Last data update: May 20, 2024. (Total: 46824 publications since 2009)
Records 1-2 (of 2 Records) |
Query Trace: Birch QT [original query] |
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Nano-enhanced treatment of per-fluorinated and poly-fluorinated alkyl substances (PFAS)
Birch QT , Birch ME , Nadagouda MN , Dionysiou DD . Curr Opin Chem Eng 2022 35 Per-fluorinated and poly-fluorinated alkyl substances (PFAS) are environmentally pervasive and persistent. They have been associated with adverse health effects and are a major public health concern. Water contamination is a highly challenging problem due to the large number of PFAS and the limitations of conventional treatments. Nanoscale technologies offer new approaches such as high-capacity, selective sorbents with rapid uptake and regeneration, and integrated methods that capture and destroy PFAS. Nano-enhanced materials can improve the kinetics and selectivity of PFAS uptake (physical removal) and destruction, and the treatment materials can potentially be reused/recycled. Nanoscale technologies also offer opportunities to improve the performance of most conventional treatments. Some recent nano-enhanced approaches for PFAS treatment of aqueous media are discussed in this paper. © 2021 Elsevier B.V. |
Quantification of carbon nanotubes by Raman analysis
Lynch JA , Birch QT , Ridgway TH , Birch ME . Ann Work Expo Health 2018 62 (5) 604-612 The increasing prevalence of carbon nanotubes (CNTs) in manufacturing and research environments, together with the potential exposure risks, necessitates development of reliable and accurate monitoring methods for these materials. We examined quantification of CNTs by two distinct methods based on Raman spectroscopy. First, as measured by the Raman peak intensity of aqueous CNT suspensions, and second, by Raman mapping of air filter surfaces onto which CNTs were collected as aerosols or applied as small-area (0.05 cm2) deposits. Correlation (R2 = 0.97) between CNT concentration and Raman scattering intensity for suspensions in cuvettes was found over a concentration range from about 2 to 10 microg/ml, but measurement variance precludes practical determination of a calibration curve. Raman mapping of aerosol sample filter surfaces shows correlation with CNT mass when the surface density is relatively high (R2 = 0.83 and 0.95 above about 5 microg total mass on filter), while heterogeneity of CNT deposition makes obtaining representative maps of lower density samples difficult. This difficulty can be mitigated by increasing the area mapped relative to the total sample area, improving both precision and the limit of detection (LOD). For small-area deposits, detection of low masses relevant to occupational monitoring can be achieved, with an estimated LOD of about 50 ng. |
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