ISEL - Eng. Quim. Biol. - Posters
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- An AFM, TEM, XRD and luminescence study of carbon nanomaterials obtained from cork industry wastewaterPublication . Prata, José Virgílio; Monteiro, O. C.; Silvestre, António Jorge; Viana, A. S.; Costa, AlexandraQuercus suber L. (cork oak) contributes significantly to the economies of several European Union countries. The industrial processing of cork planks involves a cooking operation in which the textural and plastic properties of cork are improved. The resulting wastewater (ca. 400 L/ton of processed cork) is rich in water-soluble extractives, namely phenol- and polyphenol-based compounds and pectins. While the presence of these and other compounds usually defy several spent water treatment processes owing to their inherent poor biodegradability, they represente otherwise a huge opportunity to produce high-valued carbon-based materials.
- Bright nanoparticles for an even brighter future: efficient production of luminescent carbon nanodots from olive mill wastewaterPublication . Sousa, D. A.; Costa, Alexandra; Alexandre, M. R.; Prata, José VirgílioCarbon nanodots (CNDs) are a very recent class of spherical-shaped nanosized carbon materials possessing average typical diameters < 10 nm. Since the very first reports on carbon dots,1,2 a variety of methods (top-down and bottom-up strategies), carbon sources and passivating agents, have dealt with their synthesis.3 The bottom-up approach, encompassing the use of pyrolytic/solvothermal processes, is more amenable for large-scale production and can cope with a large diversity of carbon precursors, either from natural or synthetic sources, typically endowed with acid, alcohol and amine functionalities.4 Some of the interesting CNDs properties include tunable photoluminescence, outstanding photostability and negligible cytotoxicity. These unique properties have prompted their intense and widespread use in several fields, such as fluorescent bioimaging and nanomedicine, chemo/biosensing, photocatalysis and optoelectronics.4
- Carbon dots from cork industry wastewater as reusable catalysts for alcohols oxidationPublication . Martins, Luisa; Prata, José VirgílioSelective oxidation of alcohols plays a central role in many important and relevant industrial processes, from commodities to pharmaceuticals. In recent years, metal-based catalytic processes, either homogeneous or heterogeneous, have superseded the classical oxidation methodologies based on stoichiometric amounts of hazardous oxidants. Particularly, the last 15 years witnessed an astonishing development of catalytic systems that rely on metal or organocatalysts in conjunction with environmentally acceptable oxidants such as hydrogen peroxide and dioxygen. Carbon-based nanomaterials have more recently entered the field of catalytic oxidations. Herein, carbon dots produced from cork industry wastewater are provided to design improved catalytic processes for selective oxidation reactions of industrial interest such as the oxidation of primary and secondary alcohols to, respectively, aldehydes and ketones. The activity of the prepared materials was tested in batch and the effects of reaction parameters, such as reaction time, temperature, type and amount of oxidant are reported and discussed.
- Carbon nanodots from olive mill wastewater: a sustainable routePublication . Sousa, D. A.; Costa, Alexandra; Alexandre, M. R.; Prata, José VirgílioOlive oils are obtained from the fruit of the olive tree (Olea europaea L.) by combined mechanical and physical operations. Portugal has a significant production of olive oil (76 k tonnes/year over the last 5 years, 2010-2015) [1]. Olive oil is typically obtained by two main processes: batch press and continuous centrifugation. Depending on the particular process used, 200-1600 L of olive mill wastewater (OMWW) is produced per tonne of processed olives. Taken the lowest of these values, an estimate points to around 15 million L of OMWW may be produced each year in Portugal. The OMWW exhibits very low biodegradability parameters which pose serious issues for its treatment. Sustainable production of high-valued carbon materials from industrial lowvalued and problematic wastes is particularly appealing and highly desirable.
- Conversão de dióxido de carbono em combustíveis sintéticos renováveis, através de um processo eletroquímicoPublication . Guerra, Luís Filipe; Rodrigues, J.; Puna, Jaime; Gomes, João; Santos, Maria TeresaProjeto que contempla um processo eletroquímico inovador de produção de combustíveis sintéticos renováveis a partir da conversão de CO2; Tecnologia emergente alternativa aos processos termoquímicos de oxidação de carbono (steam reforming e gaseificação do carvão); Os principais combustíveis a ser produzidos por esta via são: metanol, metano, DME, entre outros.
- Evaluation of the molecular architecture of fluorescence calix[4]arene-based sensors in detection of toxic metalsPublication . Costa, Alexandra; Barata, Patrícia; Fialho, Carina B.; Prata, José VirgílioChemical sensors have been playing a crucial role in analytical chemistry, bio-medicinal science and environmental chemistry. Chemosensors offer na accurate and low-cost finding of anions, cations, enzymes and toxic metal ions with high selectivity and sensitivity. In this regard, many organic compounds have been synthesized and are being used as successful chemosensors, however calixarenes offer distinct advantage in term of selectivity and the easy incorporation of a fluorophore into the structure. Cation complexing ligands containing calix[4]arene have been used to obtain more selective metal ions receptors. Herein, we report fluorescente calix[4]arene-based sensors with diferente molecular architecture [3] and their potentialities to address the detection of toxic metals. Using fluorescence as the signal transduction technique, experiments have shown that CALIX-OCP-2-CBZs are the most sensitiveto Cu.
- Exposição profissional a nanopartículas na fabricação de peças por soldadura a laserPublication . Esteves, H.; Gomes, João; Miranda, R.; Albuquerque, PaulaA soldadura é o principal processo industrial utilizado para unir metais. Contudo, pode produzir fumos nocivos para a saúde dos trabalhadores e estima-se que, presentemente, 1-2% de trabalhadores (cerca de mais de 3 milhões), estejam sujeitos à ação de fumos e gases de soldadura. Os riscos inerentes aos processos de soldadura podem ser classificados como riscos decorrentes de agentes físicos e riscos relacionados com os componentes químicos. Por outro lado, as propriedades físicas e químicas dos fumos e os fatores individuais dos trabalhadores são fatores preponderantes na deposição de partículas inaladas. No entanto, ainda existem incertezas sobre o papel das partículas finas e ultrafinas (nanopartículas) em relação a outros poluentes atmosféricos que causam efeitos adversos para a saúde. A nível dos processos de soldadura, diversos autores demonstraram um aumento da incidência de doenças respiratórias de quatro vezes na incidência de asma entre soldadores dos Estados Unidos da América (EUA) em relação à população geral, e um aumento de duas vezes na capacidade de resposta das vias aéreas em soldadores versus não-soldadores no mesmo ambiente de trabalho. A exposição a fumos de soldadura no corpo humano pode despoletar o aparecimento de efeitos diferentes dependendo da composição desses fumos. Algumas dessas composições têm efeitos a curto prazo, tais como a designada “febre do soldador”. Contudo, os fumos de soldadura podem provocam efeitos a longo prazo nomeadamente: irritação da pele, irritação do trato respiratório, lesões nos rins e fígado, efeitos dermatológicos, doenças pulmonares do tipo asmáticas; efeitos crónicos que incluem cancro (nariz, laringe, pulmão). Estas situações de exposição profissional são de elevada complexidade e envolvem a componente inerente ao indivíduo, às condições de trabalho e à atividade desenvolvida sendo necessário aplicar uma abordagem integrada no processo de diagnóstico, avaliação e gestão do risco, adaptada a cada situação específica.
- Highly selective and sensitive detection of toxic metals by fluorescent Bicyclic Calix[4]arene-based sensorsPublication . D. Barata, Patrícia; Fialho, Carina B.; Prata, José Virgílio; Costa, Alexandra I.Development of fast and portable chemosensors for trace detection of toxic metals, in particular those which are mostly present in the environment due to natural phenomenon and human activities (e.g. cadmium, mercury and lead), is a challenging area of current research.1 Calixarenes are one of the most widespread scaffolds in host-guest chemistry because of their rigid structures, which make them perfect candidates for complexation studies with ions and neutral molecules. Metal ions commonly bind at the lower rim of the calixarene moiety. Host-guest interaction can be enhanced by proper choice of additional binding sites containing nitrogen, oxygen, sulfur or a combination of them, and specifically designed calixarene architectures. Exploring the inherent capabilities of certain fluorescent calixarene-based compounds for establishing strong host:guest interactions, several sensing materials have been developed and tested by us towards the detection of neutral molecular species.2. We report in this communication the chemosensing ability of CALIX-OCP-CBZ and CALIX-OCP (Scheme 1) towards the detection of toxic metals, either by using the sensing element in fluid phase or solid state.
- Influence of extraction process on the luminescent properties of carbon nanomaterials derived from olive mill wastewatersPublication . Sousa, D. A.; Costa, Alexandra; Alexandre, M. R.; Prata, José VirgílioIn an accompanying communication [1], we have revealed that nanosized carbon materials could be easily obtained from olive mil wastewater (OMWW) using green, sustainable and simple technological processes. In this contribution we will essentially focus on the study of the impact of the effluent nature on the structural, morphological and luminescente characteristics of synthesized carbon nanodots (CNDs).
- Metal ion recognition induced by calix[4]arene carbazole containing polymersPublication . D. Barata, Patrícia; Costa, Alexandra; Fialho, Carina B.; Prata, José VirgílioSensing and recognition of ions and neutral molecules via synthetic receptors are of current interest in supramolecular chemistry because of their significant importance in several areas, such as chemistry, biology and environment. Compared with small molecules, polymers-based sensors displayed several importante advantages like signal amplification. In this way, the incorporation of molecular receptors such as calixarenes with conjugated polymer backbones is expected to enhance the signaling events related to a host–guest interaction. The preorganized binding sites, easy derivatization and flexible three-dimensional steric structures make calixarenes ideal construction platforms for molecular design to generate fluorescente receptors. The use of calixarenes as supramolecular scaffolds for this type of architectures has been explored and the sensing abilities of resultant polymers toward metal and molecular ions established. Based on the high sensitivity shown by the non-polymeric analogue CALIX-OCP-CBZ (notshown), to toxic metal cations, we decide two extend the sensing study to polymer materials. Herein, we report the preliminar results of the chemosensing ability of a new bicyclic calix[4]arene-carbazole-polymer (CALIX-OCP-PPE-CBZ) towards the detection of toxic metals in fluid phase.