Accurately measuring nanocarbon fluxes in complex systems such as soils remains a significant challenge in assessing the potential environmental fate of manufactured carbon nanomaterials (MCN). Stable isotope mass spectrometry (IRMS) allows for the quantification of processes affecting MCN such as microbially mediated oxidation in complex systems . This approach compliments methods that require extraction of nanomaterials from complex matrices and thus has significant utility in the laboratory when studying the environmental processes controlling the fate of nanomaterials in soils. As an example of a possible role for IRMS in nanometrology, we present results from an investigation on the coupled processes of photochemical transformation and subsequent microbial transformation of C60 fullerenes. To simulate photochemical weathering, aqueous suspensions of 5 atom% C60 fullerene were irradiated in a photo-reactor for 0, 10, 30, or 60 days before being added to soil microcosms. Similarly 13C-labelled C60 fullerols were included as controls corresponding to maximally oxidized fullerenes. The use of 13C-enriched nanomaterials allowed for the determination of the carbon source used in microbial respiration and MCN sequestration within the soil. Mineralization of MCN was greatest in microcosms containing labelled fullerols and least in microcosms receiving untreated fullerenes. Beyond these end members the relationships between the duration of the UV treatment and subsequent microbial interactions were dependent on soil type. MCN oxidation in the sandy, low carbon soil increased with photo-treatment time. Microbial community analysis by denaturing gradient gel electrophoresis found that communities in both soils were found to be significantly altered with the addition of untreated fullerenes. As was the case with MCN oxidation, the impacts of intermediately UV-treated fullerenes on microbial community were dependent on soil type; with sandy soil and clay rich soil more impacted by 60- and 10-day treated MCN respectively.

Measuring nanocarbon fluxes by tracing stable isotope labelled nanomaterials

249th National Meeting (2015)

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.