Percorrer por autor "Queiroz, Ana"
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- 14th International Chemical and Biological Engineering Conference (CHEMPOR-2023): Book of AbstractsPublication . Queiroz, Ana; Peres, António M.; Ribeiro, António E.; Barreiro, Filomena; Ferreira, Olga; Brito, Paulo; Pinho, SimãoWelcome to the 14th edition of the International Chemical and Biological Engineering Conference (ChemPor-2023) held at Bragança Polytechnic University (Instituto Politécnico de Bragança, IPB), Portugal, from 12 to 15 of September, 2023. This triennial conference, organized by a Portuguese Higher Education Institution and the Portuguese Engineers Association (Ordem dos Engenheiros), gathers experts from the chemical and biological engineering areas and related subjects to exchange knowledge and technological experiences within the academic, industrial, scientific, and technological communities. ChemPor-2023 addresses these research fields in different topics, from green chemistry to engineering education, always envisaging a sustainable development. The etymology of the word “conference”, from the Medieval Latin, means literally “bring together”. This 14th edition comes with a two-year delay following the global sanitary crisis since only a full inperson meeting could fulfill this purpose. ChemPor-2023 encompasses a gathering in a vivid, enlightening, and convivial way, and this hiatus did not limit this spirit or its objectives. The conference aims to celebrate creativity, diversity, and friendship among participants, promoting ideas exchange and fruitful interactions. We have circa 300 delegates from 4 continents, and your active participation is highly acknowledged. The general relevance of ChemPor-2023 is addressed in a variety of settings, including biorefinery, biotechnology, energy and environment, innovative materials, creation and design of novel reaction and separation processes, always foreseeing industrial applications for a sustainable shaping of the future. This edition includes an opening lecture by Jorge Calado in the immense but much less explored area of ArtScience, and an Honor Session dedicated to Alírio Rodrigues for his academic and scientific contributions, particularly regarding IPB. Besides, the conference includes 11 invited lectures from internationally recognized scientists and experts from the industry, 107 oral presentations distributed in 27 sessions, and 135 posters in two dedicated sessions. A session exclusively dedicated to companies and another for Ph.D. studies in industrial environments are to be highlighted. The “Professor Almiro e Castro” award, established in 2014 by PARALAB – Equipamentos Industrial and Laboratory SA, to recognize the scientific merit of a Portuguese professor or researcher in the last three years in the fields of Chemical and Biological Engineering, and related areas, will be announced at the closing of the conference. In that ceremony, the two best posters and the best oral communication awards by young scientists will also be granted. We want to reinforce our deepest appreciation to all the participants, but also to the members of the Honor, Scientific, and Local Organizing Committees for their invaluable contribution to the conference and acknowledge the institutional support of Instituto Politécnico de Bragança, Ordem dos Engenheiros, Centro de Investigação de Montanha, Sociedade Portuguesa de Química, and Câmara Municipal de Bragança. Expressing enormous gratitude is mandatory to all our Sponsors and associated scientific journals and publishers. Nothing could have been possible without all of you! Finally, our best wishes for success for the next ChemPor organization.
- Acid leaching of alloys within the quaternary system Fe-Si-Ca-AlPublication . Margarido, Fernanda; Figueiredo, Maria Ondina; Queiroz, Ana; Martins, João Pedro de AlmeidaSilicon with high purity and fine particle size can be produced by acid leaching of Fe-Si industrial alloys under the condition that they have adequate chemical composition and structural constitution. Such alloys contain phases that fall within the system Fe-Si-Ca-Al, where the quaternary phase Caalsifer, with aproximate formula (Fe0.8Al0.1 0.1) (Si0.8Ca0.2)2, is found along with several binary and ternary phases (Fe-Si, Ca-Si, Al-Fe-Si, Ca-Al-Si). With the purpose of optimizing the phase, constitution alloys were synthesized within the system Fe-Si-Ca-Al. The results of leaching experiments performed using HCl (150 and 220g/L) at constant temperature (T=102 1 C) and ordinary atmosphere indicate that the Caalsifer plus Al-Fe-Si phases should be maximized whereas the FeSi2 phases should be minimized, by controlling Al/Ca and Fe/Si concentration ratios in the synthesis process.
- Acid refining of synthesised alloys within the quaternary system Fe-Si-Ca-Al: effect of ferric ionsPublication . Queiroz, Ana; Margarido, Fernanda; Martins, J.P.A systematic study of synthesis of different chemical composition of alloys within the quaternary Fe-Si-Ca-Al system, versus acid leaching refining using HCl with or without FeCl3 has been undertaken. Such study has the aim of achieving an adequate structural composition of Fe-Si alloys, in order to obtain high purity and fine particle size silicon by acid leaching, at more reduced costs. The experimental results show that an adequate control of Fe/Al and Si/Ca concentration ratios can hinder the formation of tetragonal and orthorhombic FeSi2 phases, and consequently promotes a successful refining of ferro-silicon alloys. The presence of ferric ion influences on a distinct way the rate of removal of Al-Fe-Si and Fe-Al-Si-Ca phases, increasing the first and decreasing the second one. The suitable starting composition which could give the expected results must be the following: 92-94% Si; 3-3.5% Fe; 3.5-4% Al and Ca ≤ 0.5%.
- Acidic waste cooking oil valorization by biodiesel synthesis catalyzed by hydrogen sulfate 1-butyl-3-methylimidazoliumPublication . Baú, Ana; Lenzi, Giane G.; Ribeiro, António E.; Queiroz, Ana; Brito, PauloBiodiesel is a fuel that shows growing demand as a promising alternative to petroleum-derived fuels. It is produced by esterification or transesterification reactions from renewable raw materials such as animal fats and vegetable oils , where the presence of catalysts is used for an effective conversion. The basic catalysts are very sensitive to the presence of water and FFAs, promoting saponification reactions. On the other hand, the use of acid catalysts means reaction times up to 4000 times higher, higher alcohol/oil molar ratios and higher reaction temperatures. In this context, Ionic Liquids (ILs) used as catalysts, come as a viable alternative to overcome these problems in biodiesel production processes. Imidazolium-based ILs, have been extensively studied, mainly due to their specific characteristics such as, low pressure and ability for self-organization in different states. Hydrogen sulfate 1-butyl-3-methylimidazolium [BMIM]HSO4 has been showing promising results in this type of applications. Therefore, the objective of this work is to study the application of the [BMIM]HSO4 IL in the catalysis of esterification/transesterification reactions of triglycerides mixtures with high free fatty acid contents coming from waste cooking oils samples, with further characterization of the quality of the biodiesel produced. The present work includes also the assessment of the catalyst potential for recovery and recycling.
- Acidic waste cooking oil valorization by biodiesel synthesis catalyzed by hydrogen sulfate 1-butyl-3-methylimidazoliumPublication . Baú, Ana; Lenzi, Giane G.; Ribeiro, António E.; Queiroz, Ana; Brito, PauloBiodiesel is a fuel that shows growing demand as a promising alternative to petroleum-derived fuels. It is produced by esterification or transesterification reactions from renewable raw materials such as animal fats and vegetable oils , where the presence of catalysts is used for an effective conversion. The basic catalysts are very sensitive to the presence of water and FFAs, promoting saponification reactions. On the other hand, the use of acid catalysts means reaction times up to 4000 times higher, higher alcohol/oil molar ratios and higher reaction temperatures. In this context, Ionic Liquids (ILs) used as catalysts, come as a viable alternative to overcome these problems in biodiesel production processes. Imidazolium-based ILs, have been extensively studied, mainly due to their specific characteristics such as, low pressure and ability for self-organization in different states.
- Avaliação da atividade antimicrobiana de óleos essenciais de eucalipto (Eucalyptus globulus)Publication . Cidres, Eliana Soraia Santos Alves; Queiroz, Ana; Amaral, Joana S.A espécie E. globulus é considerada a principal fonte mundial de óleo de eucalipto, sendo este constituído por uma ampla gama de compostos, sendo o mais importante o monoterpeno 1,8-cineol. O óleo de eucalipto é amplamente utilizado para fins medicinais, tais como alívio da tosse, dor de garganta e outras infeções, como antissético e utilizado como ingrediente em produtos farmacêuticos e cosméticos. O objetivo deste trabalho foi avaliar a atividade antimicrobiana de óleos essenciais do fruto e folhas do eucalipto obtidos por hidrodestilação em aparelho de Clevenger e também de dois óleos comerciais. No estudo usaram-se bactérias Gram-positivas (Staphylococcus aureus, Bacillus cereus, Bacillus subtilis, Enterococcus faecalis), Gram-negativas (Escherichia coli, Klebsiella pneumoniae, Enterobacter sp., Proteus mirabilis, Pseudomonas aeruginosa) e o fungo Candida albicans. A atividade antimicrobiana dos óleos essenciais do fruto e folhas do eucalipto foi avaliada pelo método da macrodiluição em caldo, tendo sido testadas diferentes concentrações (2,5% a 0,04%, v/v) para determinação da concentração mínima inibitória (CMI). O estudo realizado mostrou que os óleos essenciais comerciais (n=2) e extraídos das folhas (n=3), apresentaram atividade inibitória no crescimento de todos os microrganismos estudados à exceção de P. aeruginosa, cujo crescimento não foi suscetível à presença dos óleos essenciais, mesmo na concentração mais elevada (2,5% v/v). De uma forma geral, o óleo essencial do fruto apresentou uma eficácia inferior comparativamente às amostras comerciais e das folhas, à exceção da bactéria S. aureus, para a qual a amostra do óleo de fruto apresentou o mais baixo valor de CMI (0,16%, v/v).
- Biodiesel production by transesterification using choline hydroxide as catalystPublication . Brito, Paulo; Lima, Renata; Queiroz, Ana; Ribeiro, António E.Biodiesel is a mixture of fatty acid methyl esters (FAMEs) and is a biodegradable and renewable fuel, produced from fat sources mainly composed of triglycerides. The use of ionic liquids (ILs) in biodiesel catalytic production has been studied mainly in the ecological field, as it allows a high recycling efficiency. Choline (2-hydroxyethyl trimethylammonium)-based ILs have received attention due to their biocompatibility characteristics and potential for various industrial applications. Specifically, choline hydroxide (ChOH) represents a promising option. This work's objective is the optimization of the methyl transesterification reaction conditions using commercial and waste sunflower oil (WSO) as raw material and ChOH as a catalyst, assessing the possibility of recovering the catalyst between reaction cycles. Therefore, biodiesel production was carried out on heating plates with temperature control and with magnetic stirring, using methanol reflux. After phase separation, centrifugation was used to enhance biodiesel recovery. Reaction conversion was assessed by acidity drop determination, and the biodiesel FAME content was determined by GC-FID, through a procedure in accordance with EN 14103, using methyl heptadecanoate as the internal standard. IL recovery was carried out by solvent extraction with water-based binary systems, followed by an FTIR analysis of both phases for ChOH detection, and a comparison with initial IL samples. Optimal conversions, determined by acid value (AV) reduction or by biodiesel FAME mass content, were obtained using a 4%wt. catalyst load, oil/methanol molar ratio of 1:8, duration of 1 h, and temperature of 65 °C. The products’ AV for WSO showed a significant reduction relating to the raw material AV (6.14 mgKOH/g). For the reactions with commercial sunflower oil (AV close to 0.20 mgKOH/g), the biodiesel phase AV remained low. ChOH recovery, performed with n-butanol/water and ethyl acetate/water systems, proved to be inefficient under the conditions tested. FTIR analysis showed the presence of ChOH in both liquid–liquid extraction phases.
- Biodiesel production by transesterification using choline hydroxide as catalystPublication . Lima, Renata; Queiroz, Ana; Ribeiro, António E.; Brito, PauloBiodiesel is a mixture of alkyl esters derived from vegetable oils or animal fat. Itis a biodegradable and renewable fuel and does not contribute to the emission of polluting gases into the atmosphere. Still, its major disadvantage is its relatively high cost, usually regarding production and raw materials costs (Langet al., 2001). Crude oils and fats extracted from plants and animals are alternatives to highly polluting fossil fuels. They are composed of triglycerides, which can be converted into biofuels through transesterification processes. The alcoholysis of vegetable oils or animal fats may be carried out using different catalysts: acids, bases, and enzymes. Basic catalysts, sodium or potassium hydroxide, are about 4,000 times faster than acid catalysts and do not require large amounts of alcohol. On the other hand, ionic liquids (ILs) use in catalytic processes has been studied mainly in the ecological field, as it allows a high recycling efficiency. ILs based on the choline cation (2-hydroxyethyl trimethylammonium) have received much attention, mainly due to its biocompatibility characteristics and potential for various industrial applications. Choline hydroxide (ChOH – see Fig. 1) in particular represents a promising option due to its good catalytic performance in methanol solution and its successful reuse (Fan et al., 2013). This work's main objective was to optimize the methyl transesterification reaction conditions using commercial and waste sunflower oil as raw material and ChOH as catalyst. The possibility of recovering the ChOH catalyst between reaction cycles was also assessed.
- Biodiesel production from residual cooking oils and its purification by adsorption processes based on adsorbents of natural originPublication . Garção, Maria Isabella Lima; Gomes, Maria Carolina Sérgi; Queiroz, Ana; Ribeiro, António E.; Brito, PauloTotal global energy consumption has increased significantly in recent decades, and nowadays the main sources of world energy are oil, coal and natural gas. In addition to environmental concerns, the limited availability of fossil fuels has increased the interest in exploring alternative energy sources. In this quest, biofuel is a promising renewable energy source with low carbon emissions, also, it can be produced from a variety of resources, including waste cooking oil (WCO). Biodiesel is renewable, biodegradable, non-toxic, sulfur-free and free of aromatic carcinogens
- Biodiesel production from residual cooking oils and its purification through adsorption processes using activated carbon prepared from cork wastePublication . Garção, Maria Isabella Lima; Queiroz, Ana; Brito, Paulo; Ribeiro, António E.; Gomes, Maria Carolina SérgiBiodiesel is a renewable fuel that can be produced from waste cooking oil mainly through transesterification. However, from its production results a contaminant called glycerol, which must be removed. Wet washing is the most common method for biodiesel purification, but it has several drawbacks, including high costs and the generation of large amounts of aqueous effluent. This study proposes using activated carbon obtained from industrial cork waste in adsorption as an alternative method for glycerol removal. This approach could potentially reduce the environmental impact and cost of producing biodiesel, while also providing an alternative for the valorization of industrial cork waste. The highest value of removal of 89% of glycerol occurred with a cork chemically activated carbon with KOH at a load of 2%wt at 25°C for 6 hours of contact. After the biodiesel washing using adsorption process, the remaining glycerol content was 0.016%wt, below the maximum value of 0.02%wt specified by the EN14214:2012 standard.