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Composite materials based on CaO obtained from egg shells and k-carrageenan, an anionic sulfated linear polysaccharide obtained from red seaweeds was used as an efficient, environmentally friendly heterogeneous catalyst for the transesterification of soybean oil with methanol at 60 °C. The different composite samples were produced through the dissolution of the biopolymer in an ionic liquid (IL) derived from imidazolium ion and by further addition of CaO. The samples were characterized by Attenuated Total Reflectance-Fourier Transform Infrared Spectroscopy (ATR-FTIR), Scanning Electron Microscopy (SEM) and Termogravimetry (TGA). The materials exhibit an internal structure consisting of meso and macropores which widen with the addition of small amounts of Hexamethylene diisocyanate (HMDI) that acts as a crosslinker. The composite materials present a similar thermal behaviour to k-carrageenan, without loss of stability. The catalytic activity of the prepared composite materials was evaluated in the transesterification reaction of soybean oil with methanol through catalytic runs in batch conditions. It was found that both CaO loading and polymer cross-linking affect the sorption capacity and the transport properties of the prepared catalytic materials, with best results obtained for the intermediate CaO concentration in membrane and a lower crosslinking degree.

Single-atom catalysts (SACs), consisting of metals atomically dispersed on a support, are considered as advanced materials bridging homogeneous and heterogeneous catalysis, representing the catalysis at the limit. The enhanced performance of these catalysts is due to the combination of distinct factors such as well-defined active sites, comprising metal single atoms in different coordination environments also varying its valence state and strongly interacting with the support, in this case porous carbons, maximizing then the metal efficiency in comparison with other metal surfaces consisting of metal clusters and/or metal nanoparticles. The purpose of this review is to summarize the most recent advances in terms of both synthetic strategies of producing porous carbon-derived SACs but also its application to green synthesis of highly valuable compounds, an area in which the homogeneous catalysts are classically used. Porous carbon-derived SACs emerge as a type of new and eco-friendly catalysts with great potential. Different types of carbon forms, such as multi-wall carbon nanotubes (MWCNTs), graphene and graphitic carbon nitride or even others porous carbons derived from Metal–Organic-Frameworks (MOFs) are recognized. Although it represents an area of expansion, experimentally and theoretically, much more future efforts are needed to explore them in green fine chemical synthesis.

Argan nutshells from Northern Africa were selected for a noble valorization: conversion into nanoporous carbon (ACH) through H3PO4 activation for the removal of diclofenac (DCF) and paroxetine (PARX). The performance of ACH carbon was compared to that of a commercial carbon (CC), through kinetic, equilibrium, and thermodynamic studies. An extensive characterization of the materials allowed to gain insight about the adsorption mechanisms. The biomass carbon presented a high surface area (1542 m2 g−1) and total pore volume (1.04 cm3 g−1) that corresponds mainly to mesopore volume. Despite the acidic activation, ACH surface was enriched with phenolic groups while the CC sample presented much less oxygen, mainly carbonyl-quinone groups. CC sample was also enriched with high concentrations of Si, Al, Fe, Ca, and K. CC carbon presented a higher uptake capacity of DCF (214 mg g−1) and PARX (260 mg g−1) than the ACH carbon (149 mg g−1 for DCF, and 168 mg g−1 for PARX), despite its lower surface area. DCF and PARX adsorption isotherms were best fitted to the Sips model on both carbons indicating some heterogeneous distribution of the active sites. The wide micropores developed on ACH do not provide an optimum size for adsorbates adsorption. It was established that π - π interactions and H-bonding were the main adsorption mechanisms with ACH carbon, while CC removed both molecules through interaction with the metallic elements present at the carbon and π - π interactions. In addition, electrostatic attraction of DCF by CC carbon was also an important mechanism.

This work reports the synthesis of kappa-carrageenan aerogels using different dissolution and crosslinking media in order to evaluate its effects on the textural properties of the matrixes and further on the drug loading and release performance. The different aerogel samples were produced through the dissolution of the biopolymer in water with addition of potassium salts as crosslinking agents and, in two different ionic liquids (ILs) derived from imidazolium ion, being further dried with supercritical CO2. The samples were characterized by Attenuated Total Reflectance-Fourier Transform Infrared Spectroscopy (ATR-FTIR), Scanning Electron Microscopy (SEM), Nitrogen Adsorption-Desorption Analysis, Thermogravimetry (TGA) and Differential Scanning Calorimetry (DSC). The synthesized samples presented surface areas similar to the carrageenan aerogels being their structure constituted mainly by meso and macropores. The absence of ionic liquid in samples was demonstrated by DSC analysis and was corroborated by the cytotoxicity assays which revealed that cellular viability in Caco-2 cells was preserved. Tetracycline was used as a model drug and loaded in two of the prepared aerogels samples. The release experiments were performed with the composites to test in vitro drug release at physiologic pH. With a higher macroporosity, the kappa-carrageenan aerogel prepared by dissolution into ionic liquid showed a higher loading capacity than the one prepared by dissolution into water and a slightly higher release rate. The matrixes were considered to present a good potential to be used as biocompatible carriers on drug controlled delivery.

Locust bean gum (LBG) is a natural polymer that belongs to the increasingly attractive biodegradable polymers derived from natural sources. This polymer possesses a number of appealing features such as non-toxicity that confer it a high potential for the use in fields such as pharmacy and food industries. In this work, three methylimidazolium-based ionic liquids (ILs) were used as alternative media in the preparation of biocompatible LBG gel matrices. The process consists of dissolving the biomaterial in a selected IL followed by a multi-step solvent exchange using a mixture of water and ethanol. The final gel (internal surface areas ranging from 60 to 180 m2 g−1) is then dried using a semi-continuous high pressure CO2 extraction process. To the best of our knowledge this is the first time that LBG mesoporous gel matrices are reported using this efficient sustainable method.

The work reports the impregnation of naproxen into locust bean gum mesoporous matrixes with different textural properties. The matrixes were prepared through the dissolution of the biopolymer in water and in two ionic liquids (ILs): [bmim][Cl] and [C2OHmim][Cl] and dried with scCO2. The poor water-soluble pharmaceutical drug naproxen was loaded into the matrixes and the composites were characterized by attenuated total reflectance-Fourier transform infrared spectroscopy and by differential scanning calorimetry; the results were compared with neat ILs and drug. The naproxen release from the matrixes was attempted at pH 7.4. Sustained release of naproxen in the different composites occurs, and consequently the naproxen release has lower rates compared with neat crystalline naproxen dissolution. Nevertheless, it was possible to observe small differences on release profiles for the studied composites. The higher release rate was observed for the composite where [bmim][Cl] was used as solvent, for which the calorimetric analysis revealed full amorphization of the incorporated drug. Cytotoxicity assays reveal that cellular viability in Caco-2 cells is preserved. This fact allied with the biocompatibility of locust bean gum allow for the composites potential application as naproxen controlled/sustained delivery systems with higher drug bioavailability achieved through naproxen amorphization.

In this work polyelectrolyte multilayers (PEMs) produced through the layer-by-layer (LbL) method were used for the in situ synthesis of Au and Ag metal nanoparticles on the surface of float glass in order to colour it. The samples were characterized by UV–Vis absorption spectroscopy, Scanning Electron Microscopy (SEM), Rutherford Backscattering Spectrometry (RBS) and Particle Induced X-Ray Emission (PIXE). The use of temperatures slightly above the glass transition temperature (Tg) during the thermal treatment allowed the fixing of the nanoparticles, colouring the glass surface. Pink and blue colours were obtained from Au nanoparticles, yellow colour from Ag, and orange from a mixture of both Au nanoparticles and Ag nanoparticles. Variables such as the pH value during film assembly, the number of layers used to form the PEMs, the time duration of thermal treatment, and the presence or absence of Sn in the surfaces of float glass, all influence its colouration. Thermal treatments shorter than 1 h already promote the diffusion of Ag into the glass and therefore fix it, while longer times are necessary to fix the Au metal. The Ag colour intensity in the glass is easily controlled through the number of layers while in the case of Au this variable influences not only the colour intensity but also the tone.

The [bmim][BF4] ionic liquid effect on gold nanoparticles formation in silica sol–gel materials is studied in order to produce gel-derived glasses with optical properties. The characteristic red color from gold nanoparticles is observed for transparent glass monoliths obtained sintering, between 365 and 425 °C, a silica sol–gel precursor containing HAuCl4·3H2O and [bmim][BF4], under normal atmospheric conditions. The effect of sintering the ionogel at different temperatures (Tsint) or times (tsint) on the optical properties, shape, size, and distribution of gold nanoparticles is discussed. Presence of the gold particles is observed using transmission electron microscopy images followed by energy dispersive X-ray spectroscopy analysis. The thermal decomposition of [bmim][BF4] in the ionogel is investigate using calorimetric and spectroscopic techniques, and by analysis of volatile compounds released by the sol–gel material during sintering. With these results a mechanism for the formation of the gold nanoparticles is proposed, where a first ionic liquid degradation step provides the reductive environment that enables the gold nanoparticles production at the range of temperatures between 350 and 425 °C. Upon sintering the synthesized materials the ionic liquid acts as a sacrificial additive and the ionic liquid thermal decomposition products enables the formation of gold nanoparticles in the sol–gel matrix.

In this work, coloured glasses were produced based on the synthesis of gold and silver nanoparticles by the sol–gel process having in mind their application in art works. Gold and silver were used separately or as a mixture by varying the mole fractions in order to get a range of colours from yellow to red. The gold and silver nanoparticles were prepared by the reduction of tetrachloroauric acid and silver nitrate with sodium citrate in aqueous solutions which were further introduced in the sol–gel system. Attention was focused on the thermal treatment of the sol–gel samples. Different temperatures were used in order to determine their influence on the obtained colour. The glasses were characterized by UV–Vis absorption spectroscopy and the size of the nanoparticles was examined by transmission electron microscopy (TEM). The range of colours mentioned above is obtained either by preparing nanoparticles of each metal and mixing them or by preparing nanoparticles from solutions containing initially ions of both metals. In the former case, two surface plasmon resonance (SPR) bands were observed for temperatures below 200 °C while higher temperatures promote the formation of alloys between the Ag and Au nanoparticles. In the latter case, only one SPR band is observed and the nanoparticle size distribution is narrower. The results were explained by nanoparticle aggregation promoted by temperature. Glasses containing only Ag did not present the typical yellow colour above 300 °C but it was shown that the colour could be stabilized if Au was added in small amounts (Au/Ag molar ratio 0.1).

The formation of Eu(III) nanoparticles in borosilicate sol−gels and the glass formation heat treatment effect on those particles were studied using luminescence techniques. The presence of the particles was observed using transmission electron microscopy (TEM) images followed by analysis with energy dispersive X-ray spectroscopy (EDS). These experiments showed the presence of particles with a large quantity of europium and chlorine and only small amounts of oxygen with sizes ranging from 30 to 100 nm. Heat treatment at 400, 600, and 800 °C lead to glass samples in which those particles were no longer observed. Steady-state and time-resolved luminescence techniques allowed a detailed study of Eu(III) photophysics in sol−gel and glass samples. In sol−gel matrices, the 5D0 → 7F0 transition is very weak, hinting at Eu(III) species experiencing a rather symmetric crystal field. The 5D0 → 7F2 transition intensity is not very strong, which according to a Judd−Ofelt analysis indicates low interaction with the ani...

The selenium content in fruit and vegetable samples from two regions in Portugal were analysed using hydride generation atomic fluorescence spectrometry (HG-AFS) and radiochemical nuclear activation analysis (RNAA) – two analytical methods with very low limits of detection. The lower detection limits of HG-AFS, 3 μg kg −1 and 8 μg kg −1 (according to conditions used for digestion), and for RNAA, 10 μg kg −1 , meant that it was possible to determine selenium in samples previously analysed using the replicate sample instrumental nuclear activation analysis (RSINAA) with a higher detection limit associated. The results obtained with the HG-AFS method were similar to those obtained using either RNAA or RSINAA, although in the case of RSINAA significant differences were found in three samples. The good accuracy and increased sample throughput, together with the relatively lower equipment and operating costs make HG-AFS the optimum of the three methods for determining trace amounts of selenium. Values obtained by HG-AFS were from 0.03 μg in tomato to 3.1 μg in cabbage (100 g fresh weight). Based on our results, the contribution of the analysed vegetables and fruits to the daily selenium intake was 1.80 μg per person per day for the Portuguese population.

Selenium daily intake was determined for two small groups of the Portuguese population, based on the analysis of duplicate diet portions. The total amount of food ingested during a day was collected for 18 workers of the Technological and Nuclear Institute (ITN-Sacavem) and for 6 females of Reguengos de Monsaraz, a small town in the south-eastern hinterland. The average selenium daily intake was 43 ± 20 and 32 ± 13 μg per person, respectively, both lower than the Recommended Dietary Allowance (RDA) of 55 μg day−1. Selenium in diet samples was determined by replicate sample neutron activation analysis (RSINAA). The method was considered accurate for the selenium determination.

The replicate sample instrumental neutron activation method was optimized and used for the deter- mination of selenium in foodstuffs. The method was reli- able, yielding accurate results. Lower detections limits were obtained after each successive irradiation. Different irradiation conditions were used depending on the type of sample. For samples with higher selenium contents (meat, fish, eggs), the measured selenium in the first replicate is in all cases larger than the detection limit, but a better accu- racy was obtained with a larger number of replicates (2-3 replicates). For samples with extremely low selenium contents (vegetable samples), at least seven replicates were necessary to obtain a concentration value two times larger than the detection limit.

This study deals with Particle Matter (PM) levels in the metropolitan area of Lisbon and shows that EU directive is exceeded in a systematic way, mainly due to the inner city traffic. Results show that it is important to develop an epidemiological study in Lisbon to find a possible association between PM levels, sources and morbidity. Some important issues related with a monitor's representation of regional, sub-regional, and local air pollution exposures to the population in the metropolitan area are highlighted. PM2.5 and PM10 total mass concentration measured in several places located in both centre of Lisbon and the outskirts are quite well correlated, mainly considering that two measuring methodologies (automatic and gravimetric) were used and areas with different classifications (urban and suburban) were analysed. However, the results imply that a source-oriented evaluation of PM health effects needs to take into account the uncertainty associated with spatial representativity of the species measured at a single sampling station. Temporal correlation across sampling stations, within relatively short separation distances, varied considerably for some important elements (Zn, Sb, Cu, As and Br), indicating that the precision of population exposure estimates for specific elements can vary depending on the species.

In the present study, selenium contents for some selected food items commonly consumed in Portugal are presented. Food items, i.e., meat, fish, eggs, dairy products, cereals, fruits and vegetables were sampled from two representative markets of two different regions of Portugal territory. The selenium concentrations in the various food items have been determined by using nuclear activation analysis (NAA) in both versions instrumental (INAA) and replicate sample (RSINAA) through the short-lived nuclide 77mSe that features a half-life time of 17.5 s. The highest values were found for meat, fish and eggs (87.6–737 μg kg−1); lower values were obtained for vegetables and fruits (1.7–24.9 μg kg−1).

Vegetables play an important role in national diets, as a side dish to many a main-course fare the whole year round, and, especially in what concerns raw lettuce and tomato, with a higher seasonal rate of consumption during summer months, as associated to the traditional charcoal-grilled sardines. In March 2004, lettuces, tomatoes, carrots and cabbages of Portuguese origin (except for the carrots from one site) were purchased from large commercial areas or central markets of two central and southern regional hubs, respectively Coimbra and Evora. Even if from different growers, all vegetables had come from horticultural plots in the same general area of western Portugal, north of Lisboa. For lettuce plants, the inner leaves were separated from the external ones and processed as different samples for further analysis. In this work, the reactor and detector parameters were re-evaluated for the new IAEA k0-INAA software. Quality assessment was obtained through analysis of IAEA-359 (cabbage material) and BCR-679 (Bowen's kale). Traces of hazardous elements—namely, antimony, arsenic and bromine—could be found throughout, and, for lettuce samples, the overall results indicate that outer leaves feature higher concentrations than inner ones. Interestingly enough, vegetables from Coimbra and Evora appeared to differ from each other in their elemental levels, even if originally grown at relatively close range. Concentrations of trace elements are compared to available data from other countries’ cultivars.

Selenium contents in the Portuguese (mainland) territory, resulting from a few environmental studies held since 1990 using lichens, vascular plants, soils and air particulate matter (APM), are presented and discussed herein. Values for Se in soils, epiphytic lichens and higher plants are within the typical ranges found in the literature. Compared to vascular plants, lichens display higher contents at the same locations. In what concerns Se in airborne particulates, all surveyed sites show values that are typical of urban areas. In two of such sites – Monchique and Carregado – Se concentrations in transplanted lichen thalli of the Parmelia genus (mostly, Parmelia sulcata Taylor) were compared to the results obtained from airborne matter, and a good correlation was found for the corresponding data-sets at either location. Other than the degree of association, it is especially noteworthy that the lichen transplants appear to accumulate much more Se at Monchique (a remote, rather clean site) than at Carregado (in the immediate vicinity of an oil-fired, power plant), even if its amount in the atmosphere is lower at the former location.

Selenium is determined by instrumental neutron activation analysis (INAA), based on measurement of the long-lived 75Se nuclide. In the urban and industrialized areas of Portugal selenium contents have been found of the order of of 0.5-1 ng/m3 in PM10 and PM2.5, according to the data collected since 1994. From November 12, 2001 and for not more than 3 months, the Se contents in PM10 and PM2.5 increased by a factor of 1000 in the northern area of Lisbon. More than other nutrients, selenium illustrates the dichotomy between essentiality and toxicity. There is no legislation on Se for ambient air and on indoor ambient point threshold limit values (US and Germany legislation), were 100 times higher than the abnormal values found that winter. The increase was also visible for mercury although not to such an extent. Attempts were made to understand the trend, going into a study of the emission sources located in the area using both INAA and PIXE. It was concluded that the observation occurred due to abnormal meteorological wind direction, which pushed the pollutants towards the populated area, when usually they flow into the Tagus estuary.

Other than their inherent accuracy, analytical robustness and nondestructive features, instrumental neutron activation analysis (INAA) and particle-induced X-ray emission (PIXE) are both multi-elemental techniques that complement – and partially overlap – each other with respect to a vast majority of elements of interest in environmental studies and life sciences at large. Analytical accuracy notwithstanding, INAA and PIXE ask for different sample-preparation procedures and rely on dissimilar energy-related profiles, which can lead to some divergence in their operational outputs. Especially interesting are the elements determined by either technique, in that they can provide what one might call an index of intrinsic reliability as to an elemental pool. This paper presents an evaluation of the relative performance of INAA and PIXE on measurements in atmospheric biomonitors, namely epiphytic lichens of the Parmelia genus. The study is based upon 4 elements – Fe, Mn, Rb (customary crustal references) and K (an indicator of physiological status) – in lichen samples from 58 sites in mainland Portugal. Distribution-free statistics – rank-order correlations and enhanced-sign tests – were used for checking the degree of association between concentration patterns (variables) and any significant differences between individual values (variates), respectively. The results show that (i) for all elements, the area-wide patterns by either technique display similar trends; and (ii) for all elements but rubidium, no statistically sound evidence for relative bias – consistently higher or lower values by one technique – could be found. As far as this investigation goes, the techniques may be used interchangeably for determining Fe, K and Mn in Parmelia spp. samples.

As part of a contract for air-quality monitoring in the neighbourhood of an urban waste incinerator, measurements of PM10 and PM2.5 are being routinely evaluated at three sampling locations. Samples are collected for 24 h at the weekend and a working day, using a Gent collector (separates two fractions: PM2.5 and PM2.5–10). Filters are analysed by instrumental neutron activation analysis (INAA) and proton induced X-ray emission (PIXE). As and Hg are determined by INAA, and Ni and Pb are obtained by PIXE. Considering a 24 h/week sampling basis, As and Pb concentrations in PM2.5 show a seasonal trend with higher concentrations during autumn and winter; Ni levels are practically constant the whole year round, with a few episodes; and Hg concentrations tend to increase from October to September. A significant correlation appears for arsenic and lead, and arsenic and nickel.

At ITN, PM10 and PM2.5 aerosols were collected on Nuclepore® polycarbonate filters of 47 mm diameter, using Gent samplers at 15–17 l/min air flux. Filters were analyzed by INAA and PIXE. The availability of certified filters was very scarce, viz.: (1) fly ash embedded in a methyl cellulose 47 mm foil 10 µm thick, BCR CRM128, (2) particle-size reduced air particulate matter (APM) to simulate PM2.5 aerosol matter deposited on a 47 mm polycarbonate filter membrane, NIST SRM 2783. The high price and scarcity of APM standards did not permit their frequent use for analytical quality control. At ITN, to control the filter results' accuracy, the chemical elements potassium, iron and zinc, determined by both techniques, were systematically compared. After a few improvements introduced in INAA, this technique was now considered at ITN as the reference technique in air particulate measurements. Comparison of INAA to PIXE was discussed. Compared to previously reported situation it was concluded that the results were in better agreement for iron and zinc, and potassium values were still biased to the same extent as before.

This paper describes concentration amounts of arsenic (As), particulate mercury (Hg), nickel (Ni) and lead (Pb) in PM(10) and PM(2.5), collected since 1993 by the Technological and Nuclear Institute (ITN) at different locations in mainland Portugal, featuring urban, industrial and rural environments, and a control as well. Most results were obtained in the vicinity of coal- and oil-fired power plants. Airborne mass concentrations were determined by gravimetry. As and Hg concentrations were obtained through instrumental neutron activation analysis (INAA), and Ni and Pb concentrations through proton-induced X-ray emission (PIXE). Comparison with the EU (European Union) and the US EPA (United States Environmental Protection Agency) directives for Ambient Air has been carried out, even though the sampling protocols herein--set within the framework of ITN's RD projects and/or monitoring contracts--were not consistent with the former regulations. Taking this into account, 1) the EU daily limit for PM(10) was exceeded a few times in all sites except the control, even if the number of times was still inferior to the allowed one; 2) the EU annual mean for PM(10) was exceeded at one site; 3) the EPA daily limit for PM(2.5) was exceeded one time at three sites; 4) the EPA annual mean for PM(2.5) was exceeded at most sites; 5) the inner-Lisbon site approached or exceeded the legislated PMs; 6) Pb levels stayed far below the EU limit value; and 7) concentrations of As, Ni and Hg were also far less than the reference values adopted by EU. In every location, Ni appeared more concentrated in PM(2.5) than in coarser particles, and its levels were not that different from site to site, excluding the control. The highest As and Hg concentrations were found in the neighbourhood of the coal-fired, utility power plants. The results may be viewed as a "worst-case scenario" of atmospheric pollution, since they have been obtained in busy urban-industrial areas and/or near major power-generation and waste-incineration facilities.

The authors trace the progress among courts, legislatures, and professional and advisory bodies toward the acceptance of legal standards that define death by reference to neurologic criteria. Competing legal formulations and medical proposals are examined, and those standards ultimately adopted in various jurisdictions are set forth.