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Avaliação da biodegradabilidade de lixiviado de aterro sanitário consorciado com esgoto doméstico em um sistema biológico de tratamento de efluentesReque, Patrícia Tambosi January 2015 (has links)
O líquido denominado “lixiviado”, formado pela disposição de resíduos em aterros sanitários e lixões, apresenta composição complexa, dada principalmente pela presença de compostos orgânicos extremamente recalcitrantes. O tratamento consorciado deste efluente com esgotos domésticos em ETE’s municipais carece de estudos, tendo em vista que são líquidos com características diferentes. Neste trabalho foi avaliado o desempenho de um processo biológico de tratamento de efluentes, composto por 3 sistemas de banhados construídos (B1, B2 e B3) operados em paralelo, tratando a combinação de esgoto doméstico (90%) + lixiviado de aterro sanitário (10%), no que diz respeito a remoção de matéria orgânica de lenta degradação. Cada sistema foi composto por 4 leitos cultivados com as macrófitas emergentes Luziola peruviana e Typha latifolia, recebendo afluente proveniente de diferentes níveis de pré-tratamento, nomeadamente: B1 - processo biológico anaeróbio (UASB) seguido de aeróbio (CBR); B2 - processo biológico aneróbio (UASB) e B3 - sem prévio tratamento. Para tal, além das análises da matéria orgânica pelos parâmetros não específicos, foi também empregada análise de absorbância e fluorescência para analisar a presença de substâncias húmicas e o uso da respirometria para avaliação da DQO lentamente biodegradável. As eficiências médias de remoção dos sistemas B1, B2 e B3 foi de 97,4, 96,1 e 96,6 % para DBO5, 66,9, 70,9 e 80,6% para DQOT, 61,9, 69 e 62,8 % para DQOFil e de 60,3, 72,8 e 72 % para COT, respectivamente. A avaliação destes parâmetros permitiu inferir que o nível de pré-tratamento não influenciou na eficiência de remoção pelos sistemas de banhados. Os espectros de absorbância foram marcados por maior absorbância na região λ < 400 nm, com diminuição progressiva até 700 nm. A aplicação de coeficientes de absortividade indicaram a predominância de matéria orgânica dissolvida proveniente de esgoto doméstico, com pouca influência de SH’s. Nos espectros de emissão de fluorescência, o aparecimento de bandas na região de 450 nm indicou a presença de substâncias húmicas no afluente e efluente do sistema de banhados construídos, sem diferença significativa entre a intensidade de fluorescência emitida em 450 nm nas amostras analisadas, indicando que a substância em questão passou pelo tratamento sem ser degradada. Os resultados observados pela análise de fluorescência sincronizada do B1 apresentaram contribuição positiva do pré-tratamento (menor concentração de DQOFil) para o desempenho do banhado, devido a menor presença de ácidos húmicos no efluente. / The liquid known as "leachate", produced by the disposal of waste in landfills and dumps, has a complex composition, characterized mainly by the presence of recalcitrant organic compounds. Currently, there is a lack of knowledge regarding the co-treatment of leachate with municipal wastewater in WWTP's, considering that these are effluents with different characteristics. This study evaluated the performance of a biological treatment process of wastewater consisting of 3 constructed wetlands systems (B1, B2 and B3), operated in parallel, treating a combination of domestic sewage (90%) + landfill leachate (10 %). Each system was comprised of four beds cultured with emerging macrophytes Luziola peruviana and Typha latifolia receiving affluent from different levels of pre-treatment, namely: B1 - anaerobic biological process (UASB) followed by aerobic biological process (CBR); B2 - anaerobic biological process (UASB). B3 received the untreated effluents. The content of organic matter and humic substances was analyzed by non-specific parameters, absorbance and fluorescence methods. Respirometry test were conducted to evaluate the content of slowly biodegradable COD. The average removal efficiencies of systems B1, B2 and B3 was of 97.4, 96.1 and 96.6% for BOD5, 66.9, 70.9 and 80.6% for CODT, 61,9, 69 and 62.8% for CODFil and 60.3, 72.8 and 72% of TOC, respectively. The evaluation of these parameters allowed to infer that the level of pre-treatment did not influenced the removal efficiency by wetland systems. Absorbance spectra were marked by greater absorbance in the region λ = <400 nm with progressive decrease up to 700 nm. Absorptivity coefficients indicated the predominance of domestic sewage, with little influence of SH's. In the fluorescence emission spectra, the appearance of bands in the 450 nm region indicated the presence of humic substances in the influent and effluent of the constructed wetland systems without a significant. This indicates that the substance in question went through the treatment without being degraded. The results obtained by synchronous fluorescence analysis showed a positive contribution of the B1 pretreatment (lowest concentration DQOFil) to the observed performance due to less presence of humic acids in the effluent. The authors did not have success during evaluation of the slowly biodegradable COD using the method proposed before.
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Variabilidade espacial da matéia orgânica em um latossolo vermelho-amarelo sob cafeeiro conilonSilva, Leonardo Vidal Monteiro da 17 December 2010 (has links)
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Previous issue date: 2010-12-17 / O objetivo do presente estudo foi avaliar a variabilidade espacial do carbono orgânico total e do carbono orgânico das substâncias húmicas em um Latossolo sob cafeeiro conilon em relevo ondulado, em diferentes épocas de amostragem. O estudo foi realizado em uma área pertencente ao Instituto Capixaba de Pesquisa, Assistência Técnica e Extensão Rural (INCAPER), localizada no distrito de Pacotuba, município de Cachoeiro de Itapemirim, sul do estado do Espírito Santo. O experimento foi instalado em uma área sob um Latossolo Vermelho-Amarelo distrófico, na cultura de café conilon (Coffea canephora). Dentro da região selecionada foram demarcados pontos de amostragens em uma grade irregular, definidos como células, dentro de uma área de aproximadamente 6.000 m2. Cada célula amostral foi composta de cinco plantas de café compondo uma área de 13,05 m2. A malha amostral foi composta de 109 pontos espaçados de forma irregular. A amostragem dos atributos do solo foi realizada em duas épocas distintas de acordo com a pluviosidade. A amostragem referente à primeira coleta de dados foi realizada na primeira quinzena de janeiro de 2009, nas profundidades de 0-10 e 10-20 cm, período este com maior índice pluviométrico. Já a amostragem referente à segunda coleta foi realizada na primeira quinzena de janeiro de 2010, período com baixo índice pluviométrico. Foram determinados o carbono orgânico total, carbono das substâncias húmicas e calculados o estoque de carbono. Realizou-se uma análise aplicando a estatística descritiva, com a comparação das médias pelo teste t-Student. A análise geoestatística foi aplicada para avaliar o grau de dependência espacial dos atributos relacionados à matéria orgânica a partir do ajuste de semivariogramas teóricos aos semivariogramas experimentais. Os mapas de distribuição espacial foram confeccionados através da krigagem ordinária para os atributos que apresentaram dependência espacial. Os resultados apontam diferença significativa entre as épocas de amostragem, com a presença de maiores valores na segunda época de amostragem. O manejo adotado e o tempo entre a primeira e a segunda coleta influenciaram na presença de maiores teores dos atributos relacionados à matéria orgânica na segunda época de amostragem, com exceção do AF e AH na profundidade de 10-20 cm. A análise da variabilidade espacial em conjunto com a krigagem ordinária, possibilitou o mapeamento da variabilidade espacial dos atributos relacionados à matéria orgânica nas duas profundidades e épocas de amostragem, proporcionando melhor visualização do comportamento dos atributos em estudo. A análise da variabilidade espacial mostrou que o relevo e a época de amostragem influenciaram na distribuição espacial das frações das substâncias húmicas / The aim of this study was to evaluate the spatial variability of total organic carbon and organic carbon of humic substances in an Oxisol under conilon coffee in plains, which were planted in different periods of time. The study was conducted in an area which belongs to Espírito Santo State Research, Technical Assistance and Rural Extension (INCAPER), located in Pacotuba, a district of Cachoeiro de Itapemirim, south of Espirito Santo. The experiment was settled in plain areas, under a Red-Yellow Dystrophic Latosol in conilon coffee crop (Coffea canephora). In the region selected soil sampling sites were marked in an irregular grid, defined as cells in an area of about 6,000 m2. The boundary line was accomplished by stacking five plants of the cell sample. The coordinates of each sample point were acquired by a topographic GPS, the GTR-1. Each cell sample was composed by five coffee plants which sets an area of 13.05 m2. The sampling grid of 109 points counted was spaced irregularly. The soil samples properties were performed at two different times according to rainfall. The first data collection was performed in the first half of January 2009, at 0-10 and 10-20 cm, a period with higher rainfall. And the second collection was done in the second half of January 2010, a period with low rainfall. It was possible to determine the total organic carbon, carbon of humic substances and carbon stocks. A qualitative analysis was conducted by applying descriptive statistics, comparing the averages got using the t-Student test. The geostatistical analysis was applied to quantify the degree of spatial dependency of attributes related to organic matter from the adjustment of theoretical functions to experimental semivariograms. The spatial distribution maps were made using ordinary kriging for the attributes that showed spatial dependence. The analysis of attributes related to organic material has observed significant differences between depths for all attributes studied, when the outliers are removed, and the highest levels of attributes were found for the 0-10 cm depth. The results indicate significant differences between sampling times, with the presence of higher values in the second sampling time. The management adopted and the time between the first and second collection influenced the presence of higher levels of the attributes related to organic material in the second sampling time. The geostatistical analysis in conjunction with ordinary kriging, allowed the mapping of the spatial variability of attributes related to organic material at two depths and sampling times, providing better ways to analyze the behavior of the attributes studied. The analysis showed that spatial variability in relief and sampling time influenced the spatial distribution of components of organic matter. The influence of relief on the horizontal movement of the attributes related to organic material was higher for the first sampling time
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Produção e caracterização de nanopartículas de BaTiO3 através da rota sol-gel utilizando substâncias húmicas provenientes da água de rio / Synthesis and characterization of nanoparticles of BaTiO 3 by sol-gel route using humic substances from river waterLima, Camila Higina Santos 24 February 2017 (has links)
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / The goals of the present work consisted in the production of
nanoparticles of pure barium titanate and doped with Nd, by means of an
unpublished route that uses humic substances as complexing agent of the
metalic ions and in the investigation of the influence of the synthesis parameters
on the structural properties, on the crystalization of the material and on the
luminescent properties of doped samples. Barium titanate (BaTiO 3 ) has
potential for application in electro-optical devices, sonars, infrared sensors and
multilayer capacitors. Parameters such as concentration, pH and calcination
temperature were investigated during production, with the purpose of
developing a simple, efficient and low energy cost procedure. The synthesis
route proposed in this work was very promising in the production of BaTiO 3 . The
samples produced with concentration of 0.5 g/ml presented a single tetragonal
phase after calcination at 1200 ºC/5h. The crystallite size was estimated by
Scherrer equation at around 28 nm and the particles were spherical, rod and
needle shaped. The samples of pH 7 and 10 presented a single phase at 1100
ºC/5h and the samples doped with Neodymium presented a single phase at
1200 ºC/5h and a crystallite size estimated at 22 nm. In addition, the
luminescent properties of the doped samples were studied, which were
presented in accordance with the neodymium emission bands in the BaTiO 3
matrix. / Os objetivos deste trabalho consistiram na produção de nanopartículas
de titanato de bário (BaTiO3 ) puros e dopados com Nd
3+
por meio de uma rota
inédita que utiliza as substâncias húmicas como agente complexador dos íons
metálicos e na investigação da influência dos parâmetros de síntese sobre as
propriedades estruturais, na cristalização do material e nas propriedades
luminescentes das amostras dopadas. O titanato de bário (BaTiO 3 ) apresenta
potencial para aplicação em dispositivos eletro-ópticos, sonares, sensores de
infravermelho e capacitores multicamadas. Parâmetros como pH e temperatura
de calcinação foram investigados durante a produção, com o propósito de
desenvolver um procedimento simples, eficiente e de baixo custo para a
produção do titanato de bário. A rota de síntese proposta neste trabalho
mostrou-se bastante promissora na produção do BaTiO 3 . As amostras obtidas
com concentração de 0,5 g/ml apresentaram fase única tetragonal após
calcinação a 1200 ºC/5h. O tamanho de cristalito foi estimado através da
equação de Scherrer em torno de 28 nm e as partículas apresentaram formato
esférico, de bastonetes e de agulhas. Já as amostras de pH 7 e 10
apresentaram fase única a 1100 ºC/5h e as amostras dopadas com Neodímio
apresentaram fase única em 1200 ºC/5h e tamanho de cristalito estimado em
22 nm. Além disso, foi estudada a propriedade luminescente das amostras
dopadas, que se apresentaram em conformidade com as bandas de emissão
do neodímio na matriz do BaTiO 3 relatadas na literatura.
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Conteúdo e qualidade da matéria orgânica em sistemas de uso e manejo do solo no Bioma Pampa. / Content and quality of organic matter under use systems and soil management on the Pampa BiomeFarias, Marla de Oliveira 13 October 2010 (has links)
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Previous issue date: 2010-10-13 / Conservation tillage systems contribute to maintaining or increasing soil organic
matter (MOS). In Pampa Biome studies that evaluate the dynamics of MOS in
agroecossystems under different land use systems and soil management were
scarce. The aim of this work was to evaluate the effect of different use systems and
soil management on the content and quality of MOS in two different soils of
southern of RS. Soil samples from a Albaqualf were collected in Embrapa Clima
Temperado, Capão do Leão (RS) in a field experiment with four years, the layer
from 0,000 to 0,025 m, in the following treatments: PD no tillage and PC
conventional tillage [growihg with ryegrass + birdsfoot (winter) and
soybean/corn/sorghum crop rotation (summer)] and CN native pasture. In the
entire and the macroagregates samples were chemical fractionated and the content
and stocks of total organic carbon (COT), total nitrogen (NT) and the contents and
stocks of carbon (C) in the humic fractions (fulvic acid AF; humic acid AH and
humin HU) were quantified. The chemical and molecular characteristics of HA
extracted were determined by elemental composition (CHNO) spectroscopy, FTIR,
EPR and UV-fluorescence visible. The agricultural use resulted in a decrease in
COT and C humic fractions in the entire soil and macroaggregates. In the
macroaggregates were found the largest proportions of HU fraction. There was a
relative enrichment of C of AH form. The elemental composition revealed that AH
was rich in N and with high resistance to decomposition and that the
macroaggregates under PC in AH showed a higher degree of humification. The
FTIR analysis showed that the functional groups of AH are similar among different
use systems and management. The analysis of EPR and fluorescence indicates a
higher degree of decomposition of organic compounds in soil under PC reflecting a
higher degree humification of AH, compared to PD. In another place, soil samples
were collected from a Paleaudalf in Estância Sá Brito, Alegrete (RS), in an
experiment with five years, in the layers from 0.000 to 0.025 m, 0.025 to 0.075
0.075 to 0.125 m depth. The treatments were: FH homogeneous forests of
Eucalyptus grandis; SA silvopastoral system consisting of eucalyptus and
pasture; CN pasture native. The entire soil samples were subjected to chemical
fractionation and quantified the levels and values of COT and NT contents and C
stocks in the humic fractions in AF, AH and HU. The FH system presented potential
to promote recovery of MOS in areas with process of the arenization. The most part
of the MOS is stored in the humic form substances, especially in the form HU
reflecting the importance of the interaction of MOS with the mineral matrix to its
preservation and stabilization. / Sistemas conservacionistas de manejo contribuem para a manutenção ou
incremento da matéria orgânica do solo (MOS). No Bioma Pampa, escassos são os
estudos que avaliam a dinâmica da MOS em agroecossistemas sob diferentes
sistemas de uso e manejos do solo. O objetivo deste trabalho foi avaliar o efeito de
sistemas de uso e manejo do solo sobre o conteúdo e qualidade da MOS de dois
solos da metade sul do RS. Amostras de solo de um Planossolo Háplico foram
coletadas a campo na Estação Experimental Terras Baixas da Embrapa Clima
Temperado, Capão do Leão (RS), em um experimento de campo instalado há quatro
anos, na camada de 0,000 a 0,025 m, nos tratamentos: PD plantio direto e PC
plantio convencional [cultivados com azevém + cornichão (inverno), e rotação
soja/milho/sorgo (verão)] e CN campo nativo. As amostras de solo inteiro e de
macroagregados foram submetidas ao fracionamento químico e quantificados os teores
e estoques de carbono orgânico total (COT) e nitrogênio total (NT) e teores e estoques
de carbono (C) nas frações húmicas (ácido fúlvico AF, ácido húmico AH e humina
HU). As características químicas e moleculares do AH extraído foram determinadas
por composição elementar (CHNO), espectroscopia de FTIR, EPR e fluorescência
de luz UV-Visível. O uso agrícola anterior à instalação da área experimental,
provocou redução no COT e C das frações húmicas, no solo inteiro e nos
macroagregados. Nos macroagregados foram encontradas as maiores proporções
da fração HU. Houve um enriquecimento relativo de C na forma de AH. A
composição elementar revelou AH ricos em N e com alta resistência à
decomposição, sendo que nos macroagregados sob PC os AH apresentaram maior
grau de humificação. A análise de FTIR mostrou que os grupos funcionais dos AH
são semelhantes entre os diferentes sistemas de uso e manejo, porém as análises
de EPR e fluorescência indicaram maior grau de decomposição dos compostos
orgânicos no solo sob PC, refletindo-se num maior grau de humificação dos AH, em
comparação ao PD. Em outro ambiente, amostras de um Argissolo Vermelho foram
coletadas na Estância Sá Brito, Alegrete (RS), em um experimento instalado há
cinco anos, nas camadas de 0,000 a 0,025 m, 0,025 a 0,075 m e 0,075 a 0,125 m,
nos tratamentos: FH florestamento homogêneo de Eucalyptus grandis; SA
sistema silvipastoril constituído de eucalipto e pastagem; CN campo nativo. As
amostras de solo inteiro foram submetidas ao fracionamento químico e quantificados
os teores e estoques de COT e NT e teores e estoques de C nas frações húmicas
AF, AH e HU. O sistema FH apresentou potencial para promover a recuperação da
MOS em áreas sob processo de arenização. A maior parte da MOS encontra-se
armazenada na forma de substâncias húmicas, em especial na forma de HU,
refletindo a importância da interação da MOS com a matriz mineral para a sua
preservação e estabilização.
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A study of the kinetic interactions of complex metal ion : humic and magnetite ternary systemsLi, Nigel January 2012 (has links)
The sorption of humic acid (HA) and HA size fractions onto magnetite has been studied. There is considerable irreversibility in the interaction of the humic with the magnetite surface, but the presence of Eu3+ ions has no effect on the sorption of humic onto magnetite. The magnitude of the sorption to magnetite increases with HA fraction size for all ionic strengths between 0.01 and 3 mol dm-3. Increasing ionic strength also increases sorption. Asymmetric Flow Field Flow Fractionation analysis of HA sorption to magnetite after 1 day revealed preferential sorption of lower molecular weight material. Eu3+ sorption onto magnetite was studied as a function of Eu concentration, which showed an increase in relative sorption as Eu concentration decreased. The behaviour of Eu3+ in ternary (HA/Eu3+/magnetite) systems is heavily influenced by HA, and from the data there is direct evidence for ternary complex formation. Larger HA size fractions retain more Eu3+ in solution than the smaller fractions. The binding strengths of HA size fractions were determined through ion exchange resin experiments: generally the larger fractions (> 10 kDa) showed stronger binding than the smaller components, but the unfractionated sample showed the strongest binding.First order dissociation rate constants have been determined for the whole HA and HA size fractions. The dissociation rate constants are independent of HA fraction size, but the larger species bind more Eu non-exchangeably. Time series ultrafiltration of Eu3+/whole humic mixtures has shown a shift in the distribution of metal ions to larger size fractions after a few days. Two ternary system kinetic speciation models have been developed to predict the behaviour of HA and Eu3+ in ternary systems. The two differ in their description of the multi-component behaviour of the binary HA-mineral interaction. The first assumes a single HA species and two surface binding sites and was found to perform better overall than the second, which has a single surface sorption site and two HA species in solution. The exchangeable binding strengths for the different HA samples calculated from both models showed similarities to those measured experimentally.
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Interakce ibuprofenu s huminovými látkami a stabilita vzniklých komplexů / Interaction of Ibuprofen with Humic Substances and Stability of Formed ComplexesVlašicová, Silvie January 2021 (has links)
Nowadays, huge amounts of drugs get into watercourses and soil due to wrong disposal in sewage treatment plants. In this work, the sorption and desorption behavior of Ibuprofen in the soil system was studied, especially in relation to humic acids. The degree of sorption and desorption was defined from the change in ibuprofen concentration analyzed by UV-VIS spectrometry, changes in conductivity and pH were also observed. Ibuprofen shows good sorption properties, desorption was really minimal. It can be assumed that there is a strong bond between ibuprofen and both soil and lignite humic acids and therefore there is no risk of leaching back into solutions. Therefore, if ibuprofen entered the environment, it would be sorbed into the humic acids contained in lignite or soil, which means that it should not be harmful in any way.
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Studium transportu kapalných lignohumátů přes listy rostlin a rostlinné kutikuly / Study on transport of liquid lignohumates through plant leaves and plant cuticlesRampáčková, Eliška January 2019 (has links)
This thesis deals with the study of transport commercial solution of pottasium lignohumate through the plant cuticles, as the main barriers in transport of active ingredience to plant tissues. The problematics has been studied to obtain the informations about ability of transport liquid active ingredience during foliar fertilization, which became popular in theme of efective utilization fertilizers and reduction their negative impact to enviroment. The aim of this thesis was to optimize technics of diffusion for demanded purposes in the Stokes diffusion cells. As the transport barriers have been used the plant cuticles, that have been isolated by various methods. The ultraviolet and visible spectrometry (UV-VIS) was the analytical method for determination of transported volume of lignohumate and to the mentioned experiments the cuticles of Prunus laurocerasus and cuticles of tomato fruit have been used. The isolated cuticles have been analyzed by optical microscopy, scanning electron microscopy and profilometry. The characterisation of the used solution of lignohumate was also important part of this thesis. It has been used the basic physico-chemical methods and also the advanced methods as tensiometry, size exclusion chromatography with UV detector and differential refractive index detector (SEC-UV-dRI) and thermogravimetry (TGA).
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Hydratace biokolidů - kalorimetrická studie / Hydration of biocolloids - calorimetric studyŠméralová, Ester January 2019 (has links)
Presented master's thesis focuses on the study of hydration of selected biocolloid substances, specifically humic substances (humic acids and fulvic acids), hyaluronic acid with three different molecular weight, chitosan and dextran. Interaction of biocolloids with water was studied by different methods. The effect of solubility, structure, functional groups in molecule on sorption and hydration ability of these biocolloids was investigated. In the case of hyaluronan the influence of molecular weight was also study. Differential scanning calorimetry DSC and perfusion calorimetry give results of heat of hydration, enthalpies and temperature of crystallization and melting. Thermogravimetric analysis TGA was used to determine the original moisture content of the samples.
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Produkce a charakterizace regenerovaných huminových kyselin / Production and characterization of regenerated humic acidsUhrová, Anna January 2008 (has links)
Jihomoravský lignit pocházející z dolu Mír v Mikulčicích, Lignit s.r.o. byl přesítován a vybraná frakce byla modifikována tzv. mokrou cestou pomocí dvou oxidačních (HNO3, H2O2) a dvou „amfifilních“ (kyselina octová, kyselina citronová) činidel. Alkalickou extrakcí byly získány jak huminové kyseliny z neupraveného tak předupraveného lignitu (tzv. regenerované huminové kyseliny). Na základě výsledku elementární analýzy byly vypočítány C/O a C/H poměry, které společně s FTIR spektry podaly informaci o stupni alifaticity/aromaticity a dále o stupni oxidace organického uhlíku. Pomocí vysokoúčinné vylučovací chromatografie byla stanovena distribuce velikosti huminových agregátů. K objasnění procesů probíhajících v povrchové vrstvě bylo proměřeno povrchové napětí studovaných roztoků vzorků. Získaná data byla proložena Szyszkowského rovnicí a obdržené parametry poukázaly jak na povrchovou aktivitu jednotlivých huminových kyselin tak i na povahu molekul zodpovědných za snižování povrchového napětí. Pro vzájemnou korelaci dat získaných výše zmíněnými metodami byl použit Pearsonův korelační koeficient.
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Agregační reakce chitosanu využitelné při úpravě pitné vody. / Aggregation reactions of chitosan in drinking water treatmentLeskovjanová, Jana January 2008 (has links)
The diploma thesis deals with treatment of surface waters containing humic substances. The most often used method of surface water treatment is coagulation with subsequent separation of aggregates. In this study, only perikinetic coagulation phase was studied. It is the phase when aggregates are formed by the Brownian motion only, i.e. without mixing. Separation of the formed aggregates was made by centrifugation. Coagulation tests were made under the laboratory conditions with model humic water. Humic substances were added from a concentrate, which was taken from a natural peatbog. The influence of temperature on the coagulation process was studied, ranging from 5 to 22 °C. Chitosan (natural biopolymer) was used as coagulant. In present, it is not used in Czech water treatment practice yet. No effect of temperature was observed when chitosan was used as coagulant. Influence of temperature was also studied with the use of aluminium and ferrous sulphates, which are used in common praxis as coagulation reagents. Influence of the temperature was observed and is in agreement with previously reported data of pilot-plant experiments by other researchers. Spectroscopic methods were used to evaluate the coagulation efficiency and determine residual concentration of aluminium and ferrous coagulant. Chemical oxygen demand (COD) was determined for optimal doses. At first, coagulation tests were made under the laboratory temperature. This tests determined optimal aggregation time and optimal coagulant dose under low temperature. Afterwards, all coagulants used were compared at given temperatures.
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