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Recuperação de óxido de escândio de alta pureza de resíduos industriais da cadeia de produção do níquel. / Recovery of high purity scandium oxide from industrial wastes of nickel production.Ariane Gaspari Oliveira Souza 29 April 2016 (has links)
O Escândio é um elemento terra rara, utilizado principalmente em ligas de alumínio, células combustíveis de óxido sólido e na produção de lâmpadas de haletos metálicos. Apesar de ser o 31° elemento mais abundante na crosta terrestre, raramente é encontrado concentrado na crosta terrestre, e sua produção é sempre associada ao processamento de outros minerais na forma de um subproduto, ou a recuperação de sucata. Minérios de Níquel podem conter teores de Sc variando de 50 a 350ppm e resíduos gerados durante seu processamento pode concentrar o Sc acima de 1000ppm. A recuperação do Escândio de um resíduo da cadeia de produção do Níquel foi estudada, de modo a obter um óxido com pureza acima de 99,0% para aplicações industriais. O resíduo utilizado é um precipitado, na forma de hidróxido, e contém principalmente Fe, Cu, Ni e Co, sendo o teor de Escândio em base seca aproximadamente 1000ppm. O processo de recuperação proposto consiste na lixiviação atmosférica do resíduo, precipitação seletiva para concentração do escândio e extração por solventes. A lixiviação atmosférica em meio sulfúrico 2,0mol.L-1 a 70°C permitiu a recuperação de 92,5% do Escândio contido no resíduo. Entretanto, não foi seletiva, lixiviando também parte dos demais metais presentes. Após a lixiviação para concentrar o Escândio, antes da extração por solventes, foi realizada uma precipitação com NaOH. O intuito foi precipitar o Fe, principal contaminante presente no lixiviado, entretanto ocorreu a co-precipitação de 95,5% do Sc junto a 65,6% Fe em pH 2,0. O precipitado representou uma concentração do Escândio do resíduo em 5,6 vezes. Esse concentrado de Escândio obtido foi dissolvido em solução de H2SO4 para recuperação do Escândio por extração por solventes. O extrante escolhido foi o Cyanex 923, uma mistura de óxidos alquil-fósfinicos. O mecanismo de extração do Sc pelo Cyanex 923 observado foi a solvatação e a estequiometria da reação 1:2. Foi observado um aumento na extração do Sc com o aumento da concentração de H+. O processo de extração do Sc com o Cyanex 923 é exotérmico, sendo favorecido a temperatura ambiente. O teor de Fe na solução aquosa antes da extração é 35 vezes maior que o Escândio, e apesar do Cyanex 923 ser mais seletivo para o Sc do que para o Fe, parte do Fe é co-extraído. O Fe co-extraído foi removido da fase orgânica por meio de uma lavagem com H2SO4 3mol.L-1 com uma perda de Sc de 1,3%. A reextração do Sc na fase orgânica não foi efetiva utilizando ácidos fortes devido a formação de um complexo estável. Foi utilizado ácido oxálico, técnica consolidada para reextração de terras raras, para recuperação do Sc da solução orgânica e a recuperação do Sc foi de 84,3% para uma solução com 4,0% de ácido oxálico. O oxalato de Sc precipitado foi recuperado por filtração e calcinado a 600°C. O óxido obtido apresentou pureza mínima de 99,0%. / Scandium is a rare earth element, used mainly in special aluminum alloys, SOFC\'s and metal halide lamps production. Despite of being the 31st element more abundant in Earth\'s Crust, it is rarely found concentrated in ores, and its production is always related to other minerals processing as a by-product or scrap recovering. Scandium content in Nickel ore may vary between 50 and 350ppm and residues produced during its processing can concentrate Sc above 1000ppm. Scandium recovery from a residue of Nickel processing was studied in order to obtain an oxide with purity higher than 99,0% for industrial applications. The residue used is a hydroxide precipitate, which contains mainly Fe, Cu, Ni and Co, Sc content is around 1000ppm (dry basis). The recovery process proposed consists in atmospheric leaching of the residue, selective precipitation to concentrate the Scandium and solvent extraction. The atmospheric leaching in sulfuric acid 2,0mol.L-1 at 70°C allowed the recovery of 92,5% of the Scandium present in the residue. However it was not selective and part of the other metals present in the residue were also leached. After leaching, in order to concentrate the Sc before solvent extraction, a precipitation with NaOH was performed. The initial aim was to precipitate the Iron - main contaminant present in the leach liquor - nevertheless it occurred the co-precipitation of 95,5% of the Sc besides 65,6% of Fe in pH 2,0. The precipitantion represented a concentration of the Sc in the residue of 5,6 times. The Scandium concentrate obtained was dissolved in a sulfuric acid solution to Sc recovery by solvent extraction. The extractant selected was Cyanex 923, a mixture of alkyl-phosphinic oxides. The mechanism of extraction of Scandium observed was solvation and reaction stechiometry was 1:2. It was observed an increase in Sc extraction rates by increasing the concentration of H+. The extraction of Scandium with Cyanex 923 is exothermic, and favorable at room temperature. The Iron content in aqueous solution before extraction is 35 times higher than that of Scandium, and even though Cyanex 923 being more selective for Sc than Fe, part of the Fe is co-extracted. The Fe co-extracted was removed of the organic phase by H2SO4 3mol.L-1 scrubbing with a Sc loss of 1,3%. The stripping of Scandium from organic phase was not accomplished by using strong acids due to formation of a stable complex. Afterwards, it was used oxalic acid - a technique consolidated for rare earths stripping - and the Sc recovery of organic phase was 84,3% with a solution of 4,0% oxalic acid. The Scandium oxalate precipitated was recovered by filtration and calcinated at 600°C. The Scandium oxide obtained presented 99,0% minimum purity.
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Aplicação de um quaternário amoniacal visando melhorar o desempenho da madeira tratada com octaborato de sódio / Application of an ammonium quaternary in order to improve the performance of treated wood with sodium octaborateJackson Marcelo Vidal 07 February 2012 (has links)
Com a evolução da civilização, a busca pela praticidade e durabilidade dos materiais desafia a pesquisa e o desenvolvimento de novos materiais e produtos. A preservação de madeiras tal como hoje a conhecemos, iniciou-se a partir da segunda metade do século XIX e, também vem se expandindo e impulsionando a busca por novos desenvolvimentos. Neste contexto, os boratos são preservativos amplamente reconhecidos e eficazes devido às suas características apreciáveis. Custo vantajoso, reduzido impacto ambiental, largo espectro de ação, o credenciam como um preservativo potencial para o desenvolvimento de estudos no sentido de redução de sua taxa de lixiviação. O objetivo deste trabalho foi avaliar a possiblidade de redução da lixiviação de uma composição contendo octaborato dissódico tetrahidratado e um quaternário graxo amoniacal, em madeira de Pinus elliotii, tratada sob pressão. Avaliouse também a interferência da adição do quaternário graxo amoniacal, frente ao ataque de cupins de madeira seca. Amostras de madeira foram tratadas para as retenções de 2,8 kg/m3 e 4,5 kg/m3 em B2O3, variando-se a proporção do quaternário amoniacal de 0,0%, 1,0%, 1,5% e 2,0%. Um conjunto de amostras foi submetido ao ensaio de lixiviação, com coletas de água nos períodos de 1, 2 e 4 horas. Após estas coletas, os corpos de prova foram retirados do sistema de lixiviação e, secos à temperatura ambiente por 16 horas. Passado este período, os corpos de prova retornaram à lixiviação, e coletas foram reiniciadas após 8, 16 e 48 horas. Os volumes de água lixiviada foram submetidos à análise por meio de absorção atômica. O desempenho dos corpos de prova tratados em igual condição foi também avaliado quanto à resistência ao ataque de cupins de madeira seca (Cryptotermes brevis). Os resultados obtidos neste trabalho demonstraram que a adição do quaternário graxo amoniacal, não altera alterou significativamente a permanência do octaborato na madeira, mas é importante a continuidade nos estudos dado o aspecto sinergético positivo em relação à prevenção quanto ao ataque de cupins de madeira seca. / With civilizations evolution, the search for practice and durability of materials is a challenge of research and development for new materials and products. The wood preservation as we know today began from second part of XIX century and also is growing and driving forward seeking for new developments. Inside this context, borates are preservatives widely recognized and also are effectives due its appreciable features. Advantageous cost, low environmental impact, large action range put this preservative like a potential product to develop studies towards to reduce its leaching rate. The subject of this work was to verify the possibility of reduce leaching rate of the dissodium octaborate tetrathydratade in Pinus ellioti samples, treated under pressure using tallow ammonium quaternary composition. Were also tested the interference of addiction of tallow ammonium quaternary against the attack of dry-wood termites. Samples of wood were treated for retentions of 2,8 kg/m3 and 4,5 kg/m3 in B2O3 active ingredient, ranging tallow ammonium quaternary proportion from 0,0%, 1,0%, 1,5% and 2,0%. A group of samples was evaluated in leaching test with water collected in intervals 1, 2 and 4 hours. Then, the wood samples were dry at room temperature conditions. After that, the samples returned to leaching and the water was collected after 8, 16 and 48 hours, then all the collected water samples were analyzed by atomic absorption method. Treated at the same conditions, the performance of wood samples we evaluated against dry- wood termites (Cryptotermes brevis). The achieved results in this work demonstrated that addition of tallow ammonium quaternary did not improve octaborate permanence in treated wood; but it is important the studies continuation due the positive synergetic aspect observed with regard to protection against the dry-wood termites attack.
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Transferência de fósforo por escoamento superficial devido à aplicação de água residuária da suinocultura e à adubação mineral em solo com diferentes declividades sob condição de chuva simulada / Transferring phosphorus by surface flow due to swine wastewater application and mineral fertilization on soil with different declivities under simulated rain conditionDieter, Jonathan 13 November 2013 (has links)
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Previous issue date: 2013-11-13 / Swine wastewater application (SWW) in soils under no-tillage system can result in increased levels of phosphorus on soil surface layers, reducing the transferring risk via runoff into the aquatic environment. This trial aimed at evaluating, in two periods of soybean cropping, phosphorus transportation with the drained surface due to SWW application and mineral fertilization (MF) to a soil under no-tillage system with different declivities (i) and submitted to the simulation of different rain intensities (Ip). The trial was carried out on a Eutrophic Red Latosol. The study consisted in applying SWW doses (0, 75, 150, 225 and 300 m3.ha-1) with MF doses of (0%, 25%, 50%, 75% and 100% recommended to the crop) on 0.70 m2 soil plots with different declivities (i) (4, 9, 14, 19 and 24%) followed by the Ip simulation (45, 60, 75, 90 and 105 mm h-1) in two periods just after fertilizer application and seeding (AFAP) and after soybean harvest (ASH). After the runoff, it was simulated the Ip during 72 minutes by collecting independent samples drained solution at intervals of 24 minutes. The concentrations of total phosphorus (Pt), particulate phosphorus (Pp) and soluble phosphorus (Ps) were determined based on the collected samples. The central composite rotational design (CCRD) was used in a complete factorial design 24, with axial points (α = (2n)1/4), totaling 28 essays analyzed as a repeated measure along time. It was observed that concentrations of Pt, Ps and Pp in the runoff solution were positively influenced and showed the following order ARS> i> Ip. The multiple linear regression models adjusted for Ps and Pp concentrations in the runoff solution showed that SWW enhances the Ps transferring to the aquatic environment, while the factors that influence the transportation (i and Ip) showed greater importance in the concentration of transported Pp. During runoff, it was observed that the highest concentrations of Pt, Ps and Pp occurred at the beginning of runoff from the AFAP period, whose Pt concentrations reduced nearly 0.45 mg.L-1 during the ASH period. SWW application enhanced phosphorus transportation through runoff and reached higher concentrations when compared to those established ones by law. Thus, it represents a potential contamination to the environment / A aplicação de água residuária da suinocultura (ARS) em solos sob plantio direto pode resultar no aumento dos teores de fósforo em suas camadas superficiais, a fim de atenuar o risco de transferência via escoamento superficial para o meio aquático. O objetivo do trabalho foi avaliar, em dois períodos da cultura da soja, o transporte de fósforo junto à solução escoada na superfície devido à aplicação de ARS e a adubação mineral (ADM) no solo conduzido em plantio direto com diferentes declives (i) e submetido à simulação de diferentes intensidades de chuva (Ip). O experimento foi conduzido em Latossolo Vermelho eutroférrico. O trabalho consistiu da aplicação de doses de ARS (0, 75; 150; 225 e 300 m3.ha-1) juntamente com doses de ADM (0%, 25%, 50%, 75% e 100% recomendadas para a cultura) sobre parcelas de solo de 0,70 m2 com diferentes declives (i) (4, 9, 14, 19 e 24 %), seguido da simulação da Ip (45, 60, 75, 90 e 105 mm h-1) em dois períodos, logo após aplicação das adubações e semeadura (APA) e após a colheita da soja (APC). Após o início do escoamento superficial, simulou-se a Ip por um período de 72 minutos. Coletaram-se amostras independente da solução escoada em intervalos de 24 minutos. Determinaram-se as concentrações do fósforo total (Pt), fósforo particulado (Pp) e fósforo solúvel (Ps) nas amostras coletadas. Utilizou-se o delineamento composto central rotacional (DCCR), em planejamento fatorial completo 24, com pontos axiais (α =(2n)1/4), totalizando 28 ensaios, analisados como medida repetida no tempo. Observou-se que as concentrações de Pt, Ps e Pp na solução escoada foram influenciadas positivamente e na seguinte ondem ARS>i>Ip. Os modelos de regressão linear múltiplos ajustados sobre as concentrações Ps e Pp na solução escoada demostraram que a ARS potencializa a transferência de Ps para o meio aquático, enquanto os fatores que influenciam no transporte (i e Ip) têm maior importância na concentração de Pp transportado. Durante o escoamento superficial, se observou que as maiores concentrações de Pt, Ps e Pp ocorrem no início do escoamento superficial do período APA, cujas concentrações de Pt foram reduzidas em torno de 0,45 mg.L-1 no período APC. A aplicação de ARS potencializou o transporte de fósforo via escoamento superficial e atingiu concentrações superiores às estabelecidas pela legislação, representando assim um potencial de contaminação ambiental
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Tolerância do pepino enxertado à salinidade em ambiente protegido e controle da salinização do solo. / Salinity tolerance of grafted cucumber in greenhouse and control of soil salinization.Flávio Favaro Blanco 03 February 2000 (has links)
A aplicação de fertilizantes via água de irrigação é prática comum para cultivos em ambiente protegido, o que pode resultar na salinização do solo se o manejo da irrigação não for adequado. Com isso, é de grande importância que se estabeleça a tolerância das culturas à salinidade e o controle eficiente da irrigação para cada cultura a fim de se promover a lixiviação do excesso de sais da zona radicular até um nível tolerado pelas plantas. O presente trabalho teve o objetivo de estabelecer um manejo adequado da fertilização e da irrigação para a cultura do pepino enxertado em ambiente protegido, visando o controle da salinidade do solo, e avaliar métodos de recuperação do solo salinizado. Para isso, foi conduzido um experimento em uma estufa de 110 m 2 para estudar o efeito de diferentes salinidades da água de irrigação (S1=1,58 dS.m -1, S2=3,08 dS.m -1 e S3=5,13 dS.m -1 ), diferentes lâminas de água (L0=1,00.ETc e L1=1,25.ETc) e duas frequências de aplicação da lâmina L1 (F1=em todas as irrigações e F2=quando a lâmina de irrigação acumulada em L0 for igual a 100 mm) no desenvolvimento vegetativo e produção do pepino, cv. Hokushin, enxertado em Cucurbita spp., híbrido Excite-Ikki. O manejo da irrigação foi realizado através de tensiômetros instalados a 15 e 30 cm de profundidade e da evaporação de um tanque reduzido, instalado no interior da estufa. Os resultados obtidos demonstraram que o aumento de uma unidade de salinidade da água de irrigação reduziu a produção total e comercial em 2,83 e 2,99%, respectivamente, não apresentando diferenças significativas. O número de frutos comerciais por planta foi reduzido em 3,32% para cada incremento de uma unidade de salinidade. A salinidade também afetou significativamente a área foliar unitária e o índice de área foliar, bem como a altura e o diâmetro do colo da planta. As diferentes lâminas de irrigação e frequências de aplicação de L1 não resultaram em diferenças significativas para a produção e componentes de produção da cultura. O aumento de uma unidade de salinidade do solo reduziu a produção e o número de frutos por planta, comercial e total, em 7,24 e 6,71% e 8,04 e 7,58%, respectivamente, os quais foram bem inferiores aos valores citados na literatura. A pequena redução na produção e a ausência de diferenças significativas entre os níveis de salinidade não permitiram definir a tolerância do pepino à salinidade e o manejo da lâmina de irrigação quando a água utilizada apresenta alto teor salino. A salinidade do solo aumentou proporcionalmente com o aumento da salinidade da água, sendo que as lâminas de irrigação e as frequências de aplicação de L1 não foram suficientes para reduzir a salinidade do solo, embora a frequência F2 tenha resultado em um aumento mais lento da salinidade. A lixiviação do excesso de sais do solo após o cultivo demonstrou que a aplicação da lâmina de lavagem por gotejamento foi mais eficiente do que a inundação na redução da salinidade do solo. Concluiu-se que a lâmina relativa de lavagem e o valor do coeficiente k a serem utilizados são, respectivamente, de 0,9 e 0,1 para gotejamento e 1,3 e 0,2 para inundação, com base na lâmina calculada pela equação de Rhoades & Loveday (1990). / Fertilizers application through irrigation water is a very common practice for greenhouse cultivation conditions, which can result in the soil salinization if irrigation management is not appropriated. It is very important to establish the crop tolerance to salinity and the efficient irrigation control for each crop to promote leaching of excess salts from the root zone until a tolerated level by plants. The present work had the aim to establish an adapted management of fertilization and irrigation for grafted cucumber cultivated in greenhouse, in order to control the soil salinity, and to evaluate methods of salinized soil reclamation. An experiment has been carried out in a 110 m 2 greenhouse to study the effects of different irrigation water salinity (S1=1,58 dS.m -1 , S2=3,08 dS.m -1 and S3=5,13 dS.m -1 ), different irrigation water depth (L0=1,00.ETc and L1=1,25.ETc) and two applications frequencies of L1 (F1=at every irrigations and F2=when accumulated irrigation water depth in L0 reaches 100 mm) on vegetative development and yield of cucumber, cv. Hokushin, grafted onto Cucurbita spp., hybrid Excite-Ikki. Irrigation management was made by tensiometers installed at 15 and 30 cm deep and by a reduced pan evaporation, installed inside the greenhouse. The results showed that the increment of one unit of irrigation water salinity reduced the total and marketable yield at 2,83 and 2,99%, respectively, not showing significantly reduction. Marketable fruits number per plant was reduced at 3,32% for each increment of one unit of salinity. Salinity also affected significantly the unitary leaf area and the leaf area index, as the height and stem diameter of the plants. The different irrigation water depths and frequencies of L1 application did not result in differences for yield and yield components. Each increment of one unit of salinity reduced yield and fruit number per plant, marketable and total, of 7,24 and 6,71% and 8,04 and 7,58%, respectively, which were smaller than that found on literature. Little reduction in yield and the lack of significantly differences between the levels of salinity did not allow to define cucumber tolerance to salinity and the irrigation management for high salinity irrigation water. Soil salinity increased proportionally to irrigation water salinity increasing, but irrigation water depths and application frequencies of L1 were not sufficient to reduce soil salinity, though the frequency F2 resulted in a slower increasing of soil salinity. Leaching of excess salts after cultivation showed that the application of leaching water depth by drip irrigation was more effective than the application by flooding on soil salinity reduction. We concluded that the relative leaching depth and the k coefficient value to be adopted are, respectively, 0,9 and 0,1 for drip irrigation and 1,3 and 0,2 for flooding, based on water depth calculated by equation of Rhoades & Loveday (1990).
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Estudo exploratório da lixiviação simulada de Cd e Pb presentes em bijuteriasCuvaca, Ana Maria Dores Bernardo 11 May 2017 (has links)
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Previous issue date: 2017-05-11 / Este trabalho teve como objetivo avaliar, usando técnicas espectrométricas a lixiviação de metais de bijuterias em diferentes soluções extratoras. A técnica de espectrometria de massas com fonte de plasma acoplado indutivamente (ICP-MS) foi usada inicialmente para fazer uma varredura nos extratos de quatro soluções para verificar os metais que estavam sendo lixiviados. O planejamento 23 com triplicata no ponto central foi empregado de modo a estudar os parâmetros de lixiviação. Os parâmetros escolhidos foram temperatura (26º C), tempo de 24 h, pH 5,0 (solução 3) e pH 7,5 (solução 1). Após isto, os parâmetros escolhidos foram aplicados para a lixiviação de Cd e Pb em cinco amostras de bijuterias. Amostras de bijuterias de mesmo lote também foram digeridas para a determinação do teor total de Cd e Pb. As soluções resultantes da lixiviação e da digestão das cinco amostras de bijuterias foram analisadas utilizando a técnica de espectrometria de absorção atômica com forno de grafite (GF AAS). As amostras de bijuterias digeridas continham de 1,96 x 10-6 a 3,74 x 10-6 % m/m de Cd e 1,24 x 10-6 a 1,60 x 10-6 % m/m de Pb. Os extratos lixiviados continham de 9,96 x 10-8 a 1,48 x 10-6 % m/m de Cd e <LD a 8,65 x 10-6 % m/m de Pb. Os limites de detecção foram de 2,9 x 10-11 % m/m para Cd e 1,2 x 10-10 % m/m para Pb obtidos por espectrometria de massas com fonte de plasma acoplado indutivamente (ICP-MS); 5,5 x 10-6 % m/m para Cd e 1,9 x 10-5 % m/m para Pb obtidos por espectrometria de absorção atômica com chama (F AAS) e de 2,5 x 10-8 % m/m para Cd e 3,2 x 10-7 % m/m para Pb por espectrometria de absorção atômica com forno de grafite (GF AAS). A curva em meio aquoso foi adequada para as análises, que foi avaliada com estudos de adição e recuperação, em que os valores variaram entre 84-100% e 75-81% para Cd e Pb, respectivamente. Os resultados obtidos pelo método de adição de padrão foram concordantes com os obtidos pela curva externa em 6% para Cd e 0,5 e 1,3 % para Pb nas amostras A e E. Dentre os analitos estudados, o Cd foi o que mais lixiviou e a solução que mais lixiviou foi a solução 1, indicando que este metal se encontrava na forma mais disponível e a possibilidade de ocorrer a lixiviação em soluções com pH entre 6-8. / The aim of this work was to evaluate the leaching of metals in jewelry in different extractive solutions using spectrometric techniques. The inductively coupled plasma mass spectrometry (ICP-MS) technique was initially used to scan the extracts of four solutions to verify the metals being leached. The 23 full factorial design with triplicate at the central point was carried to study the leaching parameters. The parameters chosen were temperature (26 ° C), time of 24 h, pH 5.0 (solution 3) and pH 7.5 (solution 1). After this, the chosen parameters were applied to the leaching of Cd and Pb in five samples of jewelry. Samples of jewelry from the same batch were also digested for determination of the total Cd and Pb content. The solutions resulting from the leaching and digestion of the five jewelry samples were analyzed using the graphite furnace atomic absorption spectrometry (GF AAS). The leached extracts contained from 9.96 x 10-8 to 1.48 x 10 -6 % m/m of cadmium and < LD to 8.65 x 10-6 % m/m of lead. The samples of digested jewelry contained from 1.96 x 10 -6 to 3.74 x 10-6 a % m/m of cadmium and 1.24 x 10-6 to 1.60 x 10-6 % m/m of lead. The limits of detection were 2.9 x 10-11 % m/m for cadmium and 1.2 x 10-10 % m/m for lead in inductively coupled plasma mass spectrometry (ICP-MS), 5.5 x 10-6 % m/m for cadmium and 1.9 x 10-5 % m/m for lead (F AAS) and 2.5 x 10-8 % m/m for cadmium and 3.2 x 10-7 % m/m for lead in the graphite furnace atomic absorption spectrometry (GF AAS). The curve in aqueous medium was suitable for the analyses, which was evaluated with addition and recovery studies, where values varied between 84-100% and 75-81% for cadmium and lead, respectively. The results obtained by standard addition were similar with those obtained by the calibration curve in 6 % for cadmium and 0.5 and 1.3 % for lead in samples A and E. Among the analyzed analytes, the Cd was the one more leached and the solution that leached more metals was solution 1, indicating that this metal was in the most available form and the possibility of leaching occurred in solutions with pH between 6-8.
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Condutividade elétrica em diferentes partes de sementes de soja / Electrical conductivity inin different parts of soybean seedsCunha, Cristina dos Santos Madruga 30 September 2010 (has links)
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Previous issue date: 2010-09-30 / Among the rapid tests, the electrical conductivity has been used for
the evaluation of seed vigor, since the process of deterioration of the initial
events is the loss of membrane integrity. The objective was to evaluate the
efficiency of electrical conductivity mass and individual, driven to different
parts of soybean seeds (whole seed, cotyledons and embryonic axes) and
verify the possibility of obtaining results in less than 24 hours. The electrical
conductivity and mass were conducted in individual laboratories Didactic
Analysis of Seed Plant Science Department, Faculty of Agronomy "Eliseu
Maciel (UFPel) and Universidade Federal de Santa Maria (UFSM),
respectively. We used seeds of two cultivars, each represented by six lots.
The physiological seed quality was evaluated by standard germination, first
count germination, seedling vigor classification, accelerated aging, a field
emergence and electrical conductivity. To conduct the electrical conductivity
mass of the different structures of the seed, there were four replicates of each
batch, with 10 whole seeds, embryonic axes 10 and 10 pairs of cotyledons
submerged in 25mL of distilled and deionized water for the following periods:
1, 2 , 3, 4, 5, 6, 7, 8 and 24 hours. As the system mass, electrical conductivity
of the different structures of the individual seed, there were four replicates of
each batch. Whole seeds were submerged in 5mL of distilled and deionized
water for 24 hours as well as the embryonic axes and cotyledons pairs of the
following periods: 1, 2, 3, 4, 5 and 6 hours. The electrical conductivity test
conducted with embryonic axes mass is promising for evaluating the effect of
soya, showing efficiency in the stratification of lots with respect to physiological
potential; The effect of soybean seeds can be determined by electrical
conductivity mass, using 10 embryonic axes immersed in 25mL of deionized
water and imbibed for one hour at 25 ° C. / Dentre os testes rápidos, o de condutividade elétrica tem sido
bastante utilizado para a avaliação do vigor das sementes, uma vez que no
processo de deterioração um dos eventos iniciais é a perda da integridade
das membranas celulares. O objetivo do trabalho foi avaliar a eficiência dos
testes de condutividade elétrica massal e individual, conduzidos com
diferentes partes de sementes de soja (semente inteira, cotilédones e eixos
embrionários) e verificar a possibilidade de obter resultados em tempo inferior
a 24 horas. Os testes de condutividade elétrica massal e individual foram
conduzidos nos Laboratórios Didáticos de Análise de Sementes do
Departamento de Fitotecnia da Faculdade de Agronomia Eliseu Maciel
(UFPel) e do Departamento de Fitotecnia do Centro de Ciências Rurais da
Universidade Federal de Santa Maria (UFSM), respectivamente. Foram
utilizadas sementes de duas cultivares, cada uma representada por seis lotes.
A qualidade fisiológica das sementes foi avaliada pelo testes de germinação,
primeira contagem de germinação, classificação do vigor de plântulas,
envelhecimento acelerado, emergência em campo e condutividade elétrica.
Para condução do teste de condutividade elétrica massal das diferentes
estruturas da semente, foram utilizadas quatro repetições de cada lote, com
10 sementes inteiras, 10 eixos embrionários e 10 pares de cotilédones
submersos em 25mL de água destilada e deionizada pelos períodos de 1, 2,
3, 4, 5, 6, 7, 8 e 24 horas. Assim como no sistema massal, na condutividade
elétrica individual das diferentes estruturas da semente, foram utilizadas
quatro repetições de cada lote. Sementes inteiras foram submersas em 5mL
de água destilada e deionizada por 24 horas, assim como os eixos
embrionários e pares de cotilédones pelos períodos de 1, 2, 3, 4, 5 e 6 horas.
O teste de condutividade elétrica massal conduzido com eixos embrionários é
promissor para a avaliação do vigor de sementes de soja, mostrando
eficiência na estratificação de lotes quanto ao potencial fisiológico; O vigor de
sementes de soja pode ser determinado pelo teste de condutividade elétrica
massal, utilizando 10 eixos embrionários com imersão em 25mL de água
deionizada e tempo de embebição de uma hora, a 25ºC.
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FUNCTIONALIZATION OF SILVER NANOPARTICLES ON MEMBRANES AND ITS INFLUENCE ON BIOFOULINGSprick, Conor G. 01 January 2017 (has links)
Ultrafiltration (UF) processes are often used as pretreatment before more retentive/costly processes, such as nanofiltration and reverse osmosis. This study shows the results of low-biofouling nanocomposite membranes, loaded with casein-coated silver nanoparticles (casein-Ag-NPs). Membranes were cast and imbedded with Ag-NPs using two approaches, physical blending of Ag-NPs in the dope solution (PAg-NP/CA membranes) and chemical attachment of Ag-NPs to cast membranes (CAg-NP/CA membranes), to determine their biofouling control properties. The functionalization of Ag-NPs onto the CA membranes was achieved via attachment with functionalized thiol groups with the use of glycidyl methacrylate (GMA) and cysteamine chemistries. The immobilization chemistry successfully prevented leaching of silver nanoparticles during cross-flow studies. Pseudomonas fluorescens Migula in brackish water was used for short-term dead-end filtration, where CA and CAg-NP/CA membranes displayed lower flux declines as compared to PAg-NP/CA membranes. In subsequent long-term biofouling studies, also with Pseudomonas fluorescens Migula in brackish water with addition of sodium acetate, chemically-attached Ag-NPs led to a significant reduction in the accumulation of bacterial cells, likely due to the more dispersed nanoparticles across the surface. Therefore, a method was developed to chemically immobilize Ag-NPs to membranes without losing Ag-NP’s antimicrobial properties.
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Temporal and spatial variation in the status of acid rivers and potential prevention methods of AS soil-related leaching in peatland forestrySaarinen, T. (Tuomas) 14 May 2013 (has links)
Abstract
This thesis examines temporal and spatial variations in the status of different rivers and streams of western Finland in terms of acidity and sources of acid load derived from the catchment area. It also examines the monitoring of acid runoff water derived from maintenance drainage in peatland forestry and suggests potential mitigation methods.
A total of 17 river basins of different sizes in western Finland were selected for study, including rivers affected by both drainage of agricultural AS soils and forested peatlands. Old data from 1911–1931 were available, but most data were from the 1960s onwards and were taken from the HERTTA database. During 2009–2011, pH and conductivity measurements and water sampling were conducted. Biological monitoring for ecological classification was conducted in the Sanginjoki river system during 2008 and 2009. Three peatland forestry sites were selected to study acid leaching via pH and EC measurements and water sampling. Fluctuations in groundwater level in different drainage conditions were simulated and acid leaching was investigated in laboratory experiments in order to replicate a situation where the groundwater level drops and allows oxidation of sulphidic materials.
It was found that river pH decreased and metal concentrations increased with runoff. The highest acidity observed coincided with periods of intense drainage in the 1970s and after dry summers in the past decade. Together with pH, electric conductivity and sulphate in river water were identified as suitable indicators of AS soils in a catchment, because they directly respond to acid leaching derived from AS soils. Acidity derived from organic acids was clearly observed in catchments dominated by forested peatlands and wetlands. Temporal and spatial variations in ecological status were observed, but monitoring at whole-catchment scale and during consecutive years is needed to increase the reliability of the results.
Simulations on the potential effects of maintenance drainage in peatland forestry on runoff water quality showed a clear risk of oxidation of sulphidic materials during dry summers. This can be prevented mainly by avoiding too deep drainage. Knowledge of the hydrochemical impacts of acidic load derived from AS soils and drained peatlands is necessary for land use planning and sustainable water management of river basins affected by these soils. / Tiivistelmä
Tutkimuksessa tarkastellaan Suomen länsirannikon happamuudesta kärsivien jokivesistöjen tilan ajallista ja paikallista vaihtelua. Tutkimuskohteena on sekä happamien sulfaattimaiden että ojitettujen turvemaiden jokivesistöjä. Tutkimuksessa tarkastellaan myös sulfidipitoisilta metsäojitetuilta turvemailta valuvaa happamuutta sekä ehdotetaan tällaisille kohteille soveltuvia keinoja huuhtouman ehkäisemiseksi.
Tutkimukseen valittiin 17 erikokoista jokivesistöä, joiden valuma-alueella on sekä happamia sulfaattimaita että metsäojitettuja turvemaita. Varhaisin väitöskirjaan sisällytetty aineisto on vuosilta 1911–1931. HERTTA-tietokannasta poimittiin aineistoa happamuusmuuttujista 1960-luvulta alkaen. Vuosina 2009–2011 suoritettiin pH- ja sähkönjohtavuusmittauksia sekä otettiin vesinäytteitä Siika- ja Pyhäjoen valuma-alueen joista sekä näiden välissä sijaitsevien pienempien valuma-alueiden joista. Ekologisen tilan selvittämiseksi otettiin biologiset näytteet Sanginjoen valuma-alueen joista ja puroista vuosien 2008 ja 2009 aikana. Kunnostusojituskohteilla seurattiin pH:n ja sähkönjohtavuuden muutoksia kokoojaojissa sekä otettiin vesinäytteitä. Pohjaveden pinnan vaihtelua selvitettiin sekä kenttämittauksilla että mallinnuksen avulla. Laboratoriokokeen avulla selvitettiin sulfidien hapettumista.
Metallipitoisuudet nousivat ja pH laski valumien kasvaessa. 1970-luvulla toteutetut salaojitukset heijastuivat jokien happamuuden kasvuna. Myös viime vuosikymmenen kuivat kesät näkyivät veden happamuuden lisääntymisenä syksyn ylivirtaamatilanteissa. Veden pH, sähkönjohtavuus sekä sulfaatti ilmensivät happamien sulfaattimaiden esiintymistä valuma-alueella. Orgaanisista hapoista peräisin olevaa happamuutta havaittiin valuma-alueilla, joilla on runsaasti ojitettuja turvemaita. Ekologisen tilan ajallisen ja paikallisen vaihtelun vuoksi seurantaa tulisi toteuttaa peräkkäisinä vuosina sisällyttäen tarkasteluun valuma-alueen eri jokia ja puroja.
Kunnostusojitukset voivat aiheuttaa happamuutta, jos ojitus ulottuu sulfidikerrokseen. Riski on olemassa poikkeuksellisen kuivina kesinä. Sulfidien hapettumista voidaan ehkäistä välttämällä liian syvien ojien kaivamista. Maatalouskäytössä olevilta happamilta sulfaattimailta ja ojitetuilta turvemailta peräisin olevan huuhtouman vaikutukset tulee tuntea, jotta valuma-alueiden maankäyttöä ja vesiensuojelua voidaan toteuttaa tehokkaasti.
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Assessing industrial pollution by means of environmental samples in the Kemi-Tornio regionPöykiö, R. (Risto) 29 November 2002 (has links)
Abstract
The results of the comparison of various dissolution methods for sulphur showed, that HNO3 together with
H2O2 gave more complete decomposition of organic components than HNO3
alone. The acid procedure with a mixture of HNO3+H2O2 slightly
underestimated the S concentrations of plant material. The losses of sulphur were the highest in the dry ashing digestion procedure
(HF(DAC)). The Leco combustion technique with infrared (IR) detection gave good precision and accuracy for sulphur. For the determination
of heavy metals in plant materials, both the HNO3 and
HNO3+H2O2 procedures were especially effective for determining Cr.
However, the HNO3+HClO4 procedure gave lower results, and HF and HF(DAC) procedures greater
values for Cr.
Sulphur accumulation in pine needles around the pulp and paper mills was clearly higher than other points in the Kemi area. For
example, within a radius of about 1-1.5 km around the mills of Oy Metsä-Botnia Ab Kemi Mills, the sulphur concentrations for (C) and
(C+1) needles were 28 % and 26 % higher than those in the corresponding background samples collected in Kuivaniemi at a distance about 25
km from Kemi. Pine needles do not appeared to be appropriate a method for monitoring the accumulation of Fe, Zn, V and Pb emitted from pulp
and paper mills. However, the Ca concentrations in (C+1) needles in the vicinity of the Oy Metsä-Botnia Ab Kemi Mills was 48 % higher
than
the average Ca concentration calculated from all (C+1) needles; thus it is likely that part of the Ca in the needles is derived from the
mills.
The regional distribution pattern of Cr and Ni in mosses in the Kemi-Tornio area in 2000 showed clearly that the most polluted area
(Cr > 200 μg/g and Ni > 20 μg/g) appeared to lie within a few kilometres of the ferrochrome and stainless steel works of
AvestaPolarit Stainless Oy. Within this area, the Cr concentrations in mosses were 4-13 times higher than those outside the urban area of
Tornio. The area most polluted by the opencast chromium mining complex (Cr > 200 μg/g and Ni < 20 μg/g) appeared to be in
the immediate vicinity of complex.
All the 95th percentile values for TSP (total suspended particles) in the mine area of AvestaPolarit
Chrome Oy Kemi Mine were below the current Finnish air quality limit value of 300 μg/m3. However, the
98th percentile value exceeded the Finnish air quality guideline value of 120
μg/m3 at one monitoring site.
According to leaching studies, the sum of calculated annual airborne pollution impact of water-soluble fraction
(H2O) and environmentally mobile (CH3COONH4) fraction from the
AvestaPolarit Chrome Oy Kemi Mine was Cr 1.2 kg, Fe 29 kg, Cu 63 kg, Ni 2.5 kg and Cd < 100 mg.
According to the homogeneity studies of heavy metal deposition on TSP filters, Cr, Ni, Cu and Fe were non-uniformly distributed over
the glass fibre filters. The rsd values varied between 5.4-33.9 % for Cr, between 7.5-35.0 % for Ni, between 3.6-25.9 % for Cu, and between
6.6-19.9 % for Fe.
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Leaching and recovery of molybdenum, nickel and cobalt from metals recycling plants mineral sludges / Lixiviation et récupération du molybdène, du nickel et du cobalt à partir des boues minérales générées par une usine de recyclage métallurgiqueVemic, Mirjana 26 October 2015 (has links)
Compte tenu de l'épuisement en cours des ressources naturelles qui ont lieu dans le monde entier, le prix élevé, la forte demande et la pénurie future des ressources minérales primaires pour Mo, Ni et Co, il est extrêmement important de mettre en œuvre le recyclage des métaux/récupération/réutilisation partir des demi-finis produits, sous-produits, des matériaux secondaires et des déchets, y compris les déchets dangereux (ce est à dire des catalyseurs usés, boues minérales). En outre, il est nécessaire d'utiliser des technologies plus efficaces pour récupérer des métaux à partir de déchets/ressources secondaires afin de minimiser les dépenses en capital, l'impact environnemental et de répondre à l'augmentation de la demande de métal. Parmi les différentes ressources secondaires, les catalyseurs usés et les boues minérales générés aux catalyseurs usés usines de recyclage pourrait être une très bonne ressource secondaire, car ils contiennent des concentrations élevées de métaux différents (en particulier Mo, Ni et Co). Par conséquent, ils doivent être considérés comme une ressource et non comme un déchet. Dans notre étude, nous traitons avec le catalyseur, l'oxyde métallique et le recyclage des piles minérales de la plante boues. Ce type de matériau contient de fortes concentrations de métaux différents. Cependant, au mieux de nos connaissances de spéciation, lixiviation et de récupération des propriétés de ce type de matériel n'ont pas été étudiés auparavant. Boues minérales a été minutieusement caractérisée où le pH, La perte au feu (LOI), Toxicité Caractéristique Lixiviation Procédure (TCLP), Diffraction des rayons X (XRD), Microscopie électronique à balayage (SEM) avec dispersion d'énergie des rayons X spectroscopie (EDS), Total Métal Contenu (TMC) et Extraction Séquentielle (SE) ont été effectuées. Sur la base des résultats de la caractérisation des boues minérales, le taux de lixiviation et les rendements de Mo, Ni et Co à partir de l'échantillon de boue minérale ont été quantifiés. Différents réactifs de lixiviation (autonome acides (nitrique, sulfurique et chlorhydrique) et les mélanges d'acides (eau régale (nitrique + chlorhydrique (1:3)), nitrique + sulfurique (1:1) et nitrique + sulfurique + chlorhydrique (2:1:1)) ont été étudiés à changer les paramètres de fonctionnement (solides ratio liquide, le temps de lixiviation et de la température), afin de comprendre les caractéristiques de lixiviation et sélectionnez le réactif de lixiviation approprié qui permet d'atteindre les plus hauts rendements de lixiviation de métal. Acide sulfurique (H2SO4) a été trouvé d'être le produit de lixiviation avec le potentiel de lixiviation des métaux les plus élevés. Les conditions de lixiviation optimales étaient une lixiviation en trois étapes successives, la température de 80°C, le temps de lixiviation 2 h, et S/L rapport 0.25 g L-1. Dans ces conditions, les rendements de lixiviation à partir de notre échantillon de boue minérale a atteint 85.5, 40.5 et 93.8% pour Mo, Ni et Co, respectivement / In view of the on-going depletion of the natural resources taking place worldwide, the high price, high demand and future shortage of the primary mineral resources for Mo, Ni and Co it is extremely important to implement metals recycling/recovery/reuse from semi-finished products, by-products, secondary materials and wastes, including hazardous waste (i.e. spent catalysts, mineral sludges). Furthermore, there is a need to utilize more efficient technologies to recover metals from wastes/secondary resources in order to minimize capital outlay, environmental impact and to respond to the metal increased demand. Among the different secondary resources, spent catalysts and mineral sludges generated at the spent catalysts recycling plants could be a very good secondary resource, as they contain high concentrations of different metals (especially Mo, Ni and Co). Therefore, they should be viewed as a resource, not as a waste. In our study we are dealing with the catalyst, metallic oxide and battery recycling plant mineral sludge. This type of material contains high concentrations of different metals. However, to the best of our knowledge, speciation, leaching and recovery of Mo, Ni and Co from this type of material were not investigated before. Mineral sludge was minutely characterized where pH, Loss On Ignition (LOI), Toxicity Characteristic Leaching Procedure (TCLP), X-ray Diffraction (XRD), Scanning Electron Microscopy (SEM) with Energy Dispersive X-ray Spectroscopy (EDS), Total Metal Content (TMC) and Sequential Extraction (SE) were performed. Based on the mineral sludge characterization results the leaching rate and yields of Mo, Ni and Co from mineral sludge sample were quantified. Different leaching reagents (stand-alone acids (nitric, sulfuric and hydrochloric) and acid mixtures (aqua regia (nitric + hydrochloric (1:3)), nitric + sulfuric (1:1) and nitric + sulfuric + hydrochloric (2:1:1)) were investigated at changing operational parameters (solid to liquid ratio, leaching time and temperature), in order to understand the leaching features and select the suitable leaching reagent which achieves the highest metal leaching yields. Sulfuric acid (H2SO4) was found to be the leachant with the highest metal leaching potential. The optimal leaching conditions were a three stage successive leaching, temperature 80°C, leaching time 2 h and S/L ratio 0.25 g L-1. Under these conditions, the leaching yields from our mineral sludge sample reached 85.5, 40.5 and 93.8% for Mo, Ni and Co, respectively
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