106 research outputs found

    Electrodialytic hydrogen production and critical raw materials recovery from secondary resources

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    FCT/MCTES through grant UIDB/04085/2020. J. Almeida acknowledges Funda√ß√£o para a Ci√™ncia e a Tecnologia and EcoCoRe Doctoral program for her PhD fellowship PD\BD\135170\2017.Electrodialytic technologies are defined as treatment processes that promote the removal/recovery of substances in a matrix, based on the application of low-level current intensities. Additionally, along these processes hydrogen is self-generated, allowing them to operationally produce clean energy. This energy carrier is produced due to electrolysis reactions occurring at the cathode end of the electrodialytic reactor, when using inert electrodes. Herein, hydrogen production during the electrodialytic treatment of sewage sludge and mining residues suspensions (coupled with effluent or sewage sludge), at 50 and 100 mA, was assessed. During the electrodialytic treatment of sewage sludge, hydrogen purity production achieved 33%. When effluent or sewage sludge were used as enhancements in mining residues suspensions, hydrogen purity reached 71% and 34%, respectively. Furthermore, a proton-exchange membrane fuel cell was connected to the cathode compartment of the electrodialytic reactor. The electrical energy generated from self-hydrogen produced at 100 mA achieved ‚Čą1 V in all performed experiments. Simultaneously, critical raw materials extraction, namely phosphorus and tungsten, was evaluated. When the process was applied to mining residue suspensions combined with sewage sludge, the highest extraction ratio of phosphorus (71%) and tungsten (62%) was observed.publishersversionpublishe

    Life Cycle Assessment of Electrodialytic Technologies to Recover Raw Materials from Mine Tailings

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    UIDB/04085/2020 PD/BD/135170/2017Currently, the development of new sustainable technologies to recover raw materials from secondary resources has shown a lack of available data on the processes and supplies involved, as well as their environmental impacts. The present research has conducted a life cycle assessment of electrodialytic (ED) technologies to improve critical raw materials recovery in the Portuguese mining industry. To critically appraise the activities from the mining sector and gather data on technical and environmental issues, three waste management scenarios were considered: (1) ED treatment with a deep eutectic solvent as an adjuvant; (2) ED treatment with simultaneous H2 recovery; and (3) ED treatment with sodium chloride as an enhancement. The data presented were based on global databases, technical reports from official sources, and peer-reviewed published experimental outcomes. The estimated results indicated that one of the constraints in applying ED technologies is energy consumption and thus the impacts are highly dependent on energy source choices. On the other hand, as a consequence of the H2 inherently produced by ED technologies, there is a direct potential for energy recovery. Therefore, considering an upscale approach of the ED reactor based on bench scale experimental results, the H2 could be reused in the ED facility or stored. Additionally, according to experimental data, 22% of the tungsten from the fine mine tailings could be recovered. Finally, the possibility to remove 63% of arsenic from mine tailings could decrease contamination risks while creating additional marketable co-products.publishersversionpublishe

    The chemical ecology of Harmonia axyridis

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    peer reviewedIn the recent SI of BioControl and resultant book from this working group (Roy et al., 2012), we contributed a review paper on the chemical ecology of the invasive aphidophagous ladybird Harmonia axyridis (Sloggett et al., 2011). This paper focused on both the pure and applied aspects of this subject, including sections on: (1) chemical defence; (2) foods, feeding and reproduction; (3) H. axyridis chemistry, humans and human activity, and (4) future research perspective

    First report of fatty acid-derived alkaloids produced by species of the ladybird genus Scymnus (Coccinellidae: Coleoptera)

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    ABSTRACT: Species in the genus Scymnus Kugelann are common, but there is little information available on their defence compounds. Pupae are covered with setae on tips of which there are small droplets of liquid. This study explored the patterns of the distribution of the droplets and the influence of diet on their production in five species of Scymnus. GC-MS analyses were used to determine the chemical identity of droplets. All these species produced droplets, but the patterns in the distributions varied among species. Preliminary data indicates a de novo synthesis of the droplet compounds by these ladybirds. The results of the GC-MS analyses suggest that Scymnus spp. produce azamacrolides, which are fatty acid-derived alkaloids.info:eu-repo/semantics/publishedVersio

    Electronic tongue coupled to an electrochemical flow reactor for emerging organic contaminants real time monitoring

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    UID/AMB/04085/2019. UID/FIS/00068/2019. PTDC/FIS-NAN/0909/2014. SFRH/BD/114674/2016.Triclosan, which is a bacteriostatic used in household items, has raised health concerns, because it might lead to antimicrobial resistance and endocrine disorders in organisms. The detection, identification, and monitoring of triclosan and its by-products (methyl triclosan, 2,4-Dichlorophenol and 2,4,6-Trichlorophenol) are a growing need in order to update current water treatments and enable the continuous supervision of the contamination plume. This work presents a customized electronic tongue prototype coupled to an electrochemical flow reactor, which aims to access the monitoring of triclosan and its derivative by-products in a real secondary effluent. An electronic tongue device, based on impedance measurements and polyethylenimine/poly(sodium 4-styrenesulfonate) layer-by-layer and TiO2, ZnO and TiO2/ZnO sputtering thin films, was developed and tested to track analyte degradation and allow for analyte detection and semiquantification. A degradation pathway trend was observable by means of principal component analysis, being the sample separation, according to sampling time, explained by 77% the total variance in the first two components. A semi-quantitative electronic tongue was attained for triclosan and methyl-triclosan. For 2,4-Dichlorophenol and 2,4,6-Trichlorophenol, the best results were achieved with only a single sensor. Finally, working as multi-analyte quantification devices, the electronic tongues could provide information regarding the degradation kinetic and concentrations ranges in a dynamic removal treatment.publishersversionpublishe

    Polyelectrolyte based sensors as key to achieve quantitative electronic tongues: Detection of triclosan on aqueous environmental matrices

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    This work was supported by the Project ‚ÄúDevelopment of Nanostructures for Detection of Triclosan Traces on Aquatic Environments‚ÄĚ (PTDC/FIS-NAN/0909/2014). The Center for Environmental and Sustainability Research CENSE and Centre of Physics and Technological Research CEFITEC,which is Ô¨Ānanced bynational funds from FCT/MEC (UID/AMB/04085/2019 and UID/FIS/00068/2019). This research was anchored by the RESOLUTION LAB, an infrastructure at NOVA School of Science and Technology. J. Pereira-da-Silva and P. Zagalo acknowledge their fellowships PD/BD/142768/2018, PD/BD/142767/2018 from RABBIT Doctoral Program, respectively. C. Magro acknowledges to Funda√ß√£o para a Ci√™ncia e a Tecnologia for her PhD fellowship (SFRH/BD/114674/2016).Triclosan (TCS) is a bacteriostatic used in household items that promotes antimicrobial resistance and endocrine disruption effects both to humans and biota, raising health concerns. In this sense, new devices for its continuous monitoring in complex matrices are needed. In this work, sensors, based on polyelectrolyte layer-by-layer (LbL) films prepared onto gold interdigitated electrodes (IDE), were studied. An electronic tongue array, composed of (polyethyleneimine (PEI)/polysodium 4-styrenesulfonate (PSS))5 and (poly(allylamine hydrochloride/graphene oxide)5 LbL films together with gold IDE without coating were used to detect TCS concentrations (10‚ąí15‚Äď10‚ąí5 M). Electrical impedance spectroscopy was used as means of transduction and the obtained data was analyzed by principal component analysis (PCA). The electronic tongue was tested in deionized water, mineral water and wastewater matrices showing its ability to (1) distinguish between TCS doped and non-doped solutions and (2) sort out the TCS range of concentrations. Regarding film stability, strong polyelectrolytes, as (PEI/PSS)n, presented more firmness and no significant desorption when immersed in wastewater. Finally, the PCA data of gold IDE and (PEI/PSS)5 sensors, for the mineral water and wastewater matrices, respectively, showed the ability to distinguish both matrices. A sensitivity value of 0.19 ¬Ī 0.02 per decade to TCS concentration and a resolution of 0.13 pM were found through the PCA second principal component.publishersversionpublishe

    An annotated checklist of ladybeetle species (Coleoptera, Coccinellidae) of Portugal, including the Azores and Madeira Archipelagos

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    Research ArticleA comprehensive annotated checklist of the ladybeetle species of Portugal, including the Azores and Madeira archipelagos, is presented. The Coccinellidae fauna comprises a total of 101 species: 83 from the Mainland, 39 from Madeira, and 32 from the Azores. The listed species are distributed among 2 sub-families and 13 tribes: within the subfamily Microweiseinae, Madeirodulini (1 species), Serangiini (2 species), and within the subfamily Coccinellinae, Azyini (1 species), Chilocorini (4 species), Coccidulini (7 species), Coccinellini (30 species), Epilachnini (4 species), Hyperaspidini (7 species), Noviini (2 species), Platynaspini (1 species), Scymnini (37 species), Stethorini (3 species), and Sticholotidini (2 species). The Portuguese fauna comprises 10 exotic species: 5 present in the Mainland, 7 in Madeira, and 6 in the Azores. Harmonia axyridis (Pallas, 1773) from Madeira, Propylea quatuordecimpunctata (Linnaeus, 1758) from the Azores, Delphastus catalinae (Horn, 1895) from the Azores and Madeira, Nephus (Geminosipho) reunioni (F√ľrsch, 1974) and Nephus (Nephus) voeltzkowi Weise, 1910 from Madeira and Microserangium sp. from the Mainland, are reported for the first time. Some species are considered doubtful records, as explained in the text. These results were obtained by compiling information on the available literature regarding ladybeetle species on the Portuguese mainland and insular territories, and original datainfo:eu-repo/semantics/publishedVersio
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