Influence of mordants in the colour of natural dyes: theoretical predictions and experimental results

Arraiolos tapestries are probably one of the richest artistic Portuguese expressions in terms of textile production and a cultural heritage that urges to preserve. The richness of colours displayed by some of the Arraiolos tapestries denotes the likely use of a wide variety of dyes. The different light-fastness of dyes combined with the use of different types of mordants can also explain the appearance of pale shades and fading in some tapestries due to different molecule interactions with the support fibres. The work we present is part of a major project (experimental and theoretical) that envisages the identification of the dyes and mordants used throughout the ages in the production of Arraiolos tapestries and the establishment of the major factors (like mordant, humidity and light) that are responsible for the colour and fading of the natural dyes as well as for the degradation of the fibres. It is well known that the colour of a dye depends on the type of mordant used, due to the formation of metal complexes that cause a change in the molecular orbitals energies and hence a shift in UV/Vis absorption bands. The electronic structure and transitions in the visible spectra of some dyes and mordants identified on Arraiolos rugs were predicted by the ZINDO-INDO/S semi-empirical molecular orbital method [1,2] in order to identify the origin of the colours and characterize the influence of metal coordination on colour modifications. The molecular geometry of each dye-mordant complex was optimized at DFT level using the Gaussian03 package [3] and a simulation of the UV/Vis absorption spectrum was calculated using ZINDO. Another important outcome of this study was the determination of the chromophore properties of fragment molecules produced by the dyes degradation processes that enabled the evaluation of the colour changes of the dyes and subsequent fading. Wool fibres were dyed with previously identified natural dyes and mordants and the colour parameters and the spectra were determined using a UV-Vis portable spectrometer. These parameters were compared with the results from the theoretical predictions

Using clay materials to remove pharmaceuticals from waters

Pharmaceutical active compounds (PhACs) have an important role in the treatment and prevention of disease in both human and animals. Ingested drugs are only partially absorbed by the organisms and studies have shown that the excreted compounds are only partially removed in the sewage treatment plants (STPs) [1]. Contaminated effluents are being released from the STPs and trace amounts of PhACs have been detected in wastewaters, surface and groundwaters worldwide [1]. Acidic pharmaceuticals like diclofenac, ibuprofen and clofibric acid are some of the most frequently detected compounds [1]. The concentrations detected are low (ng/L - μg/L) but, due to the very nature of these compounds, studies have shown damaging effects on the aquatic ecosystems [1]. Several different processed natural materials can be used as filter media in water and wastewater treatment systems. Some of these materials can additionally present functions which extend beyond the simple process of filtration. Their surface areas can constitute a support for microbial population growth in biofilters as well as support matrix for the development of macrophytes in sub-surface flow constructed wetland systems (SSF-CWS) [2] which are increasingly being used in sewage tertiary treatment. The efficiency of these biological systems in the removal of xenobiotics can be significantly enhanced by a greater capability of the support matrix to retain contaminants by sorption phenomena, ionic exchange or other physico-chemical processes [2]. The aim of the present work was to evaluate the efficiency of two different materials namely, Light Expanded Clay Aggregates [LECA] (in two different particle sizes) and sand, for the removal from water of three acidic PhACs, clofibric acid, diclofenac and ibuprofen. In addition, relationships were established between the compounds removal efficiencies and the physico-chemical properties of each material. A series of batch essays were carried out to study the sorption capacities of the different materials for the 3 chemical compounds. The influence of some experimental conditions, such as the contact time, the initial PhACs concentrations (1 mg/L up to 50 mg/L) and LECA particle size, were investigated. The media were sterilized before use in order to minimize any microbial development on the matrix and experiments were conducted in the dark to avoid any photocatalytic degradation reactions. The mineralogical composition of the materials was determined by X-ray diffraction and some physico-chemical properties were characterized. Samples of the contaminants’ aqueous solutions were collected over a range of contact times with the support matrix and the remaining concentrations in solution were determined by UV/Vis spectrophotometry. The results show that LECA has a good sorption capacity for acidic compounds. In contrast, sand does not exhibit any sorption capacity for any of the compounds tested. Not surprisingly, LECA with smaller particle sizes show higher efficiencies that larger grade LECA, due to a larger available surface area. However, the use of these smaller particle media at upper scales may present problems with hydraulic conductivities. From the results obtained, it can be concluded that expanded clay presents important advantages as a CWS support matrix or as a filter medium, because it has a good sorption capacity, a pH buffer capacity and an excellent control of hydraulic permeability. On the other hand, sand does not exhibit any sorption capacity that might enhance the performance of filters and CWS in the treatment of water contaminated with this type of contaminants

Removing pharmaceutical residues from contaminated wastewaters using expanded clay aggregates

Pharmaceutical compounds (PhCs) are ingested in large quantities by humans in treatment and prevention of disease, but they are only partially absorbed by the organisms being excreted together with their metabolites. The sewage treatment plants (STP) are only able to partially remove some of these compounds and, despite the low concentrations present in the wastewaters (ng-μg/L), these xenobiotics can still pose a serious threat to the aquatic environments. Sub-surface flow constructed wetland systems (SSF-CWS) are biological systems used in wastewater treatment, and clay materials can be used as support matrices for these systems. Clay materials act not only as filters but they also can potentially remove organic pollutants due to its sorption properties. In this study a processed clay material, light expanded clay aggregates (LECA), was tested for their sorption capacity towards three widespread water polluting pharmaceuticals, namely clofibric acid (CA), ibuprofen (IB) and carbamazepine (CB). Sorption assays were done with aqueous solutions of the individual compounds and with their mixture at different concentrations from 1.0 to 50.0 mg L-1. The sorptive properties of LECA were also investigated using wastewater spiked with a mixture of the three compounds at the same concentrations tested for the aqueous solutions. Reversed phase HPLC with UV-Vis detection at 210, 222 and 227 nm for CB, IB and CA respectively was used to measure the compounds concentrations. For the single-compound solutions the HPLC analyses were performed in isocratic mode with a mobile phase composed by 75:25 acetonitrile:water with 0.1% (v/v) phosphoric acid. For the solutions containing the three compounds, the separation was performed using the same elution solvents and a gradient program. The total run time was 8 minutes, the flow rate was 1.0 mL min-1 and the injection volume was 20 µL. Calibration curves were constructed for standard solutions of CB, IB and CA individually, as well as solutions containing the three mixed compounds. The average areas of the compounds’ peaks were plotted against the standards concentrations resulting in linear correlations with R2 equal to or higher than 0.999 in every calibration curve. Whenever the measured concentrations were below the method’s LOQs of 0.27 mg L-1, 0.39 mg L-1 and 0.13 mg L-1 for CB, IB and CA respectively, the samples were pre-concentrated on LiChrolut® RP-18. All data were analyzed by the analysis of variance method (ANOVA, single factor) at different significance levels. Results for the individual compounds in aqueous solutions have shown that LECA presents higher removal rates for IB and CB (44 – 92% and 60 – 95% respectively) whereas for CA the removal rates are moderate but still significant (30– 58%). In any case, and for all the studied compounds, the % removal decreased with the increasing load, the lower % removal still correspond to increasing absolute amounts sorbed. When the three compounds are put simultaneously in contact with LECA there are evidences of competitive sorption among the studied compounds, with CB being the less affected compound of the three. When all the compounds were dissolved in wastewater, there was a slight loss of removal efficiency, probably due to an increased solubility in the aqueous media owing to the organic matter present in the wastewater or to competitive sorption effects. Considering the hydraulic and physico-chemical properties of LECA which make this material suitable for constructed wetlands applications, its sorption properties evidenced in this work make it especially interesting for applications aiming at the removal of this kind of pollutants from wastewaters

Sorption behavior of granular matrices for application in pharmaceutical removal by SSF constructed wetlands

In recent years, the occurrence and fate of pharmaceutically active compounds (PhACs) in the aquatic environment has been recognized as one of the emerging issues in environmental chemistry. Clofibric acid, ibuprofen and carbamazepine are some of the most frequently found PhACs in environmental monitoring studies. Some xenobiotics have already been successfully removed from contaminated waters using constructed wetlands (CW). Depuration of wastewaters in CWs is achieved by the concerted action between plant rhizomes, microorganisms and matrix component. CWs efficiency can be significantly improved by careful selection of the matrix, plants and microorganism used. Among several physico-chemical phenomena, sorption by the matrix plays an important role in the PhACs removal mechanism. It is important to select a matrix with a high sorption capacity, which depends on the physico-chemical properties of the material chosen. Previous studies carried out by the authors showed that expanded clay (LECA) presents a high sorptive affinity by clofibric acid [1]. The aim of the present work was to evaluate the capacity of LECA to remove other PhACs, namely ibuprofen and carbamazepine, and compare the results obtained with these pharmaceuticals with those obtained previously with clofibric acid. In addition, other materials were tested for the removal of clofibric acid and the results were compared with those obtained with LECA. The ultimate objective of this work will be to optimize the performance of this component in the overall performance of a constructed wetlands system designed for the removal of PhACs from wastewaters

Removal of pharmaceuticals in constructed wetlands using Typha and LECA. A pilot-scale study.

An ever-increasing number of xenobiotic compounds are getting detected in environmental samples worldwide. Serious concern about the contamination of water resources and drinking water supplies has aroused from the prevalence of pharmaceutical residues in the aquatic ecosystems. Some pharmaceuticals such as ibuprofen, carbamazepine and clofibric acid are frequently detected in waters [1]. These compounds are generally quantified at low concentrations (at the ng/L or mg/L range) but, due to their persistence in the environment and to potentially cumulative effects in the organisms, studies have shown that these compounds can have some damaging effects on the aquatic ecosystems [1]. Several xenobiotic organic compounds have already been removed from contaminated waters using constructed wetlands (CW) where the processes occurring in natural wetlands can be optimized in engineered man-made ecosystems, specifically designed for wastewater treatment. Among several physico-chemical phenomena, sorption by the support matrix plays an important role in the contaminant removal mechanisms. It is important to select a matrix with a high sorption capacity, which will depend on the physico-chemical properties of the material chosen. Previous studies have shown that expanded clay (LECA) is capable to remove, by sorption, this type of substances from water [2]. CWs also take advantage of the ability of plants to adsorb, uptake and concentrate pollutants, as well as to release root exudates that enhance compound biotransformation and degradation. Wetland species such as the cattail (Typha spp.) have already been tested and found suitable for the removal of several organic compounds from wastewaters, being commonly used in CWs [3]. The aim of the present work was to evaluate the efficiency of a subsurface flow constructed wetland assembled with the plants Typha spp. and LECA as support matrix, for the removal of three pharmaceuticals, namely ibuprofen, carbamazepine and clofibric acid, from contaminated waters

Academic success in schools in the Algarve: when leadership is part of the solution and not of the problem

This paper presents the results of a case study conducted among school principals in the southern region of Portugal, located in urban, suburban and rural settings. The five cases that comprise this study were subjected to a final rating of “Very Good” in the external evaluation process of schools, whose data were collected through semi-structured interviews and documentary analysis (regulations and educational project, reports of the external evaluation of responsibility of Inspeção Geral de Educação e Ciência de Portugal). The data collected in this exploratory study were systematized and analyzed according to the following indicators: the students’ academic success, the teachers’ professional development, the organizational development and the identifying features of schools principals. Overall, we cannot affirm the existence of differences according to geographical area, although some particularities which proved to be interesting and indicative of good leadership practices could be highlighted.info:eu-repo/semantics/publishedVersio

Para o estudo da evolução do ensino e da formação em administração educacional em Portugal

Estudos sobre a evolução do ensino de disciplinas, na formação de professores em Portugal, são recentes. O controle burocrático centralizado reteve as dimensões do controle político-administrativo. De certo modo, protegeu a esfera educativa das influências modernizantes, do capitalismo industrial e das lógicas mercantis e gerencialistas. Defendeu a educação do domínio político, da intervenção de movimentos sociais, das propagandas de ideais democráticos e da cidadania. A utilização da designação "Administração educacional" ilustra as dificuldades sentidas, ao longo dos últimos anos, em termos da construção acadêmica de uma área, seja pela falta de tradição, seja pelos antecedentes históricos.In Portugal, studies about the evolution of disciplines teaching in the teachers formation are recent. The centralized bureaucratic control has held back the dimensions of politic administrative control. In a certain way, it has protected the education against the new-fashioned influences, manufacturing capitalism, and mercantile and managerial logics. This centralized bureaucratic control has also profected the education against the politic dominion, the intervention of social movements, the advertising of democratic ideals, and against the citizenship. The use of the term "Educational administration" shows the difficulties met by the searchers along the latest years, since there is no tradiction nor historic antecedence

Íleo Meconial Complicado. Caso Clínico de Diagnóstico Antenatal

Descreve-se um caso clínico de íleo meconial com diagnóstico antenatal por ultrassonografia às 32 semanas de gestação. Após cesariana electiva às 37 semanas, o recém-nascido foi submetido a intervenção cirúrgica no primeiro dia de vida por quadro de oclusão intestinal secundário a íleo meconial complicado. Os testes laboratoriais confirmaram a presença de fibrose quística.Faz-se uma breve revisão da etiopatogenia do íleo meconial e realça-se a importância do diagnóstico antenatal no prognóstico desta afecção