Carbon Nanotube Selective Membranes with Subnanometer, Vertically Aligned Pores, and Enhanced Gas Transport Properties

Membranes consisting of ultrathin, oriented, single-wall carbon nanotube (SWCNT) micropores with a diameter of ∼4 Å were developed. c-Oriented AFI-type aluminophosphate (AlPO) films (AlPO4-5 and CoAPO-5), consisting of parallel channels 7.3 Å in diameter, were first fabricated by seeded growth on macroporous alumina supports, and used as templates for synthesis of CNTs inside the zeolitic channels by thermal treatment, utilizing the structure directing agent (amine) occluded in the channels as carbon source. Incorporation of CNTs inside the AFI channels altered the transport mechanism of all permeating gases tested, and imposed a substantial increase in their permeation rates, in comparison to the AlPO4-5 membrane, despite the pore size reduction due to nanotube growth. The enhancement of the permeation rates is attributed to repulsive potentials between gas molecules and occluded nanotubes, which limit adsorption strength and enhance diffusivity, coupled to the smooth SWCNT surface that enables fast diffusion through the nanotube interior. Separation ability, evaluated with respect to H2 and CO2 gases, was enhanced by using polysterene as defect-blocking medium on both AlPO and CNT/AlPO membranes and was preserved after CNT growth. © 2015 American Chemical Society

Persistent and emerging pollutants assessment on aquaculture oysters (Crassostrea gigas) from NW Portuguese coast (Ria De Aveiro)

The study aim was to determine a range of relevant persistent and emerging pollutants in oysters produced in an aquaculture facility located in an important production area, to assure their safety for human consumption. Pollutants, including 16 PAHs, 3 butyltins (BTs), 29 flame retardants (FRs, including organophosphate and halogenated FRs), 35 pesticides (including 9 pyrethroid insecticides) and 13 personal care products (PCPs, including musks and UV filters), were determined in oysters' tissues collected during one year in four seasonal sampling surveys. The seasonal environmental pollution on the production site was evaluated by water and sediment analysis. Furthermore, oysters' nutritional quality was also assessed and related with the consumption of healthy seafood, showing that oysters are a rich source of protein with low fat content and with a high quality index all year around. Results showed that most analysed pollutants were not detected either in oyster tissues or in environmental matrixes (water and sediments). The few pollutants detected in oyster tissues, including both regulated and non-legislated pollutants, such as a few PAHs (fluorene, phenanthrene, anthracene, fluoranthene, pyrene and indenopyrene), FRs (TPPO, TDCPP, DCP, BDE-47, BDE-209 and Dec 602) and PCPs (galaxolide, galaxolidone, homosalate and octocrylene), were present at low levels (in the ng/g dw range) and did not represent a significant health risk to humans. The observed seasonal variations related to human activities (e.g. tourism in summer) highlights the need for environmental protection and sustainable resource exploration for safe seafood production. © 2019 Elsevier B.V.This work was supported by the Structured R&D&I Project INNOVMAR – “Innovation and Sustainability in the Management and Exploitation of Marine Resources” (ref. NORTE-01-0145-FEDER-000035) within the research line “INSEAFOOD - Innovation and valorization of seafood products: meeting local challenges and opportunities”, founded by the Northern Regional Operational Programme (NORTE2020) through the European Regional Development Fund (ERDF). This study was also supported by the SEA-on-a-CHIP project, funded from European Union Seventh Framework Programme (FP7-OCEAN-2013) under grant agreement No. 614168. This work has been also financially supported by the Generalitat de Catalunya (Consolidated Research Group 2017 SGR 01404 – Water and Soil Quality Unit). Biotage is acknowledged for providing SPE cartridges. Authors acknowledge Carlos R. Gomes for helping on multivariated analysis.Peer reviewe