Reaction of Water-Stable C 60 Aggregates with Ozone
School of Civil and Environmental Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332, USA. Environmental Science and Technology
(Impact Factor: 5.33).
12/2007; 41(21):7497-502. DOI: 10.1021/es0708058
While the reactivity of C60 has been described in a variety of organic solvents, little information is available regarding aqueous-based reactions due to solubility limitations. In this study, a reaction between C60, as a nanoscale suspension, and dissolved ozone in the aqueous phase was investigated. Findings indicate a facile reaction occurs, resulting in aggregate dissolution concurrent with formation of water-soluble fullerene oxide species. Product analyses, including 13C NMR, MS (LDI), FTIR, UV-Vis, and XPS, indicate highly oxidized fullerene with an average of approximately 29 oxygen additions per molecule, arranged in repeating hydroxyl and hemiketal functionalities. These findings are significant in that they (1) demonstrate the feasibility of other aqueous-based fullerene chemistries, including those for alternative synthesis routes, which might otherwise be considered prohibitive on the basis of solubility limitations, and (2) imply that the aqueous reactivity of fullerene-based materials must be considered appropriately for accurate assessment of their transport, fate, and potential risk(s) in environmental systems.
Available from: Xianji Tao
- "Therefore, the nC 60 in this research was prepared according to the method of THF (Fortner et al., 2005; Tao et al., 2009). The residual THF and its derivatives were removed 10 times by YM 20 000 membranes under nitrogen pressure (Fortner et al., 2007). Final residual organic concentrations in nC 60 stock solution were lower than the detection limit (<1 lg L À1 ) of a GC–MS (Agilent 6890/5793 GC/MS equipped with a HP-5MS (a 30 m Â 0.25 mm i.d. "
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ABSTRACT: Understanding sub-lethal effects of nanomaterial may be particularly important to determining ecosystem responses as current levels of nanomaterial release are low compared to levels projected for the future. In this work, the sub-lethal effects of water stable, nanocrystalline fullerenes as C60 (termed nC60) were studied on Scenedesmusobliquus, a globally distributed phytoplankton. Sub-lethal concentration for S. obliquus was firstly determined as 0.09mgL(-1) using the standard 72h exposure tests (OECD Guideline 201). Subsequent sub-lethal experiment of nC60 on the S. obliquus was carried out for 60d and focused on the photosynthesis processes. The results demonstrate that upon sub-lethal exposure, the photosynthetic products of polysaccharide, soluble protein and total lipid were decreased with exposure time. The photosynthetic pigments of chlorophyll a and chlorophyll b were negatively impacted. Further investigations indicate that the decrements in photosynthetic products and pigments were mainly due to the algal Mg(2+) decrement (by 40%) at the sub-lethal concentration (0.09mgL(-1)) of nC60. The decrement in Mg(2+) of S. obliquus was due to the inhibition of Mg(2+)-ATPase activity caused by nC60. Sum up, these results not only describe the sub-lethal effects but also provide the probably mechanism for sub-lethal effects of nC60 on exposed S. obliquus.
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- "roles of oxygen in C 60 photo-transformation. The reaction products of nC 60 under sunlight were suggested to be highly oxidized fullerenes with repeating hydroxyl and hemiketal functional groups (Fortner et al., 2007). Thus, C 60 chemical degradation by UV light was accomplished by an oxidative pathway. "
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ABSTRACT: The environmental application and risk assessment of manufactured nanoparticles (MNPs) in soil greatly depend on our understanding of the interactions between MNPs and soil components. Because of the complexity of the soil system and the very early stage of MNP research in soil, our understanding of MNP behaviour in this system is very limited. This review summarizes the progress of research on MNPs and their implications for soils. Manufactured nanoparticles are applied deliberately for soil remediation and are also released unintentionally through various other pathways to soil. Their colloidal behaviour in the soil system is discussed by analysing the effect of dissolved organic matter, light irradiation, water chemistry conditions and biological processes. The methods currently used for modelling MNP leaching and transport are summarized and several requirements for model improvement are proposed. The current topics regarding the environmental risks of MNPs (such as identifying the toxicity of MNPs and their dissolved ions, evidence that MNPs may be taken up by soil organisms or the risks of other pollutants as affected by the presence of MNPs) are described. Future research directions are discussed and proposed.
Available from: Alexander M. Puzrin
- "Fisher Scientific) saturated (ca. 10 mg/L) with C 60 with ultra-pure water (>18 MΩ/cm) at pH 5, which was added at rate of 500 mL/min into a vigorously stirred C 60 -THF solution (Deguchi et al., 2001;Fortner et al., 2005). After a triple distillation process, suspensions were further purified according toFortner et al. (2007), exchanging > 99% of the solvent (as water, including > 99% of all dissolved impurities including THF and/or THF derivatives) to ensure absolute minimal extraneous solute interferences and high sample purity. Solvent exchange was performed with a low-pressure (N 2 ) stir cell (Amicon, Millipore, USA) method using an ultrafiltration membrane (YM10, molecular weight cut-off = 10,000; Millipore, USA). "
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ABSTRACT: The research presented details specific interactions of underivatized C60 as an aggregate suspension in water (termed nC60) with clay minerals (montmorillonite and kaolinite), and a synthetic layered double hydroxide LDH. Batch and 1-D flow-through column interactions were analysed via UV/Vis spectroscopy, X-ray diffraction analysis, and transmission electron microscopy. Results indicate that nC60 suspended in water interacted with all the solid materials (‘clays’) studied. The LDH, with a net positive surface charge, has the greatest capacity to associate with the negatively charged nC60, capable of adsorbing 18% w/w. Column studies support sorption isotherm data, with LDH retarding nC60 transport >30 times more, in relative terms, than montmorillonite or kaolinite. Findings suggest that specific material interactions are primarily dominated by available surface area and electrostatic interaction at charged surfaces. Intercalation was not observed. These results have implications not only for understanding fullerene transport in the subsurface, but also towards engineering effective barriers for safe storage and disposal.
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