69 research outputs found

    Taller de empleo de sistemas de recuperación de código libre en el entorno laboral

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    proyecto de innovación docente que trata de incorporar a los contenidos de la asignatura "Búsqueda y Recuperación de Información" del Grado en Información y Documentación no solo los conceptos esenciales relativos a la Recuperación de Información, sino el contacto y conocimiento de los principales programas y Sistemas de Recuperación de Información de código libre empleados habitualmente en organismos y empresas de todos los sectores

    Occurrence and size distribution study of microplastics in household water from different cities in continental Spain and the Canary Islands

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    9 pages, 5 figures, 1 table, supplementary materials https://doi.org/10.1016/j.watres.2023.120044.-- Data availability: Data will be made available on requestThe purpose of this study was to investigate the occurrence of microplastics (MPs) in drinking water in Spain by comparing tap water from different locations using common sampling and identification procedures. We sampled tap water from 24 points in 8 different locations from continental Spain and the Canary Islands by means of 25 μm opening size steel filters coupled to household connections. All particles were measured and spectroscopically characterized including not only MPs but also particles consisting of natural materials with evidence of industrial processing, such as dyed natural fibres, referred insofar as artificial particles (APs). The average concentration of MPs was 12.5 ± 4.9 MPs/m3 and that of anthropogenic particles 32.2 ± 12.5 APs/m3. The main synthetic polymers detected were polyamide, polyester, and polypropylene, with lower counts of other polymers including the biopolymer poly(lactic acid). Particle size and mass distributions were parameterized by means of power law distributions, which allowed performing estimations of the concentration of smaller particles provided the same scaling parameter of the power law applies. The calculated total mass concentration of the identified MPs was 45.5 ng/L. The observed size distribution of MPs allowed an estimation for the concentration of nanoplastics (< 1 µm) well below the ng/L range; higher concentrations are not consistent with scale invariant fractal fragmentation. Our findings showed that MPs in the drinking water sampled in this work do not represent a significant way of exposure to MPs and would probably pose a negligible risk for human healthThe authors acknowledge the financial support provided by Plastics Europe and that of the Spanish Government, Ministerio de Ciencia e Innovación, grants PID2020-113769RB-C21/C22.With the institutional support of the ‘Severo Ochoa Centre of Excellence’ accreditation (CEX2019-000928-S)Peer reviewe

    A nationwide monitoring of atmospheric microplastic deposition

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    8 Pág.Plastic production continues to increase every year, yet it is widely acknowledged that a significant portion of this material ends up in ecosystems as microplastics (MPs). Among all the environmental compartments affected by MPs, the atmosphere remains the least well-known. Here, we conducted a one-year simultaneous monitoring of atmospheric MPs deposition in ten urban areas, each with different population sizes, economic activities, and climates. The objective was to assess the role of the atmosphere in the fate of MPs by conducting a nationwide quantification of atmospheric MP deposition. To achieve this, we deployed collectors in ten different urban areas across continental Spain and the Canary Islands. We implemented a systematic sampling methodology with rigorous quality control/quality assurance, along with particle-oriented identification and quantification of anthropogenic particle deposition, which included MPs and industrially processed natural fibres. Among the sampled MPs, polyester fibres were the most abundant, followed by acrylic polymers, polypropylene, and alkyd resins. Their equivalent sizes ranged from 22 μm to 398 μm, with a median value of 71 μm. The particle size distribution of MPs showed fewer large particles than expected from a three-dimensional fractal fragmentation pattern, which was attributed to the higher mobility of small particles, especially fibres. The atmospheric deposition rate of MPs ranged from 5.6 to 78.6 MPs m-2 day-1, with the higher values observed in densely populated areas such as Barcelona and Madrid. Additionally, we detected natural polymers, mostly cellulosic fibres with evidence of industrial processing, with a deposition rate ranging from 6.4 to 58.6 particles m-2 day-1. There was a positive correlation was found between the population of the study area and the median of atmospheric MP deposition, supporting the hypothesis that urban areas act as sources of atmospheric MPs. Our study presents a systematic methodology for monitoring atmospheric MP deposition.The authors acknowledge the support provided by Spanish Network of Plastics in the Environment, EnviroPlaNet (www.enviroplanet.net) and the financial support provided by the Spanish Government, Ministerio de Ciencia e Innovación, grants PID2020-113769RB-C21/C22. The authors would like to thank the Interdepartmental Investigation Research Service of the Universidad Autónoma de Madrid (SIDI-UAM and Segainvex) for the use of their infrastructures and their technical support. J.G.S. thanks ACIISI for the contract from the Viera y Clavijo program at the University of La Laguna (85 % co-financed by the European Social Fund).Peer reviewe

    Micellar-enhanced ultrafiltration for the removal of heavy metals from phosphorous-rich wastewaters:from end-of-pipe to clean technology

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    Abstract Fertilizer industry often generates phosphorous rich wastewaters containing heavy metals. While phosphorous is a valuable compound for the industry, heavy metals hinder the recovery of phosphorous due to their detrimental effects on human health and the environment. Consequently, heavy metals must be removed from the wastewaters. In this study the use of micellar-enhanced ultrafiltration (MEUF) was evaluated for the removal of cadmium, copper, zinc and nickel from phosphorous rich wastewaters. This study has been conducted following a systematic methodology from single metal synthetic wastewaters to more complex synthetic and real wastewaters. The experimental work was conducted in a laboratory scale stirred cell using 3, 5 and 10 kDa regenerated cellulose membranes and in a cross flow semi-pilot scale equipment using a 10 kDa spiral wound polyethersulphone membrane. Statistical design of experiments was used as the research methodology to evaluate the effect of factors on the MEUF process performance as well as for finding optimal conditions. The factors studied were heavy metal, phosphorous and surfactant feed concentrations, pH, membrane nominal molecular weight limits, transmembrane pressure and cross flow velocity. The membrane performance was characterized by the heavy metal retention/rejection coefficients and the permeate flux. The experimental results showed that the removal of heavy metals from single synthetic wastewaters by MEUF is more efficient for more diluted systems. In complex systems containing phosphorous, simultaneous removal of heavy metals was successfully achieved obtaining rejection coefficients up to 80%. Phosphorous was not retained by the membrane showing the potential applicability of MEUF to purify phosphorous rich wastewaters. The study of metal complex formation and heavy metal competition has been shown to be very important in order to predict the MEUF results. Concentration polarization phenomenon was insignificant in the synthetic wastewaters but it was more severe when applying MEUF to real wastewaters. In addition, with real wastewaters SDS leakage was insignificant. This study has provided new and valuable knowledge regarding the applicability of MEUF to industrial wastewater treatment.Tiivistelmä Lannoiteteollisuus tuottaa usein jätevesiä, jotka sisältävät huomattavia määriä fosforia, sekä pieniä määriä raskasmetalleja. Vaikka fosfori on tärkeä raaka-aine lannoiteteollisuudelle, jätevesissä olevat raskasmetallit kuitenkin estävät sen hyötykäyttöä fosforin lähteenä. Raskasmetallit ovat haitallisia sekä luonnolle että ihmisten terveydelle, joten niiden erottaminen jätevesistä on tärkeää. Tässä työssä tutkittiin miselliavusteisen ultrasuodatuksen (MEUF) käyttöä kadmiumin, kuparin, sinkin ja nikkelin poistamiseen fosforipitoisista jätevesistä. Väitöskirjatyössä tutkittiin systemaattisesti synteettisiä jätevesiä, jotka sisälsivät joko yhtä tai useita raskasmetalleja, sekä lannoitetehtaalta kerättyjä jätevesiä. Kokeet tehtiin laboratoriomittakaavan sekoituskennolla, jossa käytettiin 3, 5 ja 10 kDa:n regeneroituja selluloosakalvoja, sekä semi-pilot -mittakaavan spiraalielementillä, jonka materiaalina oli 10 kDa:n polyeetterisulfonikalvo. Väitöskirjatyössä hyödynnettiin tilastollista koesuunnittelua, jonka avulla arvioitiin muuttujien vaikutuksia MEUF-prosessin käyttäytymiseen. Koesuunnittelua hyödynnettiin myös optimiolosuhteiden määrittelemisessä. Koesuunnitelmien muuttujina olivat raskasmetallien, fosforin ja pinta-aktiivisen aineen pitoisuudet, pH, suodatuskalvojen katkaisukoot, paine sekä ristikkäisvirtauksen nopeus. Kalvon käyttäytymistä arvioitiin raskasmetallien erotustehokkuuden ja permeaattivuon avulla. Koetulokset osoittivat raskasmetallien erotuksen olevan tehokkainta synteettisistä, yhtä metallia sisältävistä jätevesistä, joiden raskasmetallipitoisuus oli pieni. Fosforia sisältävistä monimetalliliuoksista saavutettiin 80&#160;%:inen raskametallien poistotehokkuus. Kalvoerotuksessa fosforipitoisuus ei muuttunut merkittävästi, mikä osoittaa MEUF:n olevan potentiaalinen menetelmä raskasmetallien poistamiseen fosforipitoisista jätevesistä. Metallikompleksien muodostumisen ja raskasmetallien välisen kilpailun ymmärtäminen osoittautuivat erittäin tärkeiksi MEUF-tuloksien ennustamisessa. Konsentraatiopolarisaatioilmiö ei ollut merkittävä käsiteltäessä synteettisiä jätevesiä, mutta teollisten jätevesien käsittelyssä ilmiöllä oli huomattava vaikutus permeaattivuohon. Kuitenkin teollisen jätevesien käsittelyssä SDS:n vuotaminen kalvon läpi oli merkityksetöntä. Tämä tutkimus on antanut uutta ja merkittävää tietoa MEUF:n soveltuvuudesta teollisten jätevesien käsittelyn

    Circular Economy in Membrane Technology

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    The European Union (EU) produces more than 2 [...

    Recyclability Definition of Recycled Nanofiltration Membranes through a Life Cycle Perspective and Carbon Footprint Indicator

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    The direct end-of-life recycling of reverse osmosis membranes (RO) into recycled nanofiltration (r-NF) membranes has been pointed out as a circular technology. For the first time, an environmental analysis of the whole life cycle of r-NF membranes was performed, focused on their usage. The carbon footprint (CF) of NF water treatment processes (Functional Unit: 1 m3 of treated water) with different pressure vessel (PV) designs and energy sources using r-NF and commercial NF-270-400 was quantified. Moreover, to compensate for the lower permeability of the r-NF, two design strategies were assessed: A) an increment in inlet pressure, and B) an increase in the number of modules. The inventory included energy modelling for each design and membrane. The interaction of both strategies with the permeability and service life of r-NF, together with different energy sources, was assessed using a novel hybrid analytical&ndash;numerical method. The relevance of energy use at the usage stage was highlighted. Therefore, r-NF permeability is the foremost relevant parameter for the definition of CF. The low impact of the r-NF replacement favoured strategy B. The use of an environmental indicator (CF) made it possible to identify the frontiers of the recyclability and applicability of r-NF membranes

    Validation of Recycled Nanofiltration and Anion-Exchange Membranes for the Treatment of Urban Wastewater for Crop Irrigation

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    One of the alternative sources to tackle the problem of water shortage is the use of reclaimed water from wastewater treatment plants for irrigation purposes. However, when the wastewater has a high conductivity value, it becomes unusable for crop irrigation and needs a more specific treatment. In this work, recycled nanofiltration (rNF) membranes and anion-exchange membranes (rAEMs) obtained from end-of-life RO membranes were validated to evaluate their application capability in saline wastewater treatment. The use of recycled membranes may represent an advantage due to their lower cost and reduced environmental impact associated with their production, which integrates membrane-based technology into a circular economy model. Both recycled membranes were tested in crossflow filtration and electrodialysis (ED) systems. The results of the rNF membrane showed a high selective rejection of divalent ions (SO42− (>96%) and Ca2+ and Mg2+ (>93%)). In the case of the ED process, the comparison between rAEMs and commercial membranes showed an appropriate demineralization rate without compromising the power consumption. Finally, the quality of both system effluents was suitable for irrigation, which was compared to the WHO guideline and validated by the 7-week lettuce crop study
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