Surface pressure-area isotherms for Langmuir monolayers and a docking molecular orientation of perylene tetracarboxylic derivatives on a water surface

The surface pressure-molecular area (pi-A) isotherms for Langmuir monolayers of four perylenetetracarboxylic (PTCD) derivatives, measured with varying subphase temperatures and compression speeds, are reported. The behavior of these PTCD derivatives at the water-air interface is modeled using the rigid docking method. This approach is the first attempt to model the molecular orientation of PTCD on the water surface to be compared with experimental Langmuir isotherms. Through this methodology, it would be possible to anticipate aggregation and determine if favorable spatial orientations of perylenes are generated on the water surface. The pi-A isotherm experiments show that these molecules can support high surface pressures, indicating strong packing on the water surface and that the isotherms are compression speed independent but temperature dependent. The molecular orientation and stacking was further examined in Langmuir-Blodgett (LB) monolayers deposited onto glass and glass coated with Ag island films using UV-visible absorption and surface-enhanced fluorescence (SEF) measurements.

Langmuir-Blodgett films incorporating an ionic europium complex

Langmuir-Blodgett (LB) technique is a powerful tool to fabricate ultrathin films with highly ordered structures and controllable molecular array for efficient energy and electron transfer, allowing the construction of devices at molecular level. One method to obtain LB films consists in the mixture of classical film-forming molecules, for example Stearic Acid (SA) and functional metal complex. In this work NH(4)[Eu(bmdm)(4)], where the organic ligand bmdm is (butyl methoxy-dibenzoyl-methane) or (1-(4-methoxyphenyl)-3-(4-tert-butylphenyl)propane-1,3-dione) was used to build up Langmuir and LB films. Langmuir isotherms were obtained from (i) NH(4)[Eu(bmdm)(4)] complex and (ii) NH(4)[Eu(bmdm)(4)]/SA (1:1). Results indicated that (i) form multilayer structure; however the surface pressure was insufficient to obtain LB films, and (ii) can easily reproduce and build LB films. The dependence of number of layers in the UV absorption spectra suggest that the complex did not hydrolyze or show decomposition, UV spectral differences observed between the solution and the LB film indicate that the complex has a highly ordered arrangement in the film and the complex has an interaction with SA. Excitation spectra confirm a ligand-europium energy transfer mechanism. The transition lines of Eu(3+) ion were observed in emission spectra of all films, the photoluminescence spectra indicate a fluorescence enhanced effect with the number of LB layers. (C) 2009 Elsevier B.V. All rights reserved.

Adsorção de íons Cu2+ em latossolo vermelho-amarelo húmico

In environmental studies it is necessary to know the adsorption behavior of metals by soils, since the unfavorable effects of heavy metals and even the micronutrients at high concentrations in the environment are related to these adsorbents' ability to immobilize them. A sample of a humic yellow red oxisol from Araponga region in the State of Minas Gerais, Brazil, was used to verify the adsorption behavior of Cu2+ ions in this substrate. The mathematical model described by Langmuir's adsorption equation in its linearized form was applied and the values of the maximum capacity b and those of the constant related to the bonding energy a were obtained. Aliquots of copper nitrate solutions containing several concentrations of this metal were added to soil samples, the pH being predetermined for developing the adsorption experiments. The chemical and physical characterization of soil sample were performed by determining the organic carbon, nitrogen and phosphorus concentrations, cation exchange capacity (CEC), pH, concentration of metals (Al, Fe, K, Mg, Ca, Zn, Cu, Ni, Cr, Co, Pb, and Cd), granulometric analysis and X-ray diffraction. Langmuir isotherms presented two distinct adsorption regions at both pH 4 and pH 5, showing that the adsorptive phenomenon occurs in two distinct stages. The adsorption sites for the lower part presented greater bonding energy and low adsorption capacity compared with the adsorption sites of the part of the curve corresponding to higher Cu concentrations in the equilibrating solution.

Phosphorus sorption and availability in soils amended with animal manures and sewage sludge

Soils that receive large applications of animal wastes and sewage sludge are vulnerable to releasing environmentally significant concentrations of dissolved P available to subsurface flow owing to the gradual saturation of the soil's P sorption capacity. This study evaluated P sorption (calculated from Langmuir isotherms) and availability of P (as CaCl2-P and resin P) in soils incubated for 20 d with poultry litter, poultry manure, cattle slurry, municipal sewage sludge, or KH2PO4, added on a P-equivalent basis (100 mg P kg(-1)). All the P sources had a marked negative effect on P sorption and a positive effect on P availability in all soils. In the cattle slurry- and KH2PO4- treated soils, the decreases in P sorption maximum (19-66%) and binding energy (25-89%) were consistently larger than the corresponding decreases (7-41% and 11-30%) in poultry litter-, poultry manure-, and sewage sludge-treated soils. The effects of cattle slurry and KH2PO4 on P availability were, in most cases, larger than those of the other P sources. In the poultry litter, poultry manure, and sewage sludge treatments, the increase in soil solution P was inversely related (R-2 = 0.75) to the input of Ca from these relatively high Ca (13.5-42 g kg(-1)) sources. Correlation analyses implied that the magnitude of the changes in P sorption and availability was not related to the water-extractable P content of the P sources. Future research on the sustainable application of organic wastes to agricultural soils needs to consider the non-P- as well as P-containing components of the waste.

Extração do corante reactive blue 19 utilizando tensoativo não iônico

The generation of effluent from the finishing process in textile industry is a serious environmental problem and turned into an object of study in several scientific papers. Contamination with dyes and the presences of substances that are toxic to the environment characterize this difficult treatment effluent. Several processes have already been evaluated to remove and even degrade such pollutants are examples: coagulation-flocculation, biological treatment and advanced oxidative processes, but not yet sufficient to enable the recovery of dye or at least of the recovery agent. An alternative to this problem is the cloud point extraction that involves the application of nonionic surfactants at temperatures above the cloud point, making the water a weak solvent to the surfactant, providing the agglomeration of those molecules around the dyes molecules by affinity with the organic phase. After that, the formation of two phases occurred: the diluted one, poor in dye and surfactant, and the other one, coacervate, with higher concentrations of dye and surfactants than the other one. The later use of the coacervate as a dye and surfactant recycle shows the technical and economic viability of this process. In this paper, the cloud point extraction is used to remove the dye Reactive Blue from the water, using nonionic surfactant nonyl phenol with 9,5 etoxilations. The aim is to solubilize the dye molecules in surfactant, varying the concentration and temperature to study its effects. Evaluating the dye concentration in dilute phase after extraction, it is possible to analyze thermodynamic variables, build Langmuir isotherms, determine the behavior of the coacervate volume for a surfactant concentration and temperature, the distribution coefficient and the dye removal efficiency. The concentration of surfactant proved itself to be crucial to the success of the treatment. The results of removal efficiency reached values of 91,38%, 90,69%, 89,58%, 87,22% and 84,18% to temperatures of 65,0, 67,5, 70,0, 72,5 and 75,0°C, respectively, showing that the cloud point extraction is an efficient alternative for the treatment of wastewater containing Reactive Blue

Hidrogeneoftalato de potássio como molécula modelo para estudos de adsorção sobre TiO2

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Analysis of Acid Alizarin Violet N Dye Removal Using Sugarcane Bagasse as Adsorbent

With the development of the textile industry, there has been a demand for dye removal from contaminated effluents. In recent years, attention has been directed toward various natural solid materials that are capable of removing pollutants from contaminated water at low cost. One such material is sugarcane bagasse. The aim of the present study was to evaluate adsorption of the dye Acid Violet Alizarin N with different concentrations of sugarcane bagasse and granulometry in agitated systems at different pH. The most promising data (achieved with pH 2.5) was analyzed with both Freundlich and Langmuir isotherms equations. The model that better fits dye adsorption interaction into sugarcane bagasse is Freundlich equation, and thus the multilayer model. Moreover, a smaller bagasse granulometry led to greater dye adsorption. The best treatment was achieved with a granulometry value lower than 0.21 mm at pH 2.50, in which the total removal was estimated at a concentration of 16.25 mg mL(-1). Hence, sugarcane bagasse proves to be very attractive for dye removal from textile effluents.

New phosphinate ligand synthesis and its effect on optical properties of the europium beta-diketonate complex

The synthesis and characterization of a new organic ligand monooctyldiphenylphosphinate (L) is described, as well as a new Eu(3+) diketonate complex [Eu(tta)(3)(L)(2)] (tta = thenoyltrifluoracetone). The ligand (L) was formed by substitution reaction (80% yield) and characterized by uni- and bidimensional (1)H, (13)C and (31)P NMR experiments, to confirm its molecular structure. The coordination of (L) to Eu(3+) in the complex [Eu(tta)(3)(L)(2)] was confirmed by FT-IR spectra. The emission spectra present the same profile when excited in Eu(3+) or in the ligands, suggesting an energy transfer from ligands to Eu(3+) ions. The emission spectra of the precursor [Eu(tta)(3)(H(2)O)(2)], and [Eu(tta)(3)(L(2))] present bands arising from f-f intra-configurational transitions. The only (5)D(0)-(7)F(0) transition shows the presence of at least one site without symmetry center. The FWHM of such transition is 7 cm(-1) and 57 cm(-1) for [Eu(tta)(3)(H(2)O)(2)] and [Eu(tta)(3)(L)(2)] complexes, respectively. This widening is provided by the presence of large groups around Eu(3+) ion. The calculated intensity parameters Omega(2) and Omega(4) show that the interaction features between center-ion and ligand are different; the small value of Omega(4) is related to long range effects of alkyl chain. The Langmuir isotherms of this ligand and complex have been investigated although their hydrolysis in water subphase does not allow stable monolayers. (C) 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

Preconcentration and determination of metal ions from fuel ethanol with a new 2,2'-dipyridylamine bonded silica

A silica surface chemically modified with [3-(2,2'-dipyridylamine) propyl] groups was prepared, characterized, and evaluated for its metal ion preconcentration in fuel ethanol. To our knowledge, we are the first authors who have reported the present modification on silica gel surface. The material was characterized using infrared spectra, scanning electronic microscopy, and 13C and 29Si solid-state NMR spectra. Batch and column experiments were conducted to investigate for metal ion removal from fuel ethanol. The results showed that the Langmuir model describes the sorption equilibrium data of the metal ions in a satisfactory way. From the Langmuir isotherms, the following maximum adsorption capacities (in mmolg -1) were determined: 1.81 for Fe(III), 1.75 for Cr(III), 1.30 for Cu(II), 1.25 for Co(II), 1.15 for Pb(II), 0.95 for Ni(II), and 0.87 for Zn(II). Thermodynamic functions, the change of free energy (ΔG), enthalpy (ΔH), and entropy (ΔS) showed that the adsorption of metal ions onto Si-Pr-DPA was feasible, spontaneous, and endothermic. The sorption-desorption of the metal ions made possible the development of a preconcentration and quantification method of metal ions in fuel ethanol. © 2012 Elsevier Inc.

Biosorption of cadmium (II) and lead (II) from aqueous solution using exopolysaccharide and biomass produced by Colletotrichum sp.

The biosorption of Cd(II) and Pb(II) ions on biomass and exopolysaccharide (EPS) produced by Colletotrichum sp. fungus has been investigated as a function of contact time, initial pH, initial metal ion concentration, and initial adsorbent concentration in a batch system. Adsorption equilibrium was described by Freundlich and Langmuir isotherms. Adsorption was characterized through granulometry, SEM and EDX analysis. Then, studies were performed to regenerate the adsorbent. Biosorption of metals by biomass and EPS were best described by the Langmuir and Freundlich isotherm, respectively. Results of thermodynamic investigations showed that adsorption reactions were spontaneous (ΔG° < 0), exothermal, and mainly physical. The EPS was able to remove 79 and 98% of cadmium and lead, respectively, and the biomass removed 85 and 84% of cadmium and lead, respectively, in a solution with initial concentration 100 mg L-1, and the four adsorption-desorption cycles of all adsorbents showed up with great regenerative capacity and relative stability after these four cycles, the high potential of these biological materials in sorption has been shown. © 2013 Copyright Balaban Desalination Publications.

Estudo da utilização de serragem de madeira como adsorvente para o tratamento de efluentes têxteis

The Brazilian textile industry has been a highlight in the global economy. Connected with this high economic performance there is the water consumption and the generation of great volumes of wastewater which present high concentrations of dyes and chemical substances. One of the main techniques used in the treatment of textile effluents is adsorption, which has the activated carbon as the main adsorbent. Recently, studies have been developed to find alternative materials to activated carbon and exhibiting good adsorption capacity of dyes. The aim of this work is to study the potential of sawdust as adsorbent of low cost to remove the dye Direct Green 26. The results of this type of dye removal were obtained through the study of adsorption isotherms obtained by spectrophotometry in the UV-visible region analyzed by the Langmuir model. Finally, a comparison was made of these results with those of other adsorbents. Results showed that the average removal of dye, using sawdust, was 78.8% for an initial concentration of 500mg / L and the maximum adsorption capacity of 119mg / g. These results demonstrate the great potential of sawdust as an adsorbent for the dye Direct Green 26.

Développement d’une lentille cornéenne médicamentée

L’utilisation de lentilles cornéennes peut servir à améliorer le profil d’administration d’un principe actif dans les yeux. Avec une efficacité d’administration de 5% par l’utilisation de gouttes, on comprend rapidement que l’administration oculaire doit être améliorée. Cette faible administration a donné naissance à plusieurs tentatives visant à fabriquer des lentilles cornéennes médicamentées. Cependant, à cause de multiples raisons, aucune de ces tentatives n’a actuellement été mise sur le marché. Nous proposons dans cette étude, une possible amélioration des systèmes établis par le développement d’une lentille cornéenne à base de 2-(hydroxyéthyle)méthacrylate (HEMA), dans laquelle des microgels, à base de poly N-isopropylacrylamide (pNIPAM) thermosensible encapsulant un principe actif, seront incorporé. Nous avons donc débuté par développer une méthode analytique sensible par HPCL-MS/MS capable de quantifier plusieurs molécules à la fois. La méthode résultante a été validée selon les différents critères de la FDA et l’ICH en démontrant des limites de quantifications et de détections suffisamment basses, autant dans des fluides simulés que dans les tissus d’yeux de lapins. La méthode a été validée pour sept médicaments ophtalmiques : Pilocarpine, lidocaïne, proparacaïne, atropine, acétonide de triamcinolone, timolol et prednisolone. Nous avons ensuite fait la synthèse des microgels chargés négativement à base de NIPAM et d’acide méthacrylique (MAA). Nous avons encapsulé une molécule modèle dans des particules ayant une taille entre 200 et 600 nm dépendant de la composition ainsi qu’un potentiel zêta variant en fonction de la température. L’encapsulation de la rhodamine 6G (R6G) dans les microgels a été possible jusqu’à un chargement (DL%) de 38%. L’utilisation des isothermes de Langmuir a permis de montrer que l’encapsulation était principalement le résultat d’interactions électrostatiques entre les MAA et la R6G. Des cinétiques de libérations ont été effectuées à partir d’hydrogels d’acrylamide chargés en microgels encapsulant la R6G. Il a été trouvé que la libération des hydrogels chargés en microgels s’effectuait majoritairement selon l’affinité au microgel et sur une période d’environ 4-24 heures. La libération à partir de ces systèmes a été comparée à des formules d’hydrogels contenant des liposomes ou des nanogels de chitosan. Ces trois derniers (liposomes, microgels et nanogels) ont présenté des résultats prometteurs pour différentes applications avec différents profils de libérations. Enfin, nous avons transposé le modèle développé avec les gels d’acrylamide pour fabriquer des lentilles de contact de 260 à 340 µm d’épaisseur à base de pHEMA contenant les microgels avec une molécule encapsulée devant être administrée dans les yeux. Nous avons modifié la composition de l’hydrogel en incorporant un polymère linéaire, la polyvinylpyrrolidone (PVP). L’obtention d’hydrogels partiellement interpénétrés améliore la rétention d’eau dans les lentilles cornéennes. L’encapsulation dans les microgels chargés négativement a donné de meilleurs rendements avec la lidocaïne et cette dernière a été libérée de la lentille de pHEMA en totalité en approximativement 2 heures qu’elle soit ou non encapsulée dans des microgels. Ainsi dans cette étude pilote, l’impact des microgels n’a pas pu être déterminé et, de ce fait, nécessitera des études approfondies sur la structure et les propriétés de la lentille qui a été développée. En utilisant des modèles de libération plus représentatifs de la physiologie de l’œil, nous pourrions conclure avec plus de certitude concernant l’efficacité d’un tel système d’administration et s’il est possible de l’optimiser.

Développement d’une lentille cornéenne médicamentée

L’utilisation de lentilles cornéennes peut servir à améliorer le profil d’administration d’un principe actif dans les yeux. Avec une efficacité d’administration de 5% par l’utilisation de gouttes, on comprend rapidement que l’administration oculaire doit être améliorée. Cette faible administration a donné naissance à plusieurs tentatives visant à fabriquer des lentilles cornéennes médicamentées. Cependant, à cause de multiples raisons, aucune de ces tentatives n’a actuellement été mise sur le marché. Nous proposons dans cette étude, une possible amélioration des systèmes établis par le développement d’une lentille cornéenne à base de 2-(hydroxyéthyle)méthacrylate (HEMA), dans laquelle des microgels, à base de poly N-isopropylacrylamide (pNIPAM) thermosensible encapsulant un principe actif, seront incorporé. Nous avons donc débuté par développer une méthode analytique sensible par HPCL-MS/MS capable de quantifier plusieurs molécules à la fois. La méthode résultante a été validée selon les différents critères de la FDA et l’ICH en démontrant des limites de quantifications et de détections suffisamment basses, autant dans des fluides simulés que dans les tissus d’yeux de lapins. La méthode a été validée pour sept médicaments ophtalmiques : Pilocarpine, lidocaïne, proparacaïne, atropine, acétonide de triamcinolone, timolol et prednisolone. Nous avons ensuite fait la synthèse des microgels chargés négativement à base de NIPAM et d’acide méthacrylique (MAA). Nous avons encapsulé une molécule modèle dans des particules ayant une taille entre 200 et 600 nm dépendant de la composition ainsi qu’un potentiel zêta variant en fonction de la température. L’encapsulation de la rhodamine 6G (R6G) dans les microgels a été possible jusqu’à un chargement (DL%) de 38%. L’utilisation des isothermes de Langmuir a permis de montrer que l’encapsulation était principalement le résultat d’interactions électrostatiques entre les MAA et la R6G. Des cinétiques de libérations ont été effectuées à partir d’hydrogels d’acrylamide chargés en microgels encapsulant la R6G. Il a été trouvé que la libération des hydrogels chargés en microgels s’effectuait majoritairement selon l’affinité au microgel et sur une période d’environ 4-24 heures. La libération à partir de ces systèmes a été comparée à des formules d’hydrogels contenant des liposomes ou des nanogels de chitosan. Ces trois derniers (liposomes, microgels et nanogels) ont présenté des résultats prometteurs pour différentes applications avec différents profils de libérations. Enfin, nous avons transposé le modèle développé avec les gels d’acrylamide pour fabriquer des lentilles de contact de 260 à 340 µm d’épaisseur à base de pHEMA contenant les microgels avec une molécule encapsulée devant être administrée dans les yeux. Nous avons modifié la composition de l’hydrogel en incorporant un polymère linéaire, la polyvinylpyrrolidone (PVP). L’obtention d’hydrogels partiellement interpénétrés améliore la rétention d’eau dans les lentilles cornéennes. L’encapsulation dans les microgels chargés négativement a donné de meilleurs rendements avec la lidocaïne et cette dernière a été libérée de la lentille de pHEMA en totalité en approximativement 2 heures qu’elle soit ou non encapsulée dans des microgels. Ainsi dans cette étude pilote, l’impact des microgels n’a pas pu être déterminé et, de ce fait, nécessitera des études approfondies sur la structure et les propriétés de la lentille qui a été développée. En utilisant des modèles de libération plus représentatifs de la physiologie de l’œil, nous pourrions conclure avec plus de certitude concernant l’efficacité d’un tel système d’administration et s’il est possible de l’optimiser.

Development of nanostructured hydrogel for spatial and temporal controlled release of active compounds

L’utilisation de nanovecteurs pour la livraison contrôlée de principes actifs est un concept commun de nous jours. Les systèmes de livraison actuels présentent encore cependant des limites au niveau du taux de relargage des principes actifs ainsi que de la stabilité des transporteurs. Les systèmes composés à la fois de nanovecteurs (liposomes, microgels et nanogels) et d’hydrogels peuvent cependant permettre de résoudre ces problèmes. Dans cette étude, nous avons développé un système de livraison contrôlé se basant sur l’incorporation d’un nanovecteur dans une matrice hydrogel dans le but de combler les lacunes des systèmes se basant sur un vecteur uniquement. Une telle combinaison pourrait permettre un contrôle accru du relargage par stabilisation réciproque. Plus spécifiquement, nous avons développé un hydrogel structuré intégrant des liposomes, microgels et nanogels séparément chargés en principes actifs modèles potentiellement relargués de manière contrôlé. Ce contrôle a été obtenu par la modification de différents paramètres tels que la température ainsi que la composition et la concentration en nanovecteurs. Nous avons comparé la capacité de chargement et la cinétique de relargage de la sulforhodamine B et de la rhodamine 6G en utilisant des liposomes de DOPC et DPPC à différents ratios, des nanogels de chitosan/acide hyaluronique et des microgels de N-isopropylacrylamide (NIPAM) à différents ratios d’acide méthacrylique, incorporés dans un hydrogel modèle d’acrylamide. Les liposomes présentaient des capacités de chargement modérés avec un relargage prolongé sur plus de dix jours alors que les nanogels présentaient des capacités de chargement plus élevées mais une cinétique de relargage plus rapide avec un épuisement de la cargaison en deux jours. Comparativement, les microgels relarguaient complétement leur contenu en un jour. Malgré une cinétique de relargage plus rapide, les microgels ont démontré la possibilité de contrôler finement le chargement en principe actif. Ce contrôle peut être atteint par la modification des propriétés structurelles ou en changeant le milieu d’incubation, comme l’a montré la corrélation avec les isothermes de Langmuir. Chaque système développé a démontré un potentiel contrôle du taux de relargage, ce qui en fait des candidats pour des investigations futures.

Avaliação de Impacto Ambiental, Valorização do Efluente e dos Resíduos Sólidos da Indústria Corticeira

A preocupação com o meio ambiente, nomeadamente na descarga de águas residuais, consumo de água excessivo e produção de resíduos industriais, está cada vez mais presente no quotidiano. Devido a estas problemáticas, efetuou-se a avaliação de impacte ambiental (AIA) do processo produtivo das rolhas de cortiça naturais, tratamento das águas de cozedura da cortiça (estudo da possível reutilização do efluente tratado) e valorização de subprodutos – resíduo sólido (raspa de cortiça), sendo estes os objetivos propostos para a realização da presente dissertação. Na AIA, efetuada no decorrer das fases da Análise do Ciclo de Vida (ACV), foram selecionadas 8 categorias de impacte – aquecimento global, acidificação, dessecação, toxicidade e ecotoxicidade, eutrofização, consumo de recursos não renováveis e oxidação foto-química. A água de cozedura caracterizou-se por uma elevada carga poluente, apresentando elevada concentração de cor, Carência Química de Oxigénio (CQO), taninos e lenhina e Sólidos Suspensos Totais (SST). O processo de tratamento proposto consistiu num pré-tratamento por ultrafiltração (UF), com membranas de 30.000 e 20.000 MWCO, seguido de adsorção por carvão ativado (comercial e produzido a partir de raspa de cortiça). No tratamento por UF, utilizando uma membrana de 30.000 MWCO, foram obtidas percentagens de remoção para a primeira amostra de água de cozedura de 74,8 % para a cor, 33,1 % para a CQO e para a segunda amostra de 85,2 % para a cor e 41,8 % para a CQO. Posteriormente, apenas para a segunda amostra de água de cozedura e com uma membrana de 20.000 MWCO, as percentagens de remoção obtidas foram superiores, de 93% para a cor, 68,9 % para a CQO, 88,4 % para taninos e lenhina e 43,0 % para azoto total. No tratamento por adsorção com carvão ativado estudou-se o tempo de equilíbrio do carvão ativado comercial e do carvão ativado produzido a partir de aparas de cortiça, seguindo-se o estudo das isotérmicas de adsorção, no qual foram analisados os parâmetros da cor e CQO para cada solução. Os ajustes dos modelos teóricos aos pontos experimentais demonstraram que ambos os modelos (Langmuir e Freundlich) poderiam ser considerados, uma vez que apresentaram ajustes idênticos. Relativamente ao tratamento de adsorção em contínuo do permeado, obtido por UF com membrana de 20.000 MWCO, constatou-se que ambos os carvões ativados (comercial e produzido) não ficaram saturados, tendo em consideração os tempos de saturação estimados pela capacidade máxima de adsorção (determinada para a isotérmica de Langmuir) e as representações gráficas dos valores experimentais obtidos para cada ensaio. No ensaio de adsorção com carvão ativado comercial verificou-se que o efluente tratado poderia ser descarregado no meio hídrico ou reutilizado no processo industrial (considerando os parâmetros analisados), uma vez que até aos 11 minutos de ensaio a concentração da solução à saída foi de 111,50 mg/L O2, para a CQO, e incolor, numa diluição de 1:20. Em relação à adsorção em contínuo com carvão ativado produzido verificou-se no ensaio 4 que o efluente resultante apresentou uma concentração de CQO de 134,5 mg/L O2 e cor não visível, numa diluição de 1:20, ao fim de 1h22 min de ensaio. Assim, concluiu-se que os valores obtidos são inferiores aos valores limite de emissão (VLE) presentes no Decreto-Lei n.º 236/98 de 1 de Agosto. O carvão ativado produzido apresentou elevada área superficial específica, com 870 m2/g, comparativamente ao carvão comercial que foi de 661 m2/g. O processo de extração da suberina a partir de raspa de cortiça isenta de extraíveis, efetuado através da metanólise alcalina, apresentou percentagens de extração superiores aos restantes métodos. No processo efetuado em scale-up, por hidrólise alcalina, obteve-se uma extração de 3,76 % de suberina. A aplicação da suberina no couro demonstrou que esta cera apresenta enormes potencialidades, uma vez que a sua aplicação confere ao couro um aspeto sedoso, com mais brilho e um efeito de “pull-up”.