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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
11

Thermodynamic Equilibrium Prediction of Corrosion Tendency in Fluidized-Bed Combustion of Solid Waste

Hosseinian, Aida January 2017 (has links)
Global warming and air pollution are two issues of greatest concerns to human life in recent years. Environmental concerns and econimal/political independency of fossil fuels have been the driving force of developing interest in renewable resources of energy for many countries. Different type of waste-derived fuels such as biomass, municipal solid waste and industrial waste are interesting energy resources for energy producing companies. There are mainly two main paths when it comes to waste-to-energy industry, which are thermal treatment of waste, as well as biochemical treatment. Thermal treatment of waste to produce energy could benefit both for hygienic consideration of waste management and avoiding waste landfill.Heat and power generation through combustion of waste or biomass has several environmental, and economical advantageous over utilization of fossil fuels. Thermal conversion of waste and biomass fuels, however, has some challenges mainly due to their chemical composition and high alkali metals (potassium and sodium) content. Combustion of these fuels usually can result in some operational challenges such as deposition, fouling, bed agglomeration and corrosion in different part of the boiler. The less reactive and non-combustible part of the fuel known as ash-forming matter has a major role in these operational challenges. Ash related problems in waste-to-energy boilers lead to lower efficiency, high maintenance costs and equipment failure. Therefore, investigating the chemical composition of fuel and ash-forming matter is essential prior to thermal conversion of waste-derived fuels. High-temperature corrosion due to formation of corrosive alkali chloride compounds during combustion is one of the main ash-related concerns in boilers.This study investigated high-temperature corrosion in circulating fluidized-bed (CFB) combustion of solid waste. Flue gas composition of solid waste combustion in the CFB boiler was analysed in two cases: combustion of the reference fuel, and combustion of the “same” fuel with a sulphur containing additive (ammonium sulphate), to decrease the corrosive alkali chlorides in the flue gas. Chemical fractionation was carried out for fuel samples to determine the reactive and less-reactive fraction of ash-forming matter. A thermodynamic equilibrium model was developed using Factsage thermochemical software, to predict the chemical composition of the flue-gas with a special focus on corrosive alkali chlorides. The modelling results were evaluated using In-situ Alkali Chloride Monitoring (IACM) results obtained during the full-scale combustion measurements.
12

An investigation of some properties of Shredder Fines and an element analysis of its ash to find new ways of dealing with this waste / En undersökning av vissa egenskaper hos fragmenteringsrester och en elementanalys av dess aska för att hitta nya sätt att hantera detta avfall

Naidoo, Adeel January 2020 (has links)
Shredder fines are the materials with a particle size of less than 10 mm resulting from the shredding of vehicles and complex metal scrap from industries and municipalities. This waste is currently used as landfill construction material, but Stena Recycling wanted to know whether the bottom ash from the combustion of this waste could be useful to the cement industry, and whether it would be feasible to extract Cu and Zn from this ash. To determine this the shredder fines were combusted, and the generated bottom ash underwent chemical fractionation. The leachates from this were processed using MP-AES to obtain an elemental analysis of the ash. The uncombusted shredder fines had its moisture content and calorific value determined. The shredder fines had a moisture content of approximately 11%wt. Due to the heterogeneity of the shredder fines the calorific values varied significantly across the tested samples. The average value was 7.8 MJ/kg. The chemical fractionation showed that the elements in the ash are mostly insoluble in water and ammonium acetate, as the majority remained in the solid residue. This indicates that the ash is inert, and not susceptible to heavy metal leaching. The elemental analysis showed that there is a significant amount of Fe in the ash, with reasonable amounts of Cu and Zn. This project concluded that without additional processing the ash would not be suitable for the cement industry, and that there is potential for the recovery of Cu and Zn from the ash.
13

Effects of Reduced-Bed Temperature on Volatilization of Inorganic Components during Combustion of Municipal Solid Wastes in Fluidized Bed Boilers

Moradian, Farzad January 2010 (has links)
No description available.
14

Formas de fósforo no tecido de videiras: acúmulo, redistribuição e relação com parâmetros produtivos e composição da uva / Phosphorus fractions in the grapevines tissue: accumulation, redistribution and relationship with parameters productive and composition grape

Piccin, Rogério 29 July 2016 (has links)
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / In grapevine production, requirement and phosphorus (P) doses are established on the basis total P content in leaves collected, change in color of fruit and productivity. Phosphorus absorbed, can be accumulated in plant organs in organic forms as metabolically active organic P in the cytoplasm (PSO), phospholipids (PLIP), P associated with RNA and DNA (PRNA and PDNA), phosphoprotein (PRES) and inorganic P (PSI). However, in adult grapevine, production is not known satisfactorily that increase in available P content in soil can enhance P in leaves and other annual and perennial parts of plant collected at different growth stages. The study was aimed to quantify the accumulation and redistribution of P forms in grapevine throughout its production cycle and evaluate the forms of P in leaves related to production parameters and grape composition. Two experiments were performed in vineyard 1 (V1) and vineyard 2 (V2) containing 11,8 and 34,6 mg P kg-1 of soil respectively with two cultivars of grapevine Tannat and Cabernet Franc. The plants were uprooted and separated into roots, stems, branches, groins, shoots, and leaves and flowering (F), early maturation (EM), harvest (H) and dormant (D) and each plant part was analyzed for P fractions (PSI, PSO, PLIP, PRNA, PDNA and PRES). Study 2 consisting of two experiments was conducted vineyard 1 (V1) and vineyard (V2) with 16,0 and 37,0 mg P kg-1 of soil to evaluate whether P forms in leaves collected in the F and EM are related to productive and enological parameters in vines grown on soils with values of available P in both cultivars Tannat and Cabernet Franc. At harvest, production parameters, number of fruits (FN) and 100 fruits weight (FW) were measured. Part of the grapes were crushed by hand and must was analyzed the total soluble solids (TSS), pH, titratable acidity (TA), total polyphenols (PF) and anthocyanins (AC). Results from study 1 show that grapevines P is preferentially accumulated in the form PSI in the leaves and bunches at F, EM and H and roots in PSO way in D. Part PSI roots is redistributed on the FL to the leaves and grapes vines grown in soil with low P availability, but on the other hand, grapevines grown in soil with high availability of P tend to redistribute least PSI from roots to leaves and bunches after F. In study 2, we found that grapevines grown in soil with high P content available soil have higher PT Tannat grapevines and higher levels of total polyphenols and anthocyanins. The total P content in leaves and their biochemical forms in leaves collected in the F and M have no relation to production parameters. But total P content in leaves at flowering and early maturation has relationship with the AC content in the Tannat grapevines. / Na adubação de produção de videiras a necessidade e a dose de fósforo (P) é estabelecida com base no teor de P total em folhas coletadas na mudança da cor das bagas e na expectativa de produtividade. O P absorvido pode ser acumulado em órgãos da planta em formas orgânicas como o P orgânico metabolicamente ativo no citoplasma (PSO), fosfolipídios (PLIP), P associado ao RNA e DNA (PRNA e PDNA), fosfoproteínas (PRES) e P inorgânico (PSI). Porém, em videiras adultas em produção não é suficientemente conhecido se o incremento do teor de P disponível no solo pode alterar a distribuição de formas de P em órgãos anuais e perenes ao longo de estágios fenológicos, assim como se as formas de P em folhas, coletadas em diferentes estágios fenológicos, podem ter relação com parâmetros produtivos e enológicos do mosto. O presente trabalho objetivou quantificar o acúmulo e a redistribuição de formas de P em videiras em produção ao longo do seu ciclo e avaliar se as formas de P em folhas possuem relação com parâmetros produtivos e composição do mosto. Foram conduzidos dois estudos. O Estudo 1 foi realizado para estimar a distribuição e redistribuição de formas de P em videiras cultivadas em solos com diferentes teores de P disponível. Os tratamentos foram vinhedo 1 (V1) com 11,8 mg P kg-1 disponível no solo e vinhedo 2 (V2) com 34,6 mg P kg-1. As videiras foram arrancadas e particionadas em raízes, caules, braços, esporões, ramos do ano, folhas e cachos, no florescimento (FL), início da maturação (IM), colheita (CO) e repouso vegetativo (RV). Os órgãos foram submetidos ao fracionamento químico de P, que estima as formas: PSI, PSO, PLIP, PRNA, PDNA e PRES. O Estudo 2 foi realizado para avaliar se formas de P em folhas coletadas no FL e IM possuem relação com parâmetros produtivos e enológicos em videiras cultivadas em solos com teores de P disponível. Esse foi composto por dois experimentos. O experimento 1 foi realizado em dois vinhedos (V1 e V2) da cultivar Tannat. O solo do V1 continha 11,8 mg P kg-1 e solo do V2 possuía 34,6 mg P kg-1. O experimento 2 foi realizado em dois vinhedos (V1 e V2) da cultivar Cabernet Franc. O solo do V1 continha 16,0 mg P kg-1 e V2 possuía 37,0 mg P kg-1. No FL e IM foram coletas folhas completas e submetidas ao fracionamento de P no tecido. Na colheita foi determinada a produtividade (PT), contado o número de bagas (NB) e determinado o peso de 100 bagas (PB). Parte das bagas foram amassadas manualmente e no mosto foi analisado os sólidos solúveis totais (SST), pH, acidez total titulável (AT), polifenóis totais (PF) e antocianinas totais (AC). Os resultados obtidos no Estudo 1 mostram que em videiras o P é acumulado preferencialmente na forma PSI nas folhas e cachos no FL, IM e CO, e nas raízes na forma PSO, no RV. Parte do PSI das raízes é redistribuído no FL para as folhas e cachos em videiras cultivadas em solo com baixa disponibilidade de P, mas, por outro lado, videiras cultivadas em solo com alta disponibilidade de P tendem a redistribuir menos PSI das raízes para as folhas e cachos após o FL. No estudo 2, verificamos que videiras cultivadas em solo com alto teor de P disponível no solo possuem maior produtividade de uvas, e videiras Tannat possuem maiores teores de polifenóis totais e antocianinas. O teor de P total em folhas e suas formas bioquímicas em folhas coletadas no FL e no IM não possuem relação com parâmetros produtivos. Mas, o teor de PTOTAL em folhas no florescimento e início da maturação possui relação com o teor de AC no mosto em videiras Tannat.
15

Cobre em solos arenosos sob vinhedos e reposta bioquimicafisiológica de videiras em produção / Copper in vineyards sandy soils and response biochemicalphysiological of the grapevine in productive season

Miotto, Alcione 20 December 2012 (has links)
Conselho Nacional de Desenvolvimento Científico e Tecnológico / The use of Cu-based fungicides in the cultivation of grapevines for controlling fungal diseases results in excessive accumulation of Cu in soils, which may cause nutritional problems to plants. The present work aimed to investigate the accumulation and forms of Cu in acid sandy soils cultivated with vineyards in the Campanha Gaúcha region and the biochemical and physiological responses of grapevines in productive season. The study was conducted from 2009 to 2011 in the vineyards of the cultivar Cabernet Sauvignon, grown in the Campanha Gaúcha region, municipality of Sant Ana do Livramento, RS. First, the total (CuT) and available (CuEDTA) concentration of Cu were assessed in 19 vineyards at different ages and historic of applications of Cu-based fungicides. In addition, assessments were carried out for the vertical distribution of CuT and CuEDTA, the amount of accumulated CuT per hectare and the forms of Cu in the soil (chemical fractionation) in three vineyards aged 5, 11 and 31 years of cultivation. A soil collected from an area under natural field, near the vineyards, was used for comparison purposes. In the second part of the study, concentration and accumulation of Cu in the organs of the grapevines and the concentrations of macronutrients and biochemical parameters in leaf blades were investigated in vineyards grown in soils with increasing Cu concentrations. Tissue samples were collected from vines in the 2009/2010 and 2010/2011 vegetative cycles, at various phenological stages, before and after the application of Cu-based fungicides. The results reveal that the vineyards aged over 25 years of cultivation presented average concentrations of 90 mg kg-1 of CuT in the surface layer of the soil. Approximately 77% of the total Cu accumulated in the soil is CuEDTA, and thus potentially available to plants. The main form of accumulation of Cu in the soils of the vineyards was related to the mineral fraction (bound to iron and manganese oxides), which represented 75% of CuT, followed by the organic matter that complexes only 20% of the total. No significant changes were observed in the residual fraction of Cu, with higher bond strength, which indicates the prevalence of potentially available forms. In the grapevines, increased Cu concentrations were observed in leaves, as well as evidence of oxidative stress, which were correlated with increased concentrations of Cu in soil. However, the increased availability of Cu in soils slightly affects the concentrations and content of Cu in grapevines in productive season and does not change their nutritional status. The use of Cu-based fungicides is the main determinant of increased concentration of Cu in annual organs of grapevines, especially leaves and rachis, but the residue of Cu in the berries is not related to the amount applied to the element. / No cultivo de videiras, o uso de fungicidas cúpricos para o controle das doenças fúngicas causam o acúmulo excessivo de Cu em solos, o que pode provocar alterações nutricionais às plantas. O trabalho objetivou estudar o acúmulo e formas de Cu em solos arenosos e de carácter ácidos cultivados com vinhedos na região da Campanha Gaúcha do Rio Grande do Sul e as respostas fisiológico-bioquímicas de videiras em produção. O estudo foi realizado nos anos de 2009 a 2011 em vinhedos da cultivar Cabernet Sauvignon cultivados na região da Campanha Gaúcha, município de Sant Ana do Livramento, RS. Primeiramente foram investigados os teores de Cu total (CuT) e disponível (CuEDTA) em 19 vinhedos com diferentes idades e históricos de aplicações de fungicidas a base de Cu. Além disso, também investigouse a distribuição vertical de CuT e CuEDTA, a quantidade de CuT acumulado por hectare e as formas de Cu no solo (fracionamento químico) em três vinhedos com 5, 11 e 31 anos de cultivo. Um solo coletado em uma área sob campo natural, próximo aos vinhedos, foi utilizado para fins de comparação. Na segunda parte do estudo foram avaliados os teores e acúmulo de Cu nos órgão das videiras e teores de macronutrientes e parâmetros bioquímicos em limbos foliares em vinhedos cultivados em solos com teores crescentes de Cu. As amostras de tecidos das videiras foram coletadas nos ciclos vegetativos 2009/2010 e 2010/2011, em vários estádios fenológicos, antes e também após a aplicação de fungicidas a base de Cu. Os resultados mostras que os vinhedos com mais de 25 anos de cultivo apresentaram teores médios de 90 mg kg-1 de CuT na camada superficial do solo. Do total de Cu acumulado nos solos, aproximadamente, 77% é CuEDTA, sendo portanto, potencialmente disponível para as plantas. A principal forma de acúmulo de Cu nos solos dos vinhedos foi ligada à fração mineral (ligados aos óxidos de ferro e manganês), que representou 75% do CuT, seguido pela matéria orgânica que complexa apenas 20% do total. Não foram observadas alterações importantes na fração residual de Cu, de maior força de ligação, o que indica a prevalência de formas potencialmente disponíveis. Nas videiras foram observados incrementos nos teores de Cu nas folhas e evidência de estresse oxidativo que foram correlacionados com o aumento dos teores de Cu no solo. Contudo, o aumento da disponibilidade de Cu nos solos pouco afeta os teores e o acúmulo de Cu em videiras em produção e não altera seu estado nutricional. O uso de fungicidas a base de Cu é o principal fator determinante do aumento dos teores de Cu nos órgãos anuais das videiras, especialmente, nas folhas e ráquis, mas o resíduo de Cu nas bagas não está relacionado à quantidade aplicada do elemento.
16

Estudo alelopático de espécies da família Myrtaceae do cerrado

Imatomi, Maristela 20 December 2010 (has links)
Made available in DSpace on 2016-06-02T19:29:31Z (GMT). No. of bitstreams: 1 3411.pdf: 2299382 bytes, checksum: 44ff227a0e9cd4657b1aca56caa5179c (MD5) Previous issue date: 2010-12-20 / Universidade Federal de Sao Carlos / The plants release primary and secondary metabolites in the environment that may influence the development of adjacent vegetation, this interference phenomenon is called allelopathy. It is recognized as an important ecological process because it interferes with the structure, distribution, composition and dynamics of plant communities. Studies on allelopathic interactions may be useful in the search for natural phytotoxins are produced by plants or microorganisms to be used as natural herbicides, more specific and less harmful to the environment. According to floristic survey conducted by IBGE, Myrtaceae family is one of the major in the cerrado ecosystem. This study attempted to clarify the following issues: species of Myrtaceae family present in the cerrado (Brazilian savanna) exhibit allelopathic potential? There is a similar allelopathic response within genera? Among the active species, which is most promising for starting a bioprospecting? Some of these species has potential as a herbicide for use in agroforestry or organic production of food? To answer these questions were conducted experiments of seed germination and seedling growth of target species cultivated and weedy, and chemical extraction of active compounds in leaves of Myrcia tomentosa. The leaves of Blepharocalyx salicifolius, Campomanesia pubescens, Eugenia bimarginata, Eugenia klotzschiana, Eugenia myrcianthes, Eugenia punicifolia, Myrcia bella, Myrcia lingua, Myrcia multiflora, Myrcia splendens, Myrcia tomentosa, Psidium australe, Psidium cinereum, Psidium laruotteanum and Psidium rufum were collected , cleaned, crushed and stored in plastic bags until use. In the first stage, were carried out the germination and growth bioassays using aqueous extracts of leaf in a concentration of 10% (w / v). We selected three target species, Lactuca sativa and Solanum lycopersicum, both eudicotyledonous and a monocotyledonous Allium cepa. The extracts were applied to all Myrtaceae species compared with the control (distilled water). In the second phase, bioassays were carried out using aqueous extracts of leaves at concentrations of 5 and 10% (w / v). We selected as target species three weeds Euphorbia heterophylla, Echinochloa crus-galli and Ipomoea grandifolia. The leaf extracts of B. salicifolius, M. multiflora, M. splendens and M. tomentosa were compared to negative control (distilled water) and positive (herbicide Oxyfluorfen). In the third stage were carried out biotests germination, growth, and coleoptile of wheat (Triticum aestivum) to direct chemical extraction of active compounds of M. tomentosa. The extractions were carried out using dried leaves powdered and organic solvents of different polarity, the extracts were fractionated using chromatographic column and purified by HPLC. The isolated and purified compounds were identified in RMN13C and RMN1H, by comparison of spectra. The results showed that aqueous extracts of twelve out of fifteen donor species evaluated showed allelopathic activity and each species showed a distinct behavior regarding the allelopathic activity, no grouping by taxonomic proximity. Evaluating the four species most active on weeds species, was detected the potential and efficiency of the extracts, since these were more toxic to weeds species than the herbicide. The leaf extracts of M. tomentosa stood out for demonstrating high activity even at low concentrations, so was chemical extraction from powdered of leaves of M. tomentosa were isolated two compounds from the ethyl acetate extract: juglanin and avicularin, the difference between ix both is the presence of one hydroxyl attached to carbon 3' in avicularin molecule, this difference has an phytotoxic effect more pronounced in the juglanin. This paper is the first report of the presence of the flavonoids kaempferol (juglanin) and quercetin (avicularin) in species of Myrtaceae of cerrado (Brazilian savanna) and gave foundation for future studies on bioprospecting of the M. tomentosa, which did not find any reports of allelopathic studies, fractionation and identification of chemical compounds. / Os vegetais liberam metabolitos primarios e secundarios no ambiente que podem influenciar no desenvolvimento da vegetacao adjacente, este fenomeno de interferencia e denominado alelopatia. E reconhecida como um processo ecologico importante, pois interfere na estrutura, distribuicao, composicao e dinamica de comunidades vegetais. Estudos sobre interacoes alelopaticas podem ser uteis na busca por fitotoxinas naturais, produzidas por plantas ou microrganismos a serem empregados como herbicidas naturais, mais especificos e menos prejudiciais ao ambiente. De acordo com inventario floristico realizado pelo IBGE a familia Myrtaceae e uma das principais em riqueza e diversidade no ecossistema de cerrado. Assim, este trabalho tentou esclarecer as seguintes questoes: especies da familia Myrtaceae presentes no cerrado apresentam potencial alelopatico? Existe semelhanca na resposta alelopatica dentro dos generos? Dentre as especies ativas, qual a mais promissora para se iniciar uma bioprospeccao? Alguma dessas especies apresenta potencial para utilizacao como herbicida em sistemas agroflorestais ou de producao organica de alimentos? Para responder essas perguntas foram realizados bioensaios de germinacao de diasporos e crescimento de plantulas, de especies alvo cultivadas e infestantes de cultura, e extracao quimica de compostos ativos em folhas de Myrcia tomentosa. As folhas maduras de Blepharocalyx salicifolius, Campomanesia pubescens, Eugenia bimarginata, Eugenia klotzschiana, Eugenia myrcianthes, Eugenia punicifolia, Myrcia bella, Myrcia lingua, Myrcia multiflora, Myrcia splendens, Myrcia tomentosa, Psidium australe, Psidium cinereum, Psidium laruotteanum e Psidium rufum foram coletadas, higienizadas, trituradas e armazenadas em embalagens plasticas ate a utilizacao. Na primeira etapa, os bioensaios de germinacao e crescimento, foram efetuados utilizando-se extratos aquosos de po de folhas em concentracao de 10% (p/v). Como especies receptoras foram selecionadas duas eudicotiledoneas Lactuca sativa e Solanum lycopersicum e, uma monocotiledonea Allium cepa, nas quais foram aplicados os extratos de todas as especies de Myrtaceae comparadas ao controle (agua destilada). Na segunda etapa, os bioensaios foram efetuados utilizando-se extratos aquosos de po de folhas em concentracao de 5 e 10% (p/v). Como especies receptoras foram selecionadas as infestantes de cultura Euphorbia heterophylla, Echinochloa crus-galli e Ipomoea grandifolia, nas quais foram aplicados os extratos de folhas de B. salicifolius, M. multiflora, M. splendens e M. tomentosa, comparadas ao controle negativo (agua destilada) e ao positivo (herbicida Oxifluorfem). Na terceira etapa, foram efetuados biotestes de germinacao, crescimento e de coleoptilo de trigo para direcionar a extracao quimica de compostos ativos de M. tomentosa. Para tanto as extracoes foram feitas empregando-se o po de folhas e os solventes organicos de diferentes polaridades. Os extratos foram fracionados em coluna cromatografica e purificados em CLAE. Os compostos isolados e purificados foram identificados em RMN13C e RMN1H, por comparacao de espectros. Os resultados mostraram que extratos aquosos de doze das quinze especies doadoras avaliadas apresentaram atividade alelopatica e cada especie demonstrou comportamento distinto em relacao a atividade alelopatica, nao houve agrupamento por proximidade taxonomica. Avaliando as quatro especies mais ativas sobre especies invasoras, constatou-se o potencial e a eficiencia dos extratos, uma vez que estes foram mais fitotoxicos as especies invasoras que o herbicida. O extrato foliar de M. tomentosa destacou-se por demonstrar elevada atividade mesmo em baixa concentracao, assim foi realizada a extracao quimica do po folhas desta especie. Foram isolados dois compostos do extrato acetato de etila: juglanina e avicularina, o que as diferencia e a hidroxila ligada ao carbono 3 na molecula de avicularina, esta diferenca produziu efeito fitotoxico mais acentuado da molecula de vii juglanina. O presente trabalho relatou pela primeira vez a presenca dos flavonoides kaempferol (juglanina) e quercetina (avicularina) em uma especie de Myrtaceae do cerrado e deu embasamento para futuros estudos relativos a bioprospeccao da especie Myrcia tomentosa, da qual nao se encontrou nenhum relato de estudos alelopaticos, fracionamento e identificacao de compostos quimicos.
17

Vliv aplikace lignitu na distribuci organického uhlíku v půdě / Influence of the Application of Lignite on the Distribution of Organic Carbon in Soil

Širůček, David January 2019 (has links)
This diploma thesis is focused on optimization of sequential chemical fractionation method to humeomics in order to be useful for determination of organic matter content and distribution and also organic elements in soil. Subsequently, the optimized method is used to assess the efect of lignite application as soil support on these soil characteristics. For these purposes, there were three source matrices of organic matter (lignite, soil and annual soil extraction after lignite application) fractionated by sequential chemical analysis. In parallel, these samples were also fractionated by classic alkaline extraction to obtain the so-called extractable fraction of organic matter (NOM). Individual fractions from sequential chemical fractionation as well as NOM samples were characterized by methods of elemental analysis (determination of organic elements), thermogravimetry (contents of ash, organic matter and moisture) and FTIR spektrometry (structural analysis). The results obtained from a large range of data from all humeomics fractions and NOM fractions showed that the method of sequential chemical fractionation gives higher yields of organic matter compared to classic alkaline extraction. Another indisputable advantage is the fact that the obtained fractions divided according to solubility and strenght of binding to soil inorganics can be better characterized by physical-chemical methods, which provides more detailed information about soil organic matter. The results of the work also show that in order for lignite as a support substance to significantly affect soil properties, a longer time, multiple sampling and repetition of individual fractionations would be needed.
18

Sekvenční frakcionace organické hmoty huminové kyseliny izolované z Leonarditu / Sequential fractionation of organic matter of humic acid isolated from Leonardite

Krist, Tomáš January 2021 (has links)
The aim of the diploma thesis was to optimize the sequential fractionation method of organic matter to be used for physico-chemical characterization of extracted fractions. Humic acid isolated from oxidized brown coal of Leonardite was used as a source matrix of organic matter. An eluotropic series was assembled and sequential fractionation was performed by extraction on a Soxhlet apparatus. The original humic acid and fractions were characterized by elemental analysis (EA) and thermogravimetric analysis (TGA), followed by Fourier transform infrared spectrometry (FTIR), molecular absorption spectrometry (UV/VIS), fluorescence spectrometry and potentiometric titration. Atomic ratios were determined from the results of the elemental analysis. From the measured UV/Vis and fluorescence excitation and emission spectra, the absorption coefficients, resp. fluorescence coefficients. Used fractionation method proved to be a suitable method for studying HA structure. A total of 62 wt. % of initial materiál was extracted, indiivdual fraction amounted from 0.36–30.92 wt. %. From the results of the structural analysis, it is clear that with increasing polarity of the organic solvent, fractions with long aliphatic chains were first isolated and their aromaticity graddualy increased. Non-polar organic solvents were suitable for the extraction of lipid-like coumpounds, while the most polar organic fractions were rich in polar groups and their structual parameters were close to the original humic acid. The fraction extracted with acetonitrile was the most unique fraction. This fraction was rich on nitrogen and amine groups and was similar to protein-like structures. In the last two fractions, extracted with alcohols, a significant bathochromic shift typical of fluorophore type V was observed. Among other things, they were also characterized by a higher content of plant carbohydrate residues.
19

Source Apportionment and Risk Assessment of Urban Diffuse Pollutants of Heavy Metals and Polycyclic Aromatic Hydrocarbons on Urban Watershed

Zhang, Jin 15 March 2019 (has links)
In this Dissertation, systematic work has been carried out to study the road-deposited sediment and its adsorbed pollutants from a stormwater pollution perspective. Solid-phase concentration, surface load, source apportionment, risk assessment, and desorption dynamics of polycyclic aromatic hydrocarbons and/or heavy metals in road-deposited sediments (RDS) were investigated. In order to provide data to assist potential strategies of stormwater pollution mitigation and integrated catchment management to minimise the adverse impacts of RDS adsorbed pollutants on stormwawter quality, the following specific topics were addressed. ⑴ The influences of traffic load and antecedent dry-weather period on pollution level and ecological risk of heavy metals in RDS were analyzed. ⑵ The build-up dynamics and chemical fractionation of metals were determined. ⑶ The potential source contributions and risk assessment of polycyclic aromatic hydrocarbons in size-fractionated RDS were firstly determined by a Principal component analysis - Multiple linear regression receptor model. ⑷ The qualitative and quantitative source apportionments of polycyclic aromatic hydrocarbons were subsequently investigated through a combined qualitative Molecular Diagnostic Ratio and quantitative Positive Matrix Factorization source apportionment with an extended data set. ⑸ The exposure risk of polycyclic aromatic hydrocarbons were evaluated and calculated by incremental lifetime cancer risk models. ⑹ Then, a novel ecological risk assessment approach to the RDS adsorbed toxic substances was developed, which was explored exclusively for the study of RDS for a water pollution aspect. ⑺ Finally, the effects of rainwater, major wastewater constituents of dissolved organic matter and surfactant on the leaching of heavy metals from RDS were carried out.

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