36 research outputs found

    Care, Education, protection ‚Äď the Associa√ß√£o Protectora dos Diab√©ticis de Portugal goes from strength to strength

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    The Portuguese Diabetes Association is the world’s oldest diabetes association and a senior Member Association of the International Diabetes Federation. From the moment it was founded, early in the 20th century, to the present day, the Associação has been driven by a single overarching objective: to improve the quality of life of people with diabetes. Involved nationally in diabetes advocacy and the provision of education, as well as the delivery of care, APDP has become a key player in the healthcare arena in Portugal and its activities reach many thousands of people with diabetes

    Production and characterization of activated carbons made from sunflower stems

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    Activated carbons (ACs) are artificial materials, prepared from natural or synthetic precursors that are worldwide extensively used. The ACs main characteristics are the noticeable adsorption capabilities provided by the highly developed porous structure and the rich surface chemistry. Because of their versatility and properties the final material can be tailored to have specific properties suitable for a wide range of applications such as medical uses, gas storage, removal of pollutants and odours, gas separation and purification as well as in catalysis. With the increase of activated carbon demand, one of the main challenges lies in the attempt to find new precursors, which are cheap and accessible with good valorisation potential, like industrial and agricultural residues. In the present work we report the production of ACs from sunflower stems, an agricultural by-product, through a physical activation process by CO2 and H2O, using a single step carbonisation at 400¬ļC, which as far as it came to our knowledge was never made for this precursor

    Decolourisation of a pulp mill effluent using commercial activated carbons

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    The decolourisation of industry effluents is a challenging and fundamental task related to pollution control, mainly in pulp mill and textile industries. The dark colour of the pulp mill effluent, depending on the river characteristics, can lead to the reduction of the light penetration into the aquatic environment with the consequent decrease of photosynthesis and aquatic life destruction. Also, the lignocelulosic material deposited on the margins and river bed can lead to a large depletion of the dissolved oxygen with the creation of anaerobic conditions that can give rise to the death of aquatic organisms (Ali, 2001). The chemical composition of the pulp mill effluent (referred as effluent) is very complex. Nevertheless, we can say that the lignin and tannin compounds are the main causes for the effluent¬īs dark brown colour. Among these compounds we can find hidroxyphenyl, siringyl and guaiacyl complexes (Mohan, 1997). These compounds are chemically stable, resistant to biodegradation and extremely difficult to separate by most methods in cost effective processes, such as membrane adsorption (Mutlu, 2002), cationic coagulants, ultrafiltration (Mutlu, 2002) and chemical oxidation (Malik, 2004). One of the most promising methods is the use of activated carbons for the removal of the effluent colour. In this work the use of 5 commercial activated samples with different shapes, origins and characteristics were tested for the decolourisation of a pulp mill effluent collected directly on the effluent discharge of a plant situated in Set√ļbal, Portugal, property of Portucel. The colour adsorption was done using batch and dynamic trials

    Activated carbon fibres prepared from kenaf: Influence of the experimental consditions on the morphology and textural properties

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    Porous materials are usually heterogeneous both structurally and energetically. Activated carbon fibres (ACFs) are relatively novel fibrous adsorbents produced for example from pith, cellulose, lignocellulose, phenol resin and polyacrylonityile (Peebles, 1995; Ryu, 1999). ACFs show important advantages with respect to conventional activated carbons. Among these advantages it is worth noting their high adsorption capacity and easiness to handle. Their main inconvenience lays on the difficulty of choosing adequate activating agents and activation conditions that are required in order to maintain the fibrous morphology. The adsorption capacity of ACFs depends on many factors, such as raw materials, activation process, pore structure and surface functionalities (Suffet, 1981; Park, 1999). Surface roughness is an important factor that influences the adsorption properties of an activated carbon. Fractal dimension is a measure of roughness of a surface. The use of the fractal concept is becoming very popular as a tool to characterize the texture of complex materials, such as porous solids. The fractal properties of these porous systems were determined by means of several techniques such as gas adsorption, mercury porosimetry and Small-Angle X-Ray Scattering (SAXS and SANS). Kenaf is an herbaceous annual plant that belongs to the family of Malvaceae. Kenaf possesses both, long and short fibre. The aim of this work is to study the influence of the preparation conditions on the fractal dimension and porous texture of ACFs prepared from long fibres of kenaf by physical activation using carbon dioxide as activating agent

    Estudo da influ√™ncia da composi√ß√£o de precursores lignocelulosicos nas propriedades adsortivas dos carv√Ķes activados produzidos

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    Embora existam muitas publica√ß√Ķes sobre a produ√ß√£o de carv√Ķes activados muito pouco se sabe acerca da rela√ß√£o entre a constitui√ß√£o dos precursores e as caracter√≠sticas dos carv√Ķes produzidos, nomeadamente no que diz respeito a um dos precursores mais utilizados, os materiais lenhocelul√≥sicos. Podemos tamb√©m referir que uma das √°reas que mais tem motivado, e que continua intensamente a motivar, os investigadores de todo o mundo √© a procura de novos precursores e metodologias para a produ√ß√£o de carv√Ķes activados a custos mais moderados e que permitam obter materiais com caracter√≠sticas qu√≠micas e texturais controladas tendo em mente algumas aplica√ß√Ķes espec√≠ficas. A publica√ß√£o de resultados tem sido contradit√≥ria e escassa no estabelecimento de uma rela√ß√£o entre a composi√ß√£o dos precursores e as caracter√≠sticas dos carv√Ķes produzidos. Assim, pretendemos com a apresenta√ß√£o desta comunica√ß√£o contribuir para o preenchimento desta lacuna atrav√©s da exposi√ß√£o de um estudo sistem√°tico realizado num conjunto alargado de precusores lenhocelul√≥sicos

    Fluoxetine adsorption from aqueous solution onto activated carbons

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    With these premises, this work aimed to prepare ACs from almond tree pruning by physical activation processes with steam and carbon dioxide, under different temperature conditions. Selected samples were impregnated with triethylenediamine (TEDA, 5%wt.) by sublimation. The ACs characterization was made by N2 adsorption at 77 K (AUTOSORB-1, Quantachrome), mercury porosimetry (AUTOPORE 4900 IV, Micromeritics), helium stereopycnometry (Quantachrome), FT-IR spectroscopy (Perkin Elmer model Paragon 1000PC) and pzc determination. The fluoxetine adsorption was studied under neutral pH at 25 ¬ļC. Stock solutions of fluoxetine HCl (0.5 and 1 gL-1) were prepared in deionized water with variable amounts of ACs (0.010 and 0.200 g), maintaining the contact during 420 min. The determination of fluoxetine HCl was done by ultraviolet absorption at 274 nm (Perkin Elmer Lambda 850 Uv‚ÄďVis spectrophotometer)

    Biomass Novel Adsorbents for Phenol and Mercury Removal

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    Funding Information: The authors are thankful to FCT (Portugal), COMPETE, QREN, and EU (European Regional Development Fund, FEDER) for financial support through Project FCOMP-01-0124-FEDER-007142. S. Rom√°n thanks the Agencia Espa√Īola de Investigaci√≥n for the financial help through project PID2020-116144RB-I00/AEI/10.13039/501100011033.This paper reports the use of activated carbons made from novel agriculture and industrial wastes, namely sunflower, vine shoots, and coffee endocarp, to remove two high-priority contaminants: phenol and mercury species (under different forms) from aqueous solutions. The activated carbons were used as prepared and also modified with nitric acid and triethylenediamine in order to explore additional adsorption mechanisms. The results showed an interesting potential of the materials to be used for water decontamination as indicated by the mercury uptake up to 1104 mg/g for Hg2+, 771 mg/g for [HgCl4]2‚ąí, 966 mg/g for HgCl2 and the maximum phenol adsorption capacity of 190 mg/g. The modification with triethylenediamine led to a significant increase in the phenol and mercury adsorption reaching an increment of 85% for phenol and 250% for Hg2+.publishersversionpublishe

    IN VITRO AND IN VIVO REMOVAL OF ORAL ANTIDIABETIC AGENTS (METFORMIN) USING ACTIVATED CARBONS

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    Diabetes is the most worldwide common chronic disease, according the International Diabetes Federation [1], more than 32 million citizens living in the European Union have diabetes, representing nearly 10% of the population, to which we should add equal number of people suffering from impaired glucose tolerance. Diabetes prevalence is growing at alarming rate worldwide, being of particular relevance the type 2 diabetes. Nowadays 285 million people worldwide live with diabetes and it is expected that this numbers will increase by 20% until 2030 due to obesity and the ageing of the population [1]. This growth leads to an increasing consumption of drugs such as oral antidiabetics. Metformin is one of the active principles most commonly used for this purpose being among the pharmaceuticals with the highest production numbers worldwide to treat type 2 diabetes because is cheap, has high level of tolerance and when used in the prescribed dosage is very secure with minimal side effects. However, in case of overdose of metformin upon a ingestion of more than 10 times the prescribed dosage, accidentally or on propose, lactic acidosis and low blood pressure can occur. Overdoses with metformin are relatively uncommon, but may have serious consequences, if medical attention is not given on time, it may lead to coma and ultimately death Because of its spread use another problem must be taken into consideration, which needs to be addressed, the occurrence of metformin residues in sewage and surface waters due to improper discharge of the non-used tablets to regular garbage [2]. This situation is becoming a serious problem of environmental pollution and public health. This paper reports the use of activated carbon produced from biomass for the removal of metformin in 2 different settings. On one hand, from aqueous solutions and, in another hand, from simulated biological fluids (gastric and intestinal) conjugated with in vivo testing

    Production and characterisation of activated carbons made from coffee industry residues

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    Porous materials are usually heterogeneous both structurally and energetically. Activated carbon fibres (ACFs) are relatively novel fibrous adsorbents produced for example from pith, cellulose, lignocellulose, phenol resin and polyacrylonityile (Peebles, 1995; Ryu, 1999). ACFs show important advantages with respect to conventional activated carbons. Among these advantages it is worth noting their high adsorption capacity and easiness to handle. Their main inconvenience lays on the difficulty of choosing adequate activating agents and activation conditions that are required in order to maintain the fibrous morphology. The adsorption capacity of ACFs depends on many factors, such as raw materials, activation process, pore structure and surface functionalities (Suffet, 1981; Park, 1999). Surface roughness is an important factor that influences the adsorption properties of an activated carbon. Fractal dimension is a measure of roughness of a surface. The use of the fractal concept is becoming very popular as a tool to characterize the texture of complex materials, such as porous solids. The fractal properties of these porous systems were determined by means of several techniques such as gas adsorption, mercury porosimetry and Small-Angle X-Ray Scattering (SAXS and SANS). Kenaf is an herbaceous annual plant that belongs to the family of Malvaceae. Kenaf possesses both, long and short fibre. The aim of this work is to study the influence of the preparation conditions on the fractal dimension and porous texture of ACFs prepared from long fibres of kenaf by physical activation using carbon dioxide as activating agent. * Autho

    Utiliza√ß√£o de fibras de carbono activadas e carv√Ķes activados produzidos a partir de res√≠duos industriais como supercondensadores

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    No trabalho apresentado foram utilizados materiais de carbono preparados em laborat√≥rio na forma de mon√≥litos sem o recurso a aglomerantes, designadamente fibras de carbono activadas (ACF) e carv√Ķes activados (AC) de origem distinta. As ACF (amostras F920, F932, F993) foram produzidas a partir de uma fibra acr√≠lica comercial pela activa√ß√£o do di√≥xido de carbono a 900¬ļC durante tempos variados por forma a obter diferentes graus de queima, indicados na designa√ß√£o das amostras, os detalhes experimentais podem ser consultados na refer√™ncia [4] . Por sua vez, os AC foram produzidos a partir de endocarpo de caf√© por activa√ß√£o com di√≥xido de carbono a 700¬ļC (C710, C728) e a 800¬ļC (C823, C840,C863) e ainda pela activa√ß√£o do KOH (AQ62, AQ605
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