886 research outputs found

    Tailoring carbon nanotubes to enhance their efficiency as electron shuttle on the biological removal of acid orange 10 under anaerobic conditions

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    Anaerobic treatments have been described for the biodegradation of pollutants. However, the reactions proceed slowly due to the recalcitrant nature of these compounds. Carbon nanomaterials (CNM) intermediate in, and favor, the electron transfer, accelerating the anaerobic reduction of pollutants, which act as final electron acceptors. In the present work, different carbon nanotubes (CNT) with modified surface chemistry, namely CNT oxidized with HNO3 (CNT_HNO3) and CNT doped with nitrogen in a ball milling process (CNT_N_MB) were prepared using commercial CNT as a starting material. The new CNM were tested as redox mediators (RM), 0.1 g L−1, in the biological reduction of the azo dye, Acid Orange 10 (AO10), with an anaerobic granular sludge, over 48 h of reaction. Methane production was also assessed to verify the microorganism’s activity and the CNM’s effect on the methanogenic activity. An improvement in the biological removal of AO10 occurred with all CNM (above 90%), when compared with the control without CNM (only 32.4 ± 0.3%). The best results were obtained with CNT_N_MB, which achieved 98.2 ± 0.1% biological AO10 removal, and an 11-fold reduction rate increase. In order to confer magnetic properties to the CNM, tailored CNT were impregnated with 2% of iron-samples: CNTThis study was supported by the Portuguese Foundation for Science and Technology (FCT) under the scope of the strategic funding of UID/BIO/04469/2019 unit and BioTecNorte operation (NORTE‐01‐0145‐ FEDER‐000004) funded by the European Regional Development Fund under the scope of Norte2020 ‐ Programa Operacional Regional do Norte, as well as FCT/MCTES trough national funds (PIDDAC) and Base Funding – UIDB/50020/20 of the Associate Laboratory LSRE‐LCM – funded by national funds rough FCT/MCTES (PIDDAC). Ana Rita Silva holds a Grant from FCT, reference SFRH/BD/131905/2017. Salomé. G.P. Soares acknowledges FCT funding under the Scientific Employment Stimulus ‐ Institutional Call CEECINST/00049/2018.info:eu-repo/semantics/publishedVersio

    Assessment of ciprofloxacin photocatalysis by-products toxicity with Vibrio fischeri

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    The presence of pharmaceuticals in water has become a large concern due to the potential negative effects on humans and aquatic ecosystems. From these pharmaceuticals, antibiotics represent a serious problem since their overuse and misuse may lead to adverse environmental effects, in particular, toxicity to microflora and fauna and potential negative effects to humans [1]. Photocatalysis has become attractive to promote the degradation of contaminants in the aquatic environment since it allows their rapid and efficient removal from water, transforming them into by-products [2]. In order to evaluate toxicity of these by-products, several bio tests using bacteria (Vibrio fischeri) and algae (Daphnia spp.), among others, have been used [3]. In the present work a photocatalytic systems using commercial TiO2 and ZnO nanoparticles in suspension was used to degrade ciprofloxacin under UV radiation. Samples were withdraw over time in order to monitor degradation and toxicity. The luminescence of the bacteria Vibrio fischeri was used to test the toxicity of ciprofloxacin intermediate compounds, produced during the photocatalysis process. If a substance is toxic towards these bacteria, their normal luminescence decreases, as a consequence of a decreasing bacteria viability. Results (Figure 1) indicate that samples without ciprofloxacin degradation (t=0), in contact with bacteria (for 35 min), result in a higher luminescence than with completely degraded ciprofloxacin (t=15min). These results indicate that by products are responsible for low bacteria viability.FEDER through the COMPETE Program and by the Portuguese Foundation for Science and Technology (FCT) in the framework of the Strategic Project PEST-C/FIS/UI607/2011 and project PTDC/CTM-NAN/121038/2010

    Experimental characterization of gypsum-cork composite material reinforced with textile fibers

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    The study presented herein focus on the analysis of a series of experimental tests aiming at characterizing the performance of distinct textile fibers acting as a reinforcement of a gypsum-cork composite material. Two groups of textile fibers were selected, namely synthetic fibers (glass, recycled textile, acrylic and basalt) and natural fibers (banana and sisal). The reinforced composite material was assessed taking into account the mode I fracture energy by considering indirect tests on notched beams. Additionally, this material was submitted to distinct types of loading, namely uniaxial compression, from which it was possible to obtain the compressive strength and to calculate the elastic modulus, and flexural loading

    Bioinvasion in a Brazilian Bay: Filling Gaps in the Knowledge of Southwestern Atlantic Biota

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    Biological invasions are a major cause of global species change. Nevertheless, knowledge about the distribution and ecology of introduced species is regionally biased, and many gaps in knowledge exist for most developing countries.To study the zoobenthos on the hard substratum of the Ilha Grande Bay, a survey was conducted on both natural and artificial substrata at three depths and seven sites. The species recorded were classified as native, cryptogenic or introduced. Multivariate analyses were conducted to assess the prevalence of introduced species in these communities and to compare the distribution of species on natural and artificial substrata of this bay to identify possible discrepancies in habitat use. Of the 61 species, 25 were cryptogenic, 10 were introduced and 26 were native. Similar numbers of introduced species were found on both natural and artificial substrata, though the community composition was significantly different between them. We also compared the species composition of the Ilha Grande Bay survey to other inventories taken around the world. The highest similarities were found between the Ilha Grande Bay inventory and the Atlantic coastal region (Tampa Bay, USA and the Gulf of Mexico), American Samoa and Pearl Harbor (USA) inventories.This study presents the first published comprehensive list of hard substratum sessile marine invertebrate species in a Brazilian bay. The high percentage of cryptogenic species reveals gaps in both zoological records and information on introduced species for the Brazilian coast. The introduced species successfully colonized different sites in the Ilha Grande Bay, including both natural and artificial substrata. In addition, we find that artificial structures may not be good surrogates for natural rocky shores and may represent an ecological threat. Comparisons with other inventories suggest a history of broad-scale invasion, though more evidence is needed to support this conclusion

    Ciprofloxacin removal catalysed by conductive carbon materials

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    Current wastewater treatment technologies are not effective in the removal of pharmaceuticals. In anaerobic bioreactors, the electrons produced during the oxidation of organic matter can potentially be used for the biological reduction of pharmaceuticals. However, these reactions occur generally at a slow rate, due to electron transfer limitations, and might be accelerated through redox mediators (RM). Carbon nanomaterials (CM) have been effective RM in the biological reduction of other pollutants. For instance, CNT@2%Fe were found to increase 76-fold the biological reduction of Acid Orange 10. The magnetic properties of those composites allow their easier recover after the process by using a magnetic field. In this study, CNT and CNT@2%Fe were studied in the anaerobic removal of Ciprofloxacin (CIP). Furthermore, the potential contribution of adsorption and biodegradation processes for CIP removal was assessed. Toxicity assessment is highly important as it is desired that the products formed after the process are not more toxic than the initial compound. Moreover, the evaluation of the possible contribution of nanomaterials used in the process for the final toxic effect of threated solution, is crucial. In this sense, the detoxification of the treated solutions was evaluated towards Vibrio fischeri.This study was supported by the Portuguese Foundation for Science and Technology (FCT) under the scope of the strategic funding of UID/BIO/04469/2019 unit and BioTecNorte operation (NORTE-01-0145-FEDER-000004) funded by the European Regional Development Fund under the scope of Norte2020 - Programa Operacional Regional do Norte.info:eu-repo/semantics/publishedVersio

    TiO2/graphene and TiO2/graphene oxide nanocomposites for photocatalytic applications: A computer modeling and experimental study

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    Supplementary data related to this article can be found at http://dx. doi.org/10.1016/j.compositesb.2018.03.015.This work reports a computational study, focused on graphene (G) and graphene oxide (GO) interfaces with titanium dioxide (TiO2), and an experimental assay on the photocatalytic activity of TiO2/G and TiO2/GO nanocomposites in the degradation of two different pollutants: methylene blue and ciprofloxacin. Both carbon nanostructures were compared due to their different chemical structure: GO is a G derivative with oxygen functional groups which should promote a closer chemical interaction with TiO2 nanoparticles. Computational models of the fundamental properties of the composites indicated potentially improved photocatalytic activity compared to TiO2, namely lower band gaps and charge carrier segregation at the interfaces. These fundamental properties match qualitatively experimental results on methylene blue, which was more effectively degraded by TiO2/G and TiO2/GO nanocomposites than by pure TiO2 under UV light. In contrast, the same nanocomposites were found to be less efficient to degrade ciprofloxacin than pure TiO2 under visible and UV light. Therefore, this work showcases the relevance of an efficient matching between the catalyst and the molecular properties and structure of the pollutant.This work was supported by the Portuguese Foundation for Science and Technology (FCT) in the framework of the Strategic Project PESTC/FIS/UI607/2014 and PEST-C/QUI/UIO686/2014 and the CICECO Aveiro Institute of Materials, POCI-01-0145-FEDER-007679 (FCT ref. UID/CTM/50011/2013). Access to computing facilities provided by the Project “Search-ON2: Revitalization of HPC infrastructure of UMinho” (NORTE-07-0162-FEDER-000086) is also acknowledged. P. M. Martins and Luciana Pereira thanks the FCT for grants SFRH/BD/98616/2013 and SFRH/BPD/110235/2015, respectively. MMF for a program Ciência 2008 fellowship. The authors thank financial support from the Basque Government Industry Department under the ELKARTEK Program. P.A.A.P. Marques thanks the grant IF/00917/2013/CP1162/ CT0016. Acknowledges also to FCT under the scope of the strategic funding of UID/BIO/04469/2013 unit and COMPETE 2020 (POCI-010145-FEDER-006684) and BioTecNorte operation (NORTE-01-0145FEDER-000004) funded by the European Regional Development Fund under the scope of Norte2020 - Programa Operacional Regional do Norte.info:eu-repo/semantics/publishedVersio

    Photocatalytic activity of TiO2/graphene and TiO2/graphene oxide nanocomposites

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    Semiconductor-based heterogeneous photocatalysis has been one of the most promising processes for the treatment of contaminated water. Among the available catalysts, titanium dioxide (TiO2) presents the best photocatalytic properties, being chemically and biologically inert, stable, non-toxic, cheap and easy to produce. However, its energy bang gap lies in the ultraviolet (UV) range, which is responsible for a reduced spectral activation, since UV radiation corresponds to only 5% of the solar spectrum [1]. For this reason, one of the main purposes of the scientific community has been to improve the photocatalytic performance of TiO2, namely through an adequate doping of this material, or through the creation of nanocomposites, to enable photocatalysis occurrence by the incidence of visible light. One alternative concerns the application of nanocomposites of TiO2 with graphene and graphene oxide to photocatalytic processes [2]. In this work, nanocomposites of TiO2 with different weight concentrations of graphene and graphene oxide (namely 0.5%, 1%, 1.5% and 3%) were synthetized by a one-step hydrothermal method and characterized in terms of morphology, crystalline structure, vibrational modes and optical band gap. The photocatalytic activity of these nanocomposites was then evaluated through the degradation of methylene blue and ciprofloxacin solutions under UV and visible radiation. The results indicated that the studied nanocomposites presented higher degradation rates of the methylene blue than the pure TiO2, which increased with the content of graphene/graphene oxide. However, these composites proved to be less suitable to degrade the ciprofloxacin solution than the pure TiO2 nanoparticles.Portuguese Foundation for Science and Technology (FCT) - UID/FIS/04650/2013, PTDC/CTM-ENE/5387/2014 and SFRH/BD/98616/2013; Basque Government Industry Department under the ELKARTEK Program.info:eu-repo/semantics/publishedVersio

    Effect of stocking density and use of environmental enrichment materials on the welfare and the performance of pigs in the growth and finishing phases

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    Aim of study: To evaluate the effects of stocking density and the use of environmental enrichment (EE) objects on the welfare and the performance of pigs in the growing and finishing phases.Area of study: The southern region of Brazil.Material and methods: A total of 240 pigs, 120 immunocastrated males and 120 females, with an initial weight of 22.38 ± 2.38 kg and mean age of 65 days, were submitted to two stocking densities conditions (0.85 and 1.28 m²pig) with and without EE for 117 days. The experimental design was a 2×2×2 factorial (two categories, two densities, and two EE conditions), with six replicates. Performance variables and behavior were evaluated.Main results: For stocking density, there was a significant difference in the finishing phase from 148 to 161 days of age for the final weight (FW), average daily weight gain (ADWG), and feed conversion rate (FCR). For the EE factor, there was no difference in any of the phases or in the overall period. In the overall period, the higher availability of space improved the results of FW (140.56 kg vs 136.63 kg), ADWG (1.005 kg vs 0.974 kg), and FCR (2.05 vs 2.10). There was no effect of EE, stocking densities, or their interaction on the frequency of different behaviors of the pigs in the growth and finishing phases.Research highlights: There was no effect of interactions between enriched environments, stocking densities, and sex for animal performance and behavioral frequencies; however, differences between the factors were observed separately. The higher availability of space improved the results of FW, ADWG, and FCR

    Phallus glutinolens

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    Phallus glutinolens is a species endemic to Brazil, occurring in fragments of Atlantic Forest in southern and southeastern regions. Up to now, there are only a few records of the species from six different sites. The total population is estimated at around 4,800 mature individuals, in one subpopulation. Based on the habitat decline within the area, we suspect a population decline around 10% in the last three generations (20 years). Phallus glutinolens is, therefore, assessed as Vulnerable C2a(ii).Fil: Trierveiler Pereira, Larissa. Universidade de Sao Paulo; BrasilFil: Vieira de Miranda, M.. Universidade de Sao Paulo; BrasilFil: Hernández Caffot, María Luciana. Universidad Nacional de Jujuy. Instituto de Ecorregiones Andinas. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta. Instituto de Ecorregiones Andinas; ArgentinaFil: Baltazar, J. M.. Universidade Federal do São Carlos; BrasilFil: Martins da Cuña, K.. Universidade Federal do Rio Grande do Sul; BrasilFil: Alves Silva, G.. Universidade de Sao Paulo; BrasilFil: Kossmann, T.. Universidade Federal de Santa Catarina; BrasilFil: Palacio, M.. Universidade Federal do Rio Grande do Sul; BrasilFil: Drechsler Santos, E. R.. Universidade Federal de Santa Catarina; Brasi
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