Recovery of metals with high commercial value through adsorption by chars from rice wastes (Rice2Metal)

Rice is the second most produced cereal in the world and Portugal is the major consumer and fifth larger producer in Europe. Its production generates significant amounts of wastes, namely rice husk (RH), rice straw (RS) and polyethylene (PE) from agricultural plastics. Currently, the destinations of these wastes are not the most environmental adequate, so different routes of valorisation are required. Having these materials interesting lower heating values (LHV), their valorisation in thermochemical processes, such as pyrolysis and gasification, became a possibility. These processes generate different products with energetic value (gasification generates mainly synthesis gas and pyrolysis mainly products are liquids, though some gases are also obtained). However, a solid fraction (char) is also produced in both thermochemical processes, which can be valorised as adsorbent materials. Several industries have led to an increase in metal-contaminated wastewaters, which are directly or indirectly discharged into the environment, especially in underdevelopment and developing countries. Therefore, it is necessary to treat metal-contaminated wastewaters prior to their discharge into the environment. Chromium (Cr) and Tungsten (W) are two metallic elements that can be found in several industrial wastewaters. Additionally, the European Union (EU) published, in 2014, a list of 20 substances whose recovery is a priority for Europe. Chromium (Cr) and tungsten (W) were in this list due to their economic importance to the industry sector. In this context, the main objective of this work was to evaluate the feasibility of using chars from the pyrolysis and gasification of RH, RS and PE, in the removal of Cr (as Cr(III)) and W (as WO42-) from aqueous solutions. In some situations, optimisation processes were necessary in order to improve the chars’ properties and efficiency in the adsorption/removal processes. For comparison purposes, a commercial activated carbon (CAC) was also used. Regarding the several chars used on Cr(III) removal only two gasification chars (G4C and G5C) and one pyrolysis char (P1C) were selected to be used in the removal assays under batch conditions. Despite of the very low surface area of the chars, the gasification chars were used without any activation, due to their high mineral content, allowing removal by ion exchange. However, the pyrolysis char required further optimization to improve its adsorptive capacity. Different activations (physical and chemical) were applied to P1C char. G4C char presented the best result among the gasification chars, achieving uptake capacities of 8.19 mg g-1 in the synthetic solution (3.93 mg g-1 for CAC) and 14.9 mg g-1 in the tannery industry wastewater (16.1 mg g-1 for CAC). P1C physically activated (P1C+PA) presented the highest uptake capacities of all pyrolysis-derived activated carbons obtaining values of 9.23 mg g-1 in the synthetic solution (9.80 mg g-1 for CAC) and 12.4 mg g-1 in the industrial wastewater (16.1 mg g-1 for CAC). G4C char was selected to be used in the column assays under dynamic conditions, but the performance of both G4C and CAC was lower than in the batch assays, obtaining uptake capacities of 1.60 and 2.14 mg g-1 in the synthetic solution and 3.25 and 7.83 mg g-1 in the industrial wastewater, respectively. These results suggest that under batch conditions G4C and P1C+PA showed good properties to be alternative adsorbents in the removal of Cr(III) from liquid effluents, since their performance can be considered comparable to the commercial sample. For the WO42 adsorption assays, six pyrolysis-derived activated carbons were produced. The chemical activation with KOH originated the pyrolysis-derived activated carbon (P4C+KOH) with the best results on WO42 adsorption. The highest uptake capacities found for P4C+KOH were 854 mg g-1 in the synthetic solution, and 1561 mg g-1 in the industrial wastewater from a mining industry, while CAC’s values were significantly lower (113 and 572 mg g-1, respectively). P4C+KOH activated carbon clearly showed better properties than CAC on WO42- adsorption, obtaining uptake capacities almost 8 times higher in the synthetic solution and almost 3 times higher in the mining wastewater. These results suggest that P4C+KOH seems to be a much more efficient alternative to CAC in the adsorption of WO42- from liquid effluents. The main objective of the work was achieved as for both Cr and W removal it was possible to produce alternative adsorbents to the typical commercial activated carbon. Concerning Cr, the adsorbents produced obtained similar results to CAC, while for W the expectations were widely exceeded, as the produced adsorbents largely overcame CAC’s results

Sustainable Economic Development: The Necessary Dialogue between Environmental Law and Economics

This article aims to analyze the distinction between the concepts of economic growth, economic development, sustainable development and environmental justice; the inter-action between Environmental Law and Economics in the paradigm of environmental justice, and what is the purpose of such interaction; and environmental justice as a possible solution to the installed state of environmental imbalance. To this end, the concepts of economic growth, economic development, sustainable development and environmental justice are investigated; Complexity Theory and its transdisciplinary approach; and environmental justice as a new order capable of reversing a state of installed environmental imbalance. To obtain the results desired by the research, the method of approach to be followed will be the empirical-dialectical, using bibliographic research, having as a reference system of the Law and Economics of Richard A. Posner. In conclusion, it is pointed out that there is a need for a new development model, which, based on transdisciplinarity, should seek solutions in favor of socioeconomic-environmental balance for present and future generations, as a way of overcoming the state of environmental imbalance installed, as well as all the economic, political, cultural, social and environmental impacts caused by it

Estudo da produção em escala aumentada de nanopartículas de dissulfeto de molibdênio (2H-MoS2) pelo método hidrotérmico

Dissertação (Mestrado) - Universidade Federal de Santa Catarina, Centro Tecnológico. Programa de Pós-Graduação em Ciência e Engenharia de Materiais, Florianópolis, 2012No presente trabalho foi desenvolvido um método de produção em escala aumentada de nanopartículas de dissulfeto de molibdênio (MoS2). Foi utilizada a rota hidrotérmica para sua produção, sendo projetado um forno de aquecimento resistivo com capacidade para 9 autoclaves. Estas foram confeccionadas em aço SAE 310, revestidas internamente com politetrafluoretileno (PTFE), tendo 120 ml de volume interno cada. Este forno conta com um assoalho vibratório capaz de manter as autoclaves sob agitação constante, alcançando até dois modos vibracionais fundamentais do conteúdo líquido no interior delas. As sínteses foram desenvolvidas na temperatura de 220°C em períodos de 6, 12 e 24 horas, tendo como reagentes o molibdato de amônio tetrahidratado, hidroxilamina cloridrato e tioureia, sendo a reação dada em água bidestilada. As amostras foram caracterizadas quanto ao seu rendimento químico, estrutura cristalina por Difração de Raios X (DRX), morfologia por Microscopia Eletrônica de Varredura por Emissão de Campo (FEG), Termogravimetria e Infravermelho por Transformada de Fourier (TG-IR) simultaneamente, Espectroscopia Raman, Interferometria Óptica e, com enfoque maior, Tribologia. Foram obtidas nanopartículas na morfologia de nanoflores com cerca de 200 nm de diâmetro com estrutura cristalina hexagonal lamelar (2H-MoS2) parcialmente amorfizadas. Estas formam dispersões relativamente estáveis com os três óleos sintéticos testados (fortemente polar, de média polaridade e apolar) e com água bidestilada. Obteve-se um rendimento médio de reação de 71,3% em relação ao Mo e foi verificado um aumento de 10% neste quando comparado com amostras estáticas, sem a aplicação da agitação por vibração. Desta forma, valores para uma produção industrial utilizando o sistema desenvolvido ficam em torno de 300 g/mês.Abstract : In the present work was developed a method for scaling up the production of molybdenum disulfide (MoS2) nanoparticles. It was used a hydrothermal route to its production, being designed a resistive heating furnace with capacity for 9 autoclaves. They were designed in SAE 310 stainless steel, internally coated with polytetrafluoroethylene (PTFE), having 120 ml internal volume each. This furnace has a vibratory floor capable of maintaining the autoclaves under stirring, reaching until two fundamental vibrational modes of the liquid contents inside them. The syntheses were developed at temperature of 220 °C in periods of 6, 12 and 24 hours, with the reagents of ammonium molybdate tetrahydrate, hydroxylamine hydrochloride and thiourea, the reaction is given in bidistilled water. The samples were characterized according to their chemical yield, crystalline structure by X-ray Diffraction (XRD), morphology by Field Emission Scanning Electron Microscopy (FEG), Thermogravimetry and Fourier Transform Infrared (TG-IR) simultaneously, Raman Spectroscopy, Optical Interferometry and, with increased focus, Tribology. Nanoparticles were obtained on the morphology of nanoflowers about 200 nm diameter with lamellar hexagonal crystalline structure (2H-MoS2) partially amorphous. These form relatively stable dispersions with the three synthetic oils tested (strongly polar, medium polarity and nonpolar) and with bidistilled water. It was obtained an average reaction yield of 71.3% in relation to Mo and there was verified an increment of 10% in it in comparison with static samples, without the application of stirring by vibration. Thus, values for an industrial production using the developed system are around 300 g / month

Fast and Mobile Cataract Detection by Applying Line Laser Eye Illumination

Cataract is observed when the eye lens becomes opaque. This condition causes blurred vision and is the main cause of blindness worldwide. Cataract diagnosis is usually performed during ophthalmologist examination using a slit lamp, which requires expertise, is expensive and bulky. In this study, we present a small handheld illumination setup for cataract detection. Ex-vivo porcine eyes are investigated to determine whether colored line lasers, 450 nm (blue), 520 nm (green) and 650 nm (red), which shine obliquely into the eye, are principally suited for detection of the Y shaped suture cataract and of cold cataract, respecting exposure limits of EU guideline 2006/25/EC. Camera images of the cataract exhibited good results under illumination with all line lasers. Observations with the physician’s eye led to an even better diagnosis of cataract. Generally, green laser light illumination was the best choice for cataract detection. With red laser light illumination it was also possible, but least suitable for this purpose. With this method, line lasers are a good choice for cataract identification, as cataract can be detected quickly and without much effort. This type of line laser illumination of the eye is safe and both types of cataract are detectable with all wavelengths. For the human eye, a further development of this system is conceivable

Logarithmic visual acuity charts: reasons to use and how to design it

A acuidade visual representa o inverso do ângulo visual, ou seja, da menor distância angular entre dois pontos que podem ser vistos como separados. Apesar de ser a medida da função visual mais comum na prática oftalmológica, é muitas vezes interpretada erroneamente, principalmente devido às inúmeras tabelas e diferentes sistemas de notações empregados na clínica. Este artigo revisa alguns conceitos sobre a quantificação da acuidade visual, suas principais notações e tabelas de medida, discutindo as vantagens do uso da escala logarítmica.Visual acuity represents the visual angle or the smallest distance between two points that allows their discrimination as separated points. Although it is the most common clinical measurement of visual function, it is often misunderstood, especially due to the variety of charts and different notation systems employed for its quantification. This article reviews some concepts about visual acuity measurement, the main notation systems, type of charts and discuss the advantages of using logarithmic scales

Companies and Sustainable Development: The Adequacy of Environmental Impact Assessment for the Management of Environmental Risks

The choice of the environmental risk management instrument to be used within the scope of corporate governance in companies is of paramount importance to avoid or mitigate the triple environmental responsibility to which they are exposed. In this sense, the following research problem arises: The Environmental Impact Assessment (EIA), an instrument of the National Environment Policy and a model of environmental risk management adopted by some companies, proves to be efficient, effective and effective for the fulfillment of the duty to protect the environmental balance and, therefore, for sustainable development? The present study aims to elucidate this research problem. To this end, analyzes were carried out on risk and environmental damage, from a perspective of the socioenvironmental function of companies today; the need for a new posture by companies in view of the reflexes of environmental risks in business activity; and the question of the adequacy or inadequacy of the EIA as an instrument of the National Environment Policy and as a model for managing environmental risks and damages, in the pursuit of sustainable development. The method of approach used was the deductive one, and the research was carried out using the method of bibliographic procedure, through which research was carried out on books, scientific articles and legislation. The result points out the inefficiency and ineffectiveness of the EIA for the management of environmental risks and, thus, for the fulfillment of the duty to protect the environmental balance by companies

Técnica alternativa para reduzir a perda de medicação durante injeção intravítrea

PURPOSE: To describe an intravitreal injection technique using a commercially available 29-gauge insulin needle syringe (29GN syringe) and a 21-gauge (G) needle, comparing compound waste associated with this technique application and the one described in ranibizumab (Lucentis®) kit instructions. METHODS: Ten 0.3 ml doses of distilled water were aspirated using the 29GN syringe and 21G needle (PT technique), and another ten equal doses were aspirated employing the sterilized Lucentis® kit (LK technique), which contains a 1ml tuberculin syringe, a 18G needle for compound aspiration and a 30G needle for intravitreal injection. For aspiration using the PT technique, a 21G needle is attached over a 29GN syringe. After compound aspiration, the 21G needle is removed and intravitreal injection is performed using the 29G needle. Using a precision balance, the aspiration needles (21G for PT; 18G for LK) were weighed before and after water aspiration and the syringe-needle complexes for injection (29GN for PT; 30G for LK) were weighed before aspiration and after emptying them. The volumes left in the aspiration needles and needle-syringe complexes were estimated by the difference in weight in grams, which were converted to millilitres. RESULTS: The mean (±SD) residual volume (ml) of aspiration needles (21G for PT; 18G for LK) was significantly lower with PT technique (0.0034 ± 0.0016) when compared to LK tech nique (0.0579 ± 0.0011) (p<0.01). The mean (±SD) residual volume (ml) of syringe-needle complexes was significantly lower with PT technique (0.0056 ± 0.0011) than with LK (0.0906 ± 0.003 ml) (p<0.01). CONCLUSION: The proposed technique is a reasonable alternative for minimizing medication loss during intravitreal injection procedures.OBJETIVO: Descrever técnica de injeção intravítrea utilizando agulha-seringa de 29 gauge (seringa 29GN) e agulha 21 gauge (G) comercialmente disponíveis, comparando perda de composto associada à aplicação desta técnica com a descrita nas instruções do kit do ranibizumabe (Lucentis®). MÉTODOS: Dez doses de 0,3 ml de água destilada foram aspiradas com a seringa 29GN e a agulha 21G (técnica PT) e outras dez doses iguais foram aspiradas utilizando-se o kit do Lucentis® (técnica LK). Para aspiração com a técnica PT, a agulha 21G é colocada sobre a seringa 29GN. Depois da aspiração, a agulha 21G é removida e a injeção intravítrea é realizada com a agulha 29G. A técnica LK utiliza seringa de tuberculina de 1 ml acoplada a agulha 18G para aspiração e agulha 30G para injeção intravítrea. Usando balança de precisão, as agulhas de aspiração (21G para PT; 18G para LK) foram pesadas antes e depois da aspiração da água e os complexos agulha-seringa para injeção (29GN para PT; 30G para LK) foram pesados antes da aspiração e após serem esvaziados. Os volumes restantes nas agulhas de aspiração e complexos agulha-seringa foram estimados pela diferença dos pesos em gramas com conversão para mililitros. RESULTADOS: O volume (ml) residual médio (±DP) das agulhas de aspiração (21G para PT; 18G para LK) foi significativamente menor com a técnica PT (0,0034 ± 0,0016) quando comparado à técnica LK (0,0579 ± 0,0011) (p<0,01). O volume (ml) residual médio (±DP) dos complexos agulha-seringa foi significativamente menor com a técnica PT (0,0056 ± 0,0011) do que LK (0,0906 ± 0,003 ml) (p<0,01). CONCLUSÃO: A técnica de injeção proposta é uma alternativa razoável para minimizar perda de medicação durante aplicação de injeções intravítreas

Estudo da valorização de cinzas de biomassa na produção de materiais para a construção de recifes artificiais

Dissertação para obtenção do Grau de Mestre em Energia e BioenergiaA utilização de betão, com cinzas de biomassa incorporadas, em estruturas de protecção costeira, é algo que tem vindo a ser estudado (Lukens e Selberg, 2004). Os recifes artificiais multifuncionais são uma solução recente de protecção costeira que também promove a biodiversidade de espécies e cria condições favoráveis à prática de desportos de ondas (Ranasingue, 2006; Almeida, 2007; Voorde et al., 2008; Mendonça et al., 2010; ASR Limited, 2011). O objectivo deste trabalho centrou-se em desenvolver diversas formulações de betão, com cinzas de biomassa incorporadas, cuja finalidade é ser utilizado em recifes artificiais. Foram recolhidas cinzas de fundo e cinzas volantes de uma central de valorização térmica de resíduos de biomassa florestal, com combustão em LFB. As cinzas foram fraccionadas granulometricamente e as suas fracções granulométricas foram submetidas a uma lixiviação com razão L/S = 10 L/kg (EN 12457-2) e a uma digestão ácida (USEPA 3051A) e alcalina (USEPA 3060A). Os lixiviados e os digeridos de cada fracção foram caracterizados do ponto de vista químico. Os lixiviados foram ainda caracterizados do ponto de vista ecotoxicológico. O teor de metais foi mais elevado nas fracções de menor dimensão granulométrica das cinzas de fundo e volantes, sendo, maioritariamente, compostos por metais alcalinos ou alcalino-terrosos. De um modo geral, os metais apresentaram maior solubilidade nas fracções de maior dimensão granulométrica. Segundo o CEMWE (ADEME, 1998), todas as fracções foram classificadas como ecotóxicas, à excepção da fracção >10000 μm das cinzas de fundo. Verificou-se uma tendência para a ecotoxicidade diminuir com o aumento da dimensão da granulometria das fracções. Foram também preparadas treze formulações de betão, uma de referência e doze com diferentes percentagens de cinzas volantes e cinzas de fundo, que substituíram o cimento e os agregados, respectivamente. As formulações foram submetidas a ensaios de compressão mecânica após 28, 60 e 90 dias de maturação. Verificou-se um aumento da resistência mecânica dos betões ao longo do tempo. Para além da formulação de referência (F1), foram seleccionadas duas formulações para serem analisadas posteriormente, segundo o seguinte critério de selecção: i) a formulação de betão que apresentasse a maior resistência mecânica e ii) a formulação de betão que permitisse maximizar a relação percentagens de substituição/resistência mecânica. A primeira formulação seleccionada tinha 10% de substituição de cimento por cinzas volantes e 40% de substituição de agregados por cinzas de fundo (F4). A segunda formulação seleccionada tinha 30% de substituição de cimento por cinzas volantes e 40% de substituição de agregados por cinzas de fundo (F12). As formulações seleccionadas foram submetidas a dois ensaios de lixiviação L/S = 10 L/kg (EN 12457-2). Num dos ensaios utilizou-se uma água marinha sintética (meio ASPM) como agente lixiviante e no outro utilizou-se, como agente lixiviante, uma água dulciaquícola sintética (ISO 6341). Os lixiviados produzidos foram submetidos a uma caracterização química e ecotoxicológica. Em ambos os lixiviados, e para todas as formulações caracterizadas, não foi evidenciada qualquer ecotoxicidade, segundo o CEMWE (ADEME, 1998). O objectivo proposto inicialmente foi atingido, pois obtiveram-se betões com resistências mecânicas adequadas à aplicação a que se destinam, reduzidas emissões químicas e níveis de ecotoxicidade inexistentes ou muito reduzidos

Possíveis mecanismos de recuperação da função da retina com uso de terapia celular com células tronco derivadas da medula óssea

Bone marrow has been proposed as a potential source of stem cells for regenerative medicine. In the eye, degeneration of neural cells in the retina is a hallmark of such widespread ocular diseases as age-related macular degeneration (AMD) and retinitis pigmentosa. Bone marrow is an ideal tissue for studying stem cells mainly because of its accessibility. Furthermore, there are a number of well-defined mouse models and cell surface markers that allow effective study of hematopoiesis in healthy and injured mice. Because of these characteristics and the experience of bone marrow transplantation in the treatment of hematological disease such as leukemia, bone marrow-derived stem cells have also become a major tool in regenerative medicine. Those cells may be able to restore the retina function through different mechanisms: A) cellular differentiation, B) paracrine effect, and C) retinal pigment epithelium repair. In this review, we described these possible mechanisms of recovery of retinal function with the use of cell therapy with bone marrow-derived stem cells.As células tronco derivadas da medula óssea têm sido propostas como uma fonte em potencial de células para medicina regenerativa. No olho, a degeneração de células neurais da retina são a marca de doenças difusas, como a degeneração macular relacionada com a idade (DMRI) e a retinose pigmentar. A medula óssea é um tecido ideal para estudar as células tronco por causa da sua acessibilidade. Devido a estas características e a experiência do transplante de medula óssea no tratamento de doenças hematológicas, como as leucemias, as célulastronco derivadas da medula óssea têm se tornado a maior ferramenta na medicina regenerativa. Essas células podem ser capazes de restaurar a função da retina através dos seguintes mecanismos: A) diferenciação celular; B) efeito parácrino; C) reparo do epitélio pigmentado da retina. Nesta revisão nós descrevemos os possíveis mecanismos de recuperação da função da retina com uso de terapia celular com células tronco derivadas da medula óssea