2 reduced viral removal by the SWNT filter. Solution pH also had significant impact on viral removal as the interactions between viral particles and SWNTs changed from attractive below the virus isoelectric point (about pH 3.9) to repulsive at higher pH. Suwannee River NOM was shown to be detrimental to filter viral removal. Reduction of viral removal by NOM was attributed to adsorption of NOM macromolecules to viruses and SWNTs, thereby resulting in steric repulsive forces. Modifications of the filter to incorporate thicker SWNT layers mitigate the negative impacts of NOM on filter performance. This study has shown that while it is possible to attain high levels of viral removal over a broad range of solution chemistries, the extent of viral removal will be highly dependent on the specific solution chemistry of the treated water.

Original languageEnglish (US)
Pages (from-to)3773-3780
Number of pages8
JournalWater Research
Volume44
Issue number13
DOIs
StatePublished - Jul 2010

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Keywords

  • Carbon nanotubes
  • Filter
  • Pathogens
  • Solution chemistry
  • Virus removal

ASJC Scopus subject areas

  • Ecological Modeling
  • Water Science and Technology
  • Waste Management and Disposal
  • Pollution

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