Abstract

Increasing production and use of carbonaceous nanomaterials (NMs) will increase their release to the sewer system and to municipal wastewater treatment plants. There is little quantitative knowledge on the removal of multi-walled carbon nanotubes (MWCNTs), graphene oxide (GO), or few-layer graphene (FLG) from wastewater into the wastewater biomass. As such, we investigated the quantification of GO and MWCNTs by UV-Vis spectrophotometry, and FLG using programmable thermal analysis (PTA), respectively. We further explored the removal of pristine and oxidized MWCNTs (OMWCNTs), GO, and FLG in a biomass suspension. At least 96% of pristine and O-MWCNTs were removed from the water phase through aggregation and 30-min settling in presence or absence of biomass with an initial MWCNT concentration of 25 mg∙L–1. Only 65% of GO was removed with biomass concentration at or above 1,000 mg∙L–1 as total suspended solids (TSS) with the initial GO concentration of 25 mg∙L–1. As UV-Vis spectrophotometry does not work well on quantification of FLG, we studied the removal of FLG at a lower biomass concentration (50 mg TSS∙L–1) using PTA, which showed a 16% removal of FLG with an initial concentration of 1 mg∙L–1. The removal data for GO and FLG were fitted using the Freundlich equation (R2 = 0.55, 0.94, respectively). The data presented in this study for carbonaceous NM removal from wastewater provides quantitative information for environmental exposure modeling and life cycle assessment.

Original languageEnglish (US)
Pages (from-to)823-831
Number of pages9
JournalFrontiers of Environmental Science and Engineering
Volume9
Issue number5
DOIs
StatePublished - Apr 24 2015

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Keywords

  • graphene
  • graphene oxide
  • multi-walled carbon nanotubes
  • removal
  • wastewater biomass

ASJC Scopus subject areas

  • Environmental Science(all)

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