ISEL - Eng. Quim. Biol. - Posters
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- Study of antioxidant and antitumoral activity of cork processing wastewaters components fractionated by ultrafiltration membranesPublication . Gomes, Luís; Borges, C.; Serralheiro, M.L.M.; Pacheco, Rita; Minhalma, MiguelCork processing wastewater present a severe environmental problem due to its high content in organic matter, such as sugars and non-biodegradable compounds like polyphenols (PPs), namely tannins. In this work, the assessment of the biological activity and identification of valuable polyphenolic compounds was envisaged. These compounds were obtained using membrane technology, leading to the valorisation of the wastewater components and simultaneously leading to the decrease of its pollutant content.
- 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.
- On the nature of carbon nanodots photoluminescence from olive wastesPublication . Costa, Alexandra; Prata, José VirgílioA great structural diversity of carbon nanodots (CNDs) have been obtained in the last ten years by a variety of methods, carbon sources, additives and/or passivating agents, and operation parameters. Not unexpectedly, many properties diverge owing to disparate structural features. The photoluminescence (PL) is one of them. A vast literature is already available on this topic, with findings that are somehow apparently contradictory. At least three possible origins of PL in CNDs have been identified: i) quantum confinement effects associated with the sp2 domains of the carbon core; ii) surface states lying in the edges of sp2 carbogenic core; iii) molecular states originating from molecular species embedded or covalently linked to the carbon matrix.
- 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.
- 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.
- Utilização de biomassa liquefeita na produção eletroquímica de gás de síntesePublication . Gonçalves, Ana Luísa; Guerra, Luís Filipe; Rodrigues, J.; Puna, Jaime; Gomes, João; Bordado, JoãoO presente trabalho de investigação visa, precisamente, a utilização de energias renováveis (solar ou eólica) no processo de eletrólise alcalina da água tendo como objetivo a produção de gás de síntese, com recurso a biomassa liquefeita como fonte de carbono, para uma posterior produção de biocombustíveis sintéticos.
- Novel bicyclic fluorescent calix[4]arene-based sensors for toxic metalsPublication . Costa, Alexandra; Fialho, Carina B.; Barata, Patrícia; Prata, José VirgílioCalix[4]arene has been widely exploited as the basic molecular framework for many fluorescent chemosensors in the construction of selective binding sites given its structural rigidity (particularly important when the recognition and reporting events are to be undertaken in fluid phase), various conformations, and facile introduction of fluorophores. Exploring the inherent capabilities of certain fluorescent calixarene scaffolds for establishing strong host:guest interactions, several sensing materials have been recently developed by us [1]. In the same line of research new bicyclic calix[4]arene-based fluorescent chemosensors containing amides as coordination sites (ionophore) and carbazole segments as fluorescent signaling moieties (CALIX-AMD-CBZ) are being developed and that are expected to have high ability toward the detection of metallic cations in solution. However its complex synthesis and characterization has led to the use of a similar compound based on narrow rim 1,3-oxacyclophane tethered calix[4]arene derivatives integrating the same fluorescent segments (CALIX-OCP-2-CBZ) [2] as fluorophore in the present communication. Herein we report the most significant photophysical properties and sensory capabilities of CALIX-OCP-2-CBZ towards divalent ions (Cd2+, Cu2+, Hg2+, Pb2+) by fluorescence spectroscopy in fluid phase.
- 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.
- 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).