36 research outputs found
Care, Education, protection – the Associação Protectora dos Diabéticis de Portugal goes from strength to strength
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
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 400ºC, 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
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´s
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 Setúbal, 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
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 influência da composição de precursores lignocelulosicos nas propriedades adsortivas dos carvões activados produzidos
Embora existam muitas publicações sobre a produção de carvões activados muito pouco se sabe acerca da relação entre a constituição dos precursores e as características dos carvões produzidos, nomeadamente no que diz respeito a um dos precursores mais utilizados, os materiais lenhocelulósicos. Podemos também referir que uma das áreas que mais tem motivado, e que continua intensamente a motivar, os investigadores de todo o mundo é a procura de novos precursores e metodologias para a produção de carvões activados a custos mais moderados e que permitam obter materiais com características químicas e texturais controladas tendo em mente algumas aplicações específicas. A publicação de resultados tem sido contraditória e escassa no estabelecimento de uma relação entre a composição dos precursores e as características dos carvões produzidos. Assim, pretendemos com a apresentação desta comunicação contribuir para o preenchimento desta lacuna através da exposição de um estudo sistemático realizado num conjunto alargado de precusores lenhocelulósicos
Fluoxetine adsorption from aqueous solution onto activated carbons
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 ºC. 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–Vis spectrophotometer)
Biomass Novel Adsorbents for Phenol and Mercury Removal
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. Román thanks the Agencia Española de Investigación 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−, 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
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
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
Utilização de fibras de carbono activadas e carvões activados produzidos a partir de resíduos industriais como supercondensadores
No trabalho apresentado foram utilizados materiais de carbono preparados em laboratório na forma de monólitos sem o recurso a aglomerantes, designadamente fibras de carbono activadas (ACF) e carvões activados (AC) de origem distinta. As ACF (amostras F920, F932, F993) foram produzidas a partir de uma fibra acrílica comercial pela activação do dióxido de carbono a 900ºC durante tempos variados por forma a obter diferentes graus de queima, indicados na designação das amostras, os detalhes experimentais podem ser consultados na referência [4] . Por sua vez, os AC foram produzidos a partir de endocarpo de café por activação com dióxido de carbono a 700ºC (C710, C728) e a 800ºC (C823, C840,C863) e ainda pela activação do KOH (AQ62, AQ605