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Fate of radiolabeled C60 fullerenes in aged soils
2016
Navarro, Divina A. | Kookana, Rai S. | McLaughlin, Mike J. | Kirby, Jason K.
Fullerenes (e.g. C60, C70, etc.) present in soil may undergo changes in its retention with aging. In this study, the partitioning behavior of (14C)-C60 aged up to 12 weeks was investigated in biosolids-amended soil. Spiked samples were subjected to sequential partitioning using water, methanol, and toluene followed by total combustion of solids; the distribution of 14C across solvents and matrices were used to provide insights on C60 behavior. In most samples, 14C only partitioned in toluene with the remaining (non-extractable) activity detected in the solid phase. In all biosolids-amended soil samples, an increase in non-extractable 14C were observed for those exposed to light (vs dark) with the greatest difference observed in biosolids + sand samples. Possible processes that contribute to the observed 14C distribution, i.e. retention and potential transformation of C60, were discussed. Over-all, results suggest that environmental exposure to C60 and potentially transformed C60 species, as a result of their release from soils, is likely to be low.
Afficher plus [+] Moins [-]Novel green PVA-fullerenol mixed matrix supported membranes for separating water-THF mixtures by pervaporation
2018
Penkova, Anastasia V. | Dmitrenko, Maria E. | Ermakov, Sergey S. | Toikka, Alexander M. | Roizard, Denis
This study focuses first on the preparation of mixed matrix supported membranes of polyvinyl alcohol (PVA) and low-hydroxylated fullerenol C₆₀(OH)₁₂ used to create water selective membranes and then on their pervaporation properties for the separation of water-THF mixtures. These novel supported PVA membranes containing nano-carbon particles were prepared to reach high membrane performance for further integration in a dehydration process, such as distillation coupled to pervaporation. The separation of water-THF mixtures was performed with the supported membranes over a wide range of water concentrations in the feed mixture, i.e., from the azeotrope range up to 30 wt%, to evaluate the performance and stability of the thin active layer. SEM was used to visualize the internal morphology of the membrane. The influence of temperature on the transport properties was also investigated. All the membranes were highly water selective and stable up to 30 wt% water in the feed. The best compromise of transport properties was obtained for the C₆₀(OH)₁₂(5%)-PVA supported composite membrane: a permeate enrichment of 99.3 ± 0.3 wt% water and a flux of 0.25 ± 0.02 kg/(m² h) for the separation of a mixture containing 5.7 wt% water and 94.3 wt% tetrahydrofuran (THF) at 30 °C. Considering its water stability, this supported membrane with a dense layer thinner than 2 μm appears promising for use in hybrid industrial processes to upgrade solvents with a smaller environmental footprint than conventional methods.
Afficher plus [+] Moins [-]Developmental toxicity of carbon nanoparticles during embryogenesis in chicken
2020
Samak, Dalia H. | El-Sayed, Yasser S. | Shaheen, Hazem M. | El-Far, Ali H. | Abd El-Hack, Mohamed E. | Noreldin, Ahmed E. | El-Naggar, Karima | Abdelnour, Sameh A. | Saied, Essa M. | El-Seedi, Hesham R. | Aleya, Lotfi | Abdel-Daim, Mohamed M.
Nanoparticles (NPs) are very small particles present in a wide range of materials. There is a dearth of knowledge regarding their potential secondary effects on the health of living organisms and the environment. Increasing research attention, however, has been directed toward determining the effects on humans exposed to NPs in the environment. Although the majority of studies focus on adult animals or populations, embryos of various species are considered more susceptible to environmental effects and pollutants. Hence, research studies dealing mainly with the impacts of NPs on embryogenesis have emerged recently, as this has become a major concern. Chicken embryos occupy a special place among animal models used in toxicity and developmental investigations and have also contributed significantly to the fields of genetics, virology, immunology, cell biology, and cancer. Their rapid development and easy accessibility for experimental observance and manipulation are just a few of the advantages that have made them the vertebrate model of choice for more than two millennia. The early stages of chicken embryogenesis, which are characterized by rapid embryonic growth, provide a sensitive model for studying the possible toxic effects on organ development, body weight, and oxidative stress. The objective of this review was to evaluate the toxicity of various types of carbon black nanomaterials administered at the beginning of embryogenesis in a chicken embryo model. In addition, the effects of diamond and graphene NPs and carbon nanotubes are reviewed.
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