Browsing by Issue Date, starting with "2023-06"
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- Retratação: Contaminación antrópica en un acuífero fracturado en UruguayPublication . Comissão Executiva das Comunicações GeológicasA Comissão Executiva (CE) das Comunicações Geológicas (CG) tomou a decisão de retratar o artigo em epígrafe, após confirmação de plágio e fortes indícios de fabricação e falsificação de dados a partir do artigo [1]. Na ausência de uma resposta satisfatória no prazo que lhes foi fixado para o efeito, a CE das CG assumiu que os autores do artigo publicado nas CG aceitam os factos e as conclusões do inquérito que lhes foram apresentados. Esta nota de retratação é feita sem a colaboração desses mesmos autores.
- Efficient conversion of agricultural and forest residues into bioethanol: BIOFLEXPOR as flexible technology towards sugar-based biorefineries [Poster]Publication . Marques, Susana; Paixão, Susana M.; Alves, Luís; Gomes, Miguel; Eusebio, Ana; Lopes, Tiago; Coelho, Lucas; Diebold, Eduardo; Gírio, FranciscoABSTRACT: Lignocellulosic ethanol is in the upfront of advanced biofuels to be commercialized worldwide. However, the commercial deployment of 2G ethanol is dependent of high biomass availability and cost-effective supply. In Europe, some agricultural residues are presently underused and constitute attractive renewable resources. In addition, residual forest biomass, non-seasonably available at low cost, might be complementarily used as raw material boosting the economy of biorefineries. In this context, the present work deals with the development of an innovative and sustainable technological strategy to produce advanced bioethanol using agricultural and forestry residual biomass. The bioprocess involves enzymatic hydrolysis of major lignocellulose polysaccharides (cellulose and xylan) with commercial enzymes and fermentation of the resulting sugars. A pre-treatment step should firstly be accomplished to make cellulose more amenable to hydrolytic enzymes, and the prototype is based on a proprietary non-catalysed steam explosion technology, i.e., without the addition of acids and using only high-pressure steam, called FLEXBIO™, which was initially developed in Brazil by the company STEX and since 2019 in partnership with LNEG. The proposed technology has been successfully demonstrated in a relevant environment (TRL 5) for the efficient conversion of corn stover, olive tree pruning and eucalyptus-based forest residual biomass, yielding close to 150 L of ethanol per metric tonne (dry basis) of biomass, corresponding to an overall yield close to 75% of maximal theoretical yield for glucan conversion. Both enzymatic hydrolysis and fermentation steps have achieved yields superior to 85% of the maximal theoretical conversion, and the optimization of process configuration, targeting the best integration with pre-treatment, is now under progress and higher yields will be expected. Given the higher xylan content of corn stover, both cellulose and xylan fractions are pursued. In addition, the upgrading potential of all wastewater streams will also be assessed, by studying the feasibility of its combined use to increase the ethanol yield as alternative to its use for biogas production through anaerobic digestion, with the goal to reach near-zero waste. In conclusion, the present study reveals the industrial potential of this flexible technology that might be applied to implement distinct small-scale sugar-based biorefineries by converting several lignocellulosic raw materials into distinct marketable biofuels/biomaterials, promoting the circular bioeconomy.
- Advances in electrochemical reduction of CO2 in ionic liquid-based electrolytes [Resumo]Publication . Machado, Ana; Messias, Sofia; Paninho, A. B.; Nunes, A. V. M.; Rangel, C. M.; Branco, Luis CABSTRACT: Electrochemical reduction of CO2 was for the first time reported in 1870 [1], but it was only after 2010 that this field was the subject of intense research efforts. The use of renewable electricity to convert CO2 into products that are currently derived from fossil products and have high carbon footprint will certainly make this technology one pillar of a sustainable chemical industry. The scepticism towards the availability of cost effective products derived from CO2 electro-reduction that customers will be willing to buy has shifted to the belief that they can be commercially viable. Turning electrochemical CO2 reduction into a commercial technology will depend on economics, on the price of electricity, efficiency of the process and the value of the products. One way to improve the economics and improve the efficiency of the process is to integrate CO2 capture with conversion [2,3]. In this way the energy intensive regeneration step of the capture media can be eliminated and also CO2 transportation and storage. Ionic liquids are ideal media to achieve this integration, due to high CO2 adsorption capacity, high selectivity, wide electrochemical windows and nearly zero vapour pressure. The present work reports the progress of electrochemical reduction of CO2 in ionic liquids and the work of the authors in this field. It has been recognized that ionic liquids promote CO2 electro-reduction through lowering the reduction potential, the suppression of the competing hydrogen evolution reaction and by increasing the selectivity towards the target products. However, the understanding of the interactions between ionic liquids, CO2 and catalyst is still quite limited, but fundamental for synthetizing more efficient electrolytes for CO2 electro-reduction [4]. Thus, current cation and anion effects will be analysed and an overview of the current performance of heterogeneous electro-catalysts in ionic liquid- based electrolytes for CO2 electro-reduction will be provided.
- The Stability of Tio₂-rGO Self-Cleaning Photocatalytic Coatings for Outdoor ApplicationsPublication . Covei, M.; Tismanar, I.; Cunha Diamantino, TeresaABSTRACT: Self-cleaning coatings are lately being studied for different applications such as civil buildings (windows, facades, indoor walls, metallic products), the automotive industry (mirrors, windshields, the health field (surgical rooms' walls or tiles) and renewable energies, namely for solar energy (solar reflectors, photovoltaic panel). The self-cleaning occurs through two mechanisms that involve (1) (super)hydrophobic coatings, when the pollutant rolls off the surface without being degraded or (2) (super)hydrophilic coatings, when the pollutant is dissolved in the water sheet and afterwards is degraded through the photocatalytic process (Merai et al., 2019). The most-used photocatalytic material is titanium dioxide (TiO₂) because of its non-toxicity, acceptable production cost and possible anticorrosive properties. The main disadvantage of TiO₂ is related to its UV activation which leads to additional process costs. Recent studies indicate the Vis- or solar-active composite materials (such as TiO₂ - rGO composites) as a solution to overcome the activation problem (Tismanar et al., 2021; Covei et al., 2022). However, for outdoor applications, their stability under environmental conditions (high temperature and humidity or highly corrosive atmospheres) must be analyzed. This research reports on the stability of the TiO₂/TiO₂-rGO double-layered composite thin films deposited on 5x5cm² Al substrates using up-scalable and low-cost deposition methods (spray pyrolysis deposition for TiO₂ intermediate layer coupled with sol-gel spraying for the TiO₂-rGO composite second layer).
- Natural Stones from Portugal : Proposal for harmonizing Commercial NamesPublication . Carvalho, Jorge; Carvalho, Cristina Isabel Paulo; Lopes, Luis; Silva, António; Santos, Catarina; Sousa, Luís; Martins, Ruben; Marques, CéliaABSTRACT: Over the years, the Portuguese Geological Survey – LNEG, has been dedicated to the characterization of Portuguese natural stones. Today, a newly updated LNEG web portal contains information on 149 natural stones, which are known by their unique trade names. Many of these names integrate the EN 12440 - Natural Stone - Denomination Criteria standard, but others do not. Furthermore, there many other names used to identify natural stones that are traded today and that do not integrate the LNEG web Portal or the EN 12440. This work presents a harmonization proposal for the commercial denomination of the Portuguese natural stones. It is a working basis for a final list that must be submitted to ISO/Technical Committee 118 – Natural Stones.
- Sustainable public procurement: a contribution to achieving low carbon footprint buildingsPublication . Duarte, Ana Paula; Farto, Ana; Trindade, PaulaABSTRACT: LIFE ReNatural NZEB project and is part of action B3 of the project "Demonstration experiences of NZEB with low carbon footprint". The article intends to present the results obtained in the development of the model, for which two surveys were sent to several construction companies and material supplying companies. These surveys aimed at knowing the market's ability to comply with the sustainability criteria for low carbon footprint residential buildings. The model was defined based on the analysis of national and international good practices that were collected, the EU GPP criteria and the manual "Green Public Procurement Criteria under ENCPE 2020 for Design, Construction and Management of Office Buildings". The model is divided into five parts: selection of the design team and contractors; detailed design and performance requirements; dismantling, demolition, and site preparation works; construction of the building or major renovation works; and finalization and handover. Overall, it was found that companies in the construction sector can meet most of the selection criteria for the design team and contractors and for some of the technical specifications. It was also found that material suppliers can meet the various sustainability criteria for materials.
- European policies on Circular Economy and Climate Mitigation: synergies or antagonisms?Publication . Trindade, Paula; Barbosa, Juliana; Amorim, Filipa; Simoes, Sofia; Lima, Ana TeresaABSTRACT: The main objective of this paper is to review policy goals, measures and instruments across the following policy areas: climate, energy; environment (including CE) and industry. This review's objective is twofold: (1) to assess and characterise synergies and antagonisms among policy domains regarding CE and climate mitigation, and (2) to identify innovative and effective policy approaches for integrating CE into climate action. The analysis will focus on the EU+ policy level, with some incursions at Member State level (+UK) for the cases where best practices in integrating CE policies are identified. The policies assessment will feed into the climate mitigation scenarios for circular construction.
- Mortars from the Monastery of Santa Maria de Alcobaça, in Portugal: characteristics and functionsPublication . Carvalho, Fernanda; Lima, M.M.R.A.; Silva, Teresa; Nunes, A.; Pagará, A.; Costeira, I.; Leal, Nuno; Simão, J.; Galhano, Carlos; Veiga, JP
- A Pedra Natural Portuguesa : Proposta de harmonização de Designações ComerciaisPublication . Carvalho, Jorge; Carvalho, Cristina Isabel Paulo; Lopes, Luis; Silva, António; Santos, Catarina; Martins, Ruben; Marques, Célia; Sousa, LuísRESUMO: No início dos anos 80 do século passado, o LNEG – Laboratório Nacional de Energia e Geologia (Serviços Geológicos de Portugal), através das suas instituições públicas antecessoras, deu início à caracterização e à inventariação das rochas ornamentais extraídas em Portugal. Deste trabalho inaugural resultou o primeiro Catálogo de Rochas Ornamentais Portuguesas, publicado em 4 volumes entre 1983 e 1994, complementado por 8 fichas técnicas editadas entre 1995 e 2000. Em 2002, a 1ª versão em formato digital do catálogo começou a ser desenvolvida, tendo sido incluída no site do LNEG como o Portal das Rochas Ornamentais Portuguesas – ROP. Foi atualizado em 2021 (https://geoportal.lneg.pt/pt/bds/rop/), englobando toda a informação contida no catálogo, além de novas funcionalidades como a “pesquisa por critérios”, tais como a designação comercial, o município de exploração, a cor, assim como diversas características tecnológicas. Ao longo dos anos, novas pedras foram acrescentadas ao ROP, que atualmente contém a informação relativa a 149 litótipos comerciais portugueses.
- A novel bench-scale photobioreactor for continuous cultivation of microalgae [Poster]Publication . Silva, Tiago; Tavares, João; Paixão, Susana M.; Alves, LuísABSTRACT: There are different types of carbon intensive industries. While some operate with daily intervals, others must be maintained in continuous operation, sometimes for weeks or months. Processes that depend on microbiological activity are usually of the second category, resulting in the continuous production of CO2 during extensive periods of time. In order to help mitigate climate change, alternative methods of carbon capture into added-value products have been the focus of research. Autotrophic microalgae cultures can be employed to sequester the carbon present in these streams, generating new products, while increasing process sustainability. However, to sequester these emissions microalgal bioreactors must also function under continuous constant conditions, requiring photobioreactors (PBRs) that can act as chemostats for long periods of time. Moreover, there is currently a lack of studies and design alternatives using microalgal chemostats. Most works tend to focus on batch assays or semi-continuous processes, presenting different responses depending on the growth stage of the culture, or the time of day. The present work is centred on the development of a novel continuous bench-scale PBR. This system uses an innovative recirculation concept to combine three different units (retention vessel, photocollector and degasser) that operate as a single autotrophic chemostat, allowing the study of carbon sequestration from a biogenic CO2-rich constant air stream. The novel PBR was tested by cultivating the microalga Haematococcus pluvialis at different dilution rates (0.1-0.5 d-1), while using as sole carbon source an air stream containing ≈0.35 vol% of CO2 (produced by a coupled heterotrophic bacterial chemostat). The results obtained revealed that the system could operate as a chemostat, allowing the production of stable cultures with proportional responses to the changes in dilution rates for more than 3 months, reaching a maximum biomass productivity of 183 mg/L/d, with a carbon fixation efficiency of ≈39% at 0.3 d-1. This makes the PBR prototype a promising tool to study/optimise integrated heterotrophic and autotrophic continuous processes, or constant sequestration of stable CO2-rich streams, making it easier to gather data for future scale-up.