Dissertations / Theses: 'Soils Cations'

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Thomas, Jacob. "A study of factors controlling pH in Arctic tundra soils." Thesis, Umeå universitet, Institutionen för ekologi, miljö och geovetenskap, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-163364.

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In Arctic tundra soils pH serves as an important parameter related to several biotic parameters such as, plant and microbial community composition, biodiversity, nutrient dynamics and productivity. Both abiotic and biotic factors, for instance, base saturation (BS) and plant nutrient uptake may exert a control on soil pH, while it is still unclear to what extent different factors can explain soil pH across different tundra vegetation types. The aim of this study was to investigate to what extent different abiotic and biotic factors influence soil pH in the humus layer across different tundra vegetation types. To do so, eight different tundra vegetation types of which four were underlaid by permafrost (Arctic Alaska) and four with no permafrost (Arctic Sweden) were studied in detail with regard to different properties affecting soil pH. I found that BS was the main factor controlling soil pH across the different vegetation types regardless if the soil was underlain by permafrost or not. Factors, such as, ionic strength or soil water content could not explain any overall pH variation and did only significantly affect the heath soils. Further, the uptake of the most abundant base cations (Ca2+, Mg2+ and K+) from meadow and heath vegetation revealed a high difference between plant functional groups within the same vegetation types. The higher dominance of slow growing woody species in heath vegetation which had a lower uptake corresponded with a lower BC content (especially (Ca2+), pH and BS in the humus soil relative the meadow meanwhile the content of K+ was more than three times higher in heath. Overall, this study suggests that the degree of neutralization (base saturation) regulates pH either via the influence of bedrock and hydrogeochemistry and/or via plant traits that affects the uptake and turnover of base cations.

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Olofsson, Jonas. "Base cations in forest soils : A pilot project to evaluate different extraction methods." Thesis, Institutionen för mark och miljö, Sveriges lantbruksuniversitet, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-308442.

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The acidification has been a known problem in Sweden for several decades. Sulphurous compounds, spread from the British Isles and the European continent led to a decrease in the pH-value of the rain that fell over Sweden. Since the acidification was discovered in the 1960s, active measures against the sulphurous deposition have been undertaken. The sulphurous deposition has decreased by 90 %, and the problem was for some time considered under control, until recently when a new era of the acidification may have started. Due to the increased demand of renewable energy, and Sweden’s potential to use biomass instead of fossil fuels, whole tree harvesting has been more utilized. Studies indicate that the forest soils are depleted in base cations in a faster rate when whole tree harvesting is performed compared to regular stem harvesting. Mass balance calculations and simulations indicate that an increased bio uptake of base cations due to whole tree harvesting leads to an increased biological acidification. However, although many studies agree that the impact of the whole tree harvest on the base cation supply of the soils is significant, long running Swedish experiments indicate that the difference between whole tree harvesting and regular stem harvesting diminishes over time. After a 40 year period, the difference in base cation supply between whole tree harvested soils and stem harvested soils are small. The reason for this could be different processes that reallocate base cations from different pools, which are not usually studied. The aim has been to investigate and evaluate different chemical extraction methods (Aqua Regia, HCl, EDTA, BaCl2, NH4OAc and water) capability to extract the base cations calcium, potassium, magnesium and sodium from four different Swedish forest soils and what this means for our understanding of how much base cations a soil contains. The extractions indicated that there is a statistical significant difference between the methods ability to extract base cations. Generally Aqua Regia was the most potent method, followed by HCl, EDTA, BaCl2, NH4OAc and water in decreasing order of effectiveness to extract the base cations. Linear correlations were found between EDTA, BaCl2 and NH4OAc. The internationally widely used method NH4OAc was considered to be at risk of underestimating the amount of base cations in the soil.
Försurningsproblematiken har länge varit ett känt problem i Sverige. Svavelhaltiga föroreningar som spreds från de brittiska öarna och den europeiska kontinenten ledde till att pH-värdet i regnet som föll över Sverige sjönk. Sedan upptäckten på 60-talet har aktiva åtgärder vidtagits mot utsläppen vilket har lett till en minskning av de försurande föroreningarna med 90 %. På grund av den stora utsläppsreduktionen som skett ansågs försurningsproblematiken vara under kontroll, tills nyligen då en ny etapp av för- surningen kan ha påbörjats. På grund av den ökande efterfrågan av förnyelsebar energi, i kombination med Sveriges stora skogstillgångar, har helträdsskörd av träd blivit alltmer nyttjad. Studier visar att markens baskatjonförråd utarmas i större utsträckning av helträdsskörd, då även grenar, rötter och toppar tas om hand jämfört med vanlig stamskörd då endast stammen tas med från skogen. Massbalanssimuleringar antyder att ett ökat bioupptag av baskatjoner på grund av helträdsskörd leder till en ökad biologisk försurning. Trots att många studier är överens om helträdsskördens inverkan på markens innehåll av baskatjoner visar lång- liggande försök i Sverige att skillnaderna mellan uttag av hela träd och stamved minskar med tiden. Efter en period på 40 år återstår endast små skillnader mellan avverknings- metoderna. Orsakerna till varför mätningarna och massbalansberäkningarna och simuleringarna inte stämmer överens kan vara många, t.ex. att det finns processer som kan omfördela baskatjoner från de som vanligtvis studeras. Syftet har varit att undersöka och utvärdera olika kemiska extraktionsmetoders (Aqua Regia, HCl, EDTA, BaCl2, NH4OAc och vatten) förmåga att extrahera baskatjonerna kalcium, kalium, magnesium och natrium från fyra olika skogsjordar i Sverige och vad resultaten betyder för vår uppfattning av mängden baskatjoner i marken. Extraktionerna visade att en statistiskt signifikant skillnad fanns mellan metodernas förmåga att extrahera de olika baskatjonerna. Generellt var Aqua Regia den metod som extraherade den största mängden baskatjoner, HCl, EDTA, BaCl2, NH4OAc och vatten följde i fallande ordning efter förmåga att extrahera baskatjonerna. Linjära korrelationer mellan EDTA, BaCl2 och NH4OAc upptäcktes. Den internationellt ofta använda metodiken för att extrahera baskatjoner, NH4OAc, ansågs riskera att underskatta mängden baskatjoner i marken.

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Giffen, Cynthia Jean. "Comparison of base cations in streams and soils in two small western Maryland watersheds." College Park, Md. : University of Maryland, 2005. http://hdl.handle.net/1903/2665.

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Thesis (M.S.) -- University of Maryland, College Park, 2005.
Thesis research directed by: Marine-Estuarine-Environmental Sciences. Title from t.p. of PDF. Includes bibliographical references. Published by UMI Dissertation Services, Ann Arbor, Mich. Also available in paper.

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Mannings, Stephen. "The influence of acid deposition on the mobility of base cations and heavy metals in soils." Thesis, King's College London (University of London), 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.360204.

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Bate, Bate. "Engineering behavior of fine-grained soils modified with a controlled organic phase." Diss., Georgia Institute of Technology, 2010. http://hdl.handle.net/1853/39627.

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Organic materials are ubiquitous in the geologic environment, and can exert significant influence over the interfacial properties of minerals. However, due to the complexity in their structure and interaction with soil solids, their impact has remained relatively unquantified. This study investigated the engineering behaviors of organoclays, which were synthesized in the laboratory using naturally occurring clay minerals and quaternary ammonium compounds of controlled structure and density of loading. Organic cations were chosen to study the effects of functional group structure and size. The laboratory investigation showed that the presence of the organic cations on the mineral surfaces led to increased hydrophobicity of all clays tested. Conduction studies on the electrical, hydraulic, and thermal properties of the organoclay composites suggested that increasing the total organic carbon content resulted in decreased electrical and thermal conductivity, but increased hydraulic conductivity, due to the reduced swelling of the base clay mineral phase. Electrokinetic properties of the organoclays illustrated that compared with the clay's naturally occurring inorganic cations, exchanged quaternary ammonium cations were more likely bound within a particle's shear plane. Consequently, organoclays had less negative zeta potential than that of unmodified bentonite. Increasing the length of one carbon tail was more effective at binding organic cations within the shear plane than increasing the size of the cation, when compared on the basis of total organic carbon content. In terms of large strain strength, the modified organic clays exhibited increased shear strength, in part owing to the reduction in water content caused by the presence of the hydrophobic organic layering. Shear strength increased with single carbon tail length or with cation size, although the latter effect tended to reach a plateau as the length of the four short cation tails increased from 2 to 4. In terms of small strain behavior, the shear modulus was shown to be a function of the total organic carbon content. It is believed that number of particle contacts increased as the organic carbon content increased. Stiffness increased as either the size of the cation or the total organic carbon content was increased. Damping also increased as the organic loading was increased, with the organic phase acting as an energy dissipation mechanism.

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Uprety, Rajendra Prasad. "Perspectives on soil cation exchange capacity : analysis, interpretation and application." Thesis, University of Aberdeen, 2016. http://digitool.abdn.ac.uk:80/webclient/DeliveryManager?pid=231062.

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At the heart of long term sustainable soil management is chemical fertility through the retention of exchangeable cations. Many current concepts of cation exchange and its relationship with base cation availability remain unchanged over the past century. Despite considerable advancements in analytical techniques many methods used today would be familiar to our forefathers. Comparative studies were undertaken in this thesis to understand how techniques to measure exchangeable soil ions could be enhanced and matched to defined scenarios. The total amount of cations that can be retained electrostatically on soil surfaces is termed the cation exchange capacity (CEC). An ability to systematically and consistently measure CEC is an essential step in soil characterisation. Compulsive exchange methods (using either 1.0 M NH4OAc or 0.05 M BaCl2) at a fixed pH value for determining CEC were scrutinised but acknowledged to be prone to systematic artefacts. The relationship between soil pH, soil texture and CEC was soil specific. When the batch method was compared with the column leach method, the former was more consistent for all soils. For calcareous soils BaCl2 was more suitable but NH4OAc was more generally applicable. The CEC was consistently significantly greater by the compulsive technique when compared with the effective method. The NH4OAc extraction method was applied to soils contaminated with potentially toxic elements (PTEs). The exchangeable concentration of PTEs correlated with total PTE loading. However, the exchangeable Ca decreased with amendment rate confirming an exchange of sites by PTEs. The compulsive technique extracted PTEs that were significantly 2 negatively correlated with soil basal respiration, phosphatase activity, potential nitrification rate (PNR) and the soil microbial biomass carbon. This confirms that of this method is evaluating the bioavailable/bioreactive fraction. Soil cation exchange capacity and exchangeable base cations increased commensurate with the amendment loading of bentonite and charcoal. The exchange capacity was also soil specific. Following amendments, the exchange capacity was higher after six weeks than after thirty weeks. This means that the amendment performance became impaired with time perhaps as the fine soil particles coated the ameliorant causing a decline in CEC. The difference between the effective and compulsive CEC was described as the calculated CEC. This was very sensitive to soil pH and was confirmed in a detailed study at a site where pH plots were amended over a five decade period. As pH rose, so did the exchangeable fraction of Ca, Mg and K. As the pH declined, Al, Fe and Mn exchangeability increased. Extraction techniques must be sympathetic of the soil pH value. The quantification and characterisation of exchangeable cations remains as fundamental a component of soil science today as it was a century ago.

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Arthur, Jennifer D., Noah W. Mark, Susan Taylor, J. Šimunek, M. L. Brusseau, and Katerina M. Dontsova. "Batch soil adsorption and column transport studies of 2,4-dinitroanisole (DNAN) in soils." ELSEVIER SCIENCE BV, 2017. http://hdl.handle.net/10150/624067.

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The explosive 2,4,6-trinitrotoluene (TNT) is currently a main ingredient in munitions; however the compound has failed to meet the new sensitivity requirements. The replacement compound being tested is 2,4-dinitroanisole (DNAN). DNAN is less sensitive to shock, high temperatures, and has good detonation characteristics. However, DNAN is more soluble than TNT, which can influence transport and fate behavior and thus bio-availability and human exposure potential. The objective of this study was to investigate the environmental fate and transport of DNAN in soil, with specific focus on sorption processes. Batch and column experiments were conducted using soils collected from military installations located across the United States. The soils were characterized for pH, electrical conductivity, specific surface area, cation exchange capacity, and organic carbon content. In the batch rate studies, change in DNAN concentration with time was evaluated using the first order equation, while adsorption isotherms were fitted using linear and Freundlich equations. Solution mass-loss rate coefficients ranged between 0.0002 h(-1) and 0.0068 h(-1). DNAN was strongly adsorbed by soils with linear adsorption coefficients ranging between 0.6 and 6.3 L g(-1), and Freundlich coefficients between 1.3 and 34 mg(1-n) L-n kg(-1). Both linear and Freundlich adsorption coefficients were positively correlated with the amount of organic carbon and cation exchange capacity of the soil, indicating that similar to TNT, organic matter and clay minerals may influence adsorption of DNAN. The results of the miscible-displacement column experiments confirmed the impact of sorption on retardation of DNAN during transport. It was also shown that under flow conditions DNAN transforms readily with formation of amino transformation products, 2-ANAN and 4-ANAN. The magnitudes of retardation and transformation observed in this study result in significant attenuation potential for DNAN, which would be anticipated to contribute to a reduced risk for contamination of ground water from soil residues.

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Keskin, Sheena Margaret. "Photosynthetic adaptations in grasses to abnormal levels of soil cations." Thesis, University of Central Lancashire, 1985. http://clok.uclan.ac.uk/20893/.

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This research investigated adaptation of photosynthesis manifest in populations of grasses adapted to growth on abnormal levels of cations. The main investigative plants belong to the Agrostis genus. Plants were sampled from habitats with soi.ls which provided a range of abnormal levels of cations; mine spoil sites with heavy metal contaminations, calcareous and acidic sites with contrasting levels of cations particularly calcium and serpentine sites with low calcium and high magnesium and nickel levels were sampled. Barley and lettuce were used as comparative material as they are more routinely used in photosynthesis investigations. A commercially available seed stock of a heavy metal tolerant cultivar of Festuca rubra was compared with a non—tolerant cultivar. The comparative responses of plants to metals were examined using a range of monitors of photosynthetic reactions including fluorescence, oxygen evolution and light—induced electron transport. Techniques involving the measurement of steady state emission fluorescence spectra of excised leaves were standardised and applied. The soil conditiens were shovn to have a marked effect on the flucrescence spectra of leaves of barley plants grown in a rccge of soil typcs. The assay of light—induced oxygen evolution from excised leaf segments of the Merlin cultivar of Festuca clearly showed that increased resistance to metal inhibition is also present in the leaves as well as in the roots. The increased tolerance could be due to modifications of the cell wall or cytoplasm as has been extensively studied in the root. However a greater relative metal tolerance was also demonstrated in this cultivar at the level of the chioroplast membranes. Isolated, broken (type D) chloroplasts from ten Agrostis ecotypes showed a variation in their sensitivities to metals in the light—induced photosynthetic electron transport through photosystem 2. The chloroplasts from the mine spoil Agrostis races were more resistant to inhibition by the heavy metals (Pb, Zn, Cu, Ni, Cd) in general, although the degree of tolerance did not always relate directly to the root toiernr.ce indices or exchangeable soil metal content. A co—sensitivity between calcium and cadmium was revealed in the roots and in the chloroplasts which is probably related to the similarity in the two cations ionic radii. Plants from high calcium soils showed an increased tolerance to cadmium. The results recorded from work on chlorcplasts isolated from lettuce, barley and Agrostis ecotypes showed that Ca" can have fundamental effects on photosynthesis, both stimulatory and inhibitory. Ca 2+ was shown to stimulate the light—induced photosynthetic electron transport rates through PS2 and to protect isolated chloroplasts from loss of acti'Qity with ageing. Hcwever the degree and nature of the Ca2+ effect was dependent on plant species, ecotype, growing conditions and experimental protocol of CaZ+ addition. 'A marked inhibition with incubation in Ca' 4 after IL extraction was measured in four Agrostis races which originated from soils with low exchangeable calcium levels. However not all low soil_CaZ+ Azrostis ecot ypes were inhibited and this was interpreted to indicate a division between distributional calciftges and physiological calciophcbes. SE! PAGE profiles of chloroplasts from within Agrostis and Festuca were compared for differences in the band regions reported in the literature to be associated with metal tolerance and Ca2+ binding in other species. Variations in the levels of proteins in the 30 and 36 kDa ranges have been obsened in the Pb— and Znresistant Festuca. In the Agrostis, Ca 2 /Cd'' sensitivity in three races is co—incidental with reduction in a band La the region of 30-33 kDa. A loss or gain of a specific band could not be associated with heavy metal tolerance in the Agrostis chloroplasts. It is therefore clear from this work that photosynthetic activity of isolated chloroplasts depends on (a) the heavy metalard Ca2+ content of the soils at the collection site (b) the Ca2+ level of the growth medium (c) the level of Ca 2 in the extraction buffer. The variable ebloroplast activity is probably a reflection of genetic adaptations of the plants to variable growth conditions. This is reflected in variations in proteins in the chloroplasts.

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Abbas, Farhat. "The effect of surface-solute interactions on the transport of solutes through porous media." Thesis, University of Newcastle Upon Tyne, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.324867.

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Pateras, Dimitrios Thomas. "Diffusion, cation exchange and hydrolysis during the reclamation of saline, clay soils." Thesis, University of Reading, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.278092.

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Lu, Jun. "Développement de modèles prédictifs décrivant le couplage chimie-transport dans les sédiments naturels." Thesis, Poitiers, 2013. http://www.theses.fr/2013POIT2287/document.

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La gestion de sols ou sédiments contaminés par des métaux nécessite de pouvoir prédire la migration de ces métaux, dont la mobilité dépend des propriétés de transport du milieu ainsi que de la réactivité chimique de celui-ci (principalement réactions sorption/désorption). Pour étudier l'adsorption des cations métalliques (majeurs et traces) en condition dynamique, des expériences de transport en colonne ont été réalisées avec un sol pauvre en minéraux carbonatés et en matière organique. Considérant que la réactivité de ce sol était due essentiellement à la phase argileuse smectitique, un modèle d'adsorption basé sur les propriétés de rétention de la montmorillonite du Wyoming, utilisant la théorie des échangeurs d'ions multi-sites a été intégré à un code de transport 1D. Les prédictions calculées par ce modèle ont ensuite été comparées aux courbes de percées mesurées dans cette étude et reportées de la littérature. L'étude sur le transport réactif des cations majeurs a mis en évidence le rôle significatif des protons (et ce même à des pH proche de la neutralité), et a permis de valider le modèle pour le transport compétitif des cations majeurs (Na et Ca). Cependant, l'étude de la rétention de Zn(II) a mis en évidence une incohérence entre les résultats issus des expériences batch et ceux obtenus avec les expériences colonne, que l'on pourrait attribuer à la contribution d'une autre phase adsorbante (illite). Néanmoins, le modèle d'adsorption proposé a permis de reproduire avec une bonne satisfaction des données expérimentales de rétention de Zn(II) proposées dans la littérature et obtenues avec des expériences colonne
Management of soils or sediments contaminated by metals requires to predict the migration of metallic cations, whose mobility depends both on the transport properties of the medium and chemical reactivity of the system (principally sorption/desorption reactions). To study the sorption of metallic cations (major and trace) in dynamic condition, transport experiments using columns have been carried out with a soil poor in carbonated minerals and organic matter. Considering that the reactivity of this soil was mainly due to swelling clay minerals, a sorption model based on the sorption properties of the Wyoming montmorillonite and built according to a multi-site ion exchanger theory has been integrated into a 1D transport code. The predictions given by this model were then compared with the breakthrough curves measured in this study and those reported in the literature. The study of the reactive transport of major cations highlighted the significant role of protons (even at near neutral pH), and validated the model for major cations (Na and Ca). However, the study concerning Zn (II) showed a discrepancy between the results obtained from batch experiments and those issued from column experiments, which could be attributed to the contribution of another sorbent phase (illite). Finally, the proposed sorption model allowed reproducing with a good confidence experimental data reported from literature for sorption of Zn (II) in dynamic conditions

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Souli, Hanène. "Études hydromécanique et physico-chimique de deux argiles en présence de cations métalliques." Châtenay-Malabry, Ecole centrale de Paris, 2006. http://www.theses.fr/2006ECAP1011.

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Les argiles présentent des propriétés d'imperméabilité et de rétention intéressantes, qui favoisent leur utilisation dans de nombreux domaines, en particulier dans les systèmes d'étanchéité des centres d'enfouissement de déchets. Les travaux présentés dans cette thèse se situent dans ce cadre, à l'interface entre l'hydromécanique et la physico-chimie. Dans la première partie, l'objectif est d'étudier les prorpiétés hydromécaniques de deux argiles prises dasn différents états initiaux, dans une large gamme de contraintes mécaniques et hydriques. Les essais mettent en évidence les modifications des propriétés hydromécaniques (pression de gonflement, compressibilité, propriétés capillaires. . . . . ) des deux argiles en contact avec l'eau en fonction de leur minéralogie et des états initiaux de compactage. Ces modifications ont aussi été mises en évidence par des méthodes qui permettent des interprétations à des échelles pluspetites comme la diffraction des rayons X, la porosimétrie au mercure, la BET et les mesures de surface spécifique. Le but est d'établir un lien entre les comportements macroscopiques et microscopiques à travers les modifications de texture et de structure des matériaux. La deuxième partie, consiste en une étude de l'influence des cations métaaliques sur les propriétés de gonflement et sur l'organisation des deux argiles. Les cations métalliques étudiés sont le plomb, le zinc et le chrome. Pour étudier les propriétés de gonflement, les échantillons ont été soumis à des humidifications sous charge constante en utilisant deux concentrations de la solution de saturation afin de simuler le comportement de la barrière dans des états différents. La cinétique de gonflement des échantillons en présence des trois cations a aussi été mesurée, ainsi que leur compressibilité et leur comportement sur chemin d'humidification. Les résultats on été comparés à ceux obtenus dans le cas de l'eau. La diffraction des rayons X, la porosimétris au mercure, les mesures de BET ont permis d'avoir des informations sur l'organisation des échantillons, leur porosité, les interactions avec les cations métalliques. Enfin, la dernière partie est cinsacrée à la mesure de la perméabilité des deux argiles et à l'étude de l'influence des cations métalliques et de leur concentration sur ce paramètre. Les mesures sont réalisées en régime permanent et en régime transitoire et complétées par des mesures d'indices des vides et de porosimétris au mercure afin d'interpréter les résultats.

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Lusk, Mary Gilchrist. "Sulfate Dynamics and Base Cation Release in a High Elevation Appalachian Forest Soil." Thesis, Virginia Tech, 1998. http://hdl.handle.net/10919/36692.

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Two soils from the Fernow Experimental Forest near Parsons, West Virginia were characterized and evaluated in terms of their susceptibility to enhanced soil acidification via acidic atmospheric inputs. After initial physical, chemical, and mineralogical characterization, the soils were analyzed for their ability to adsorb and retain sulfate (SO42-) through a series of batch adsorption and desorption experiments. Reconstructed soil profiles were then subjected to water leaching as the preliminary step to a base release study in which each soil will be placed under simulated acid rain and evaluated for base cation release and subsequent changes in soil chemistry.

Experiments with SO42- adsorption and desorption divide the soils into two categories: (i) shallow surface horizons with high organic matter and little Fe oxide content which had little ability to adsorb additional SO42- and low capacity to retain SO42-; and (ii) deeper subsurface soils with low organic matter and high Fe oxide content which could adsorb SO42- at solution concentrations above 0.5 mmol/L. All soil horizons desorbed SO42- and had no ability for additional adsorption at solution concentrations below 0.5 mmol/L, which implies that the site may be saturated with respect to natural conditions. Initial mass (IM) and Langmiur modeling were used to illustrate SO42- dynamics and make correlations with soil physical, chemical, and mineralogical properties. Fe oxides and Al-saturated organic matter were shown to be the preferential sites for SO42- adsorption but may be already saturated or very near saturation.

Preliminary results from the base release study indicate that the two soils are dominated by different chemical processes and hence release ions into soil solution at different rates. Ion release is shown to be a function of both reactions on the exchange complex and the dissolution of mineral components.
Master of Science

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Guibert, Hervé. "Évolution de la matière organique et de la capacité d'échange cationique des alfisols tropicaux cultivés." Vandoeuvre-les-Nancy, INPL, 1999. http://www.theses.fr/1999INPL086N.

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La pression foncière et l'abandon progressif des jachères caractérisent l'évolution de la plupart des systèmes de culture pratiques dans la zone soudanienne. C’est le cas du bassin cotonnier du Tchad ou des baisses de productions agricoles touchent des zones densément peuplées. L’étude se fonde sur un diagnostic agronomique, des essais longue durée in situ et des analyses de laboratoire avec notamment des fractionnements de la matière organique (MO) du sol. Le diagnostic montre que la teneur en c de l'horizon de surface est un indicateur de productivité du sol au même titre que les taux d'argile, pH, CEC et teneurs en bases échangeables. Le rendement du cotonnier chute à partir de valeurs de teneur en c de 3,4 g kg 1 et de CEC de 2,5 CMOc kg-1. La minéralisation de la MO du sol apparait comme le processus d'évolution majeur affectant la productivité des sols. L’acidification des sols et la lixiviation des bases échangeables surviennent parallèlement, sans affecter aussi fortement la capacité du sol à produire. Des mesures réalisées sur des essais au tchad et en cote d'ivoire comparant des parcelles cultivées avec et sans apports de mo montrent que les variations du taux de mo de l'horizon cultural sont du même ordre de grandeur que les variations spatiales observées dans le diagnostic. Seuls des apports conséquents de fumier maintiennent ce taux juste au dessus du seuil de 3,4 g kg 1. Les enfouissements de MO fraiches ont une efficacité moindre que celle du fumier. Le fractionnement granulométrique de la MO du sol montre que les apports de fumier ou compost permettent d'augmenter les fractions de mo de toute taille, même les fractions de la taille des argiles. La fraction organo-minérale du sol de la taille des argiles participe pour 80% à la CEC des sols, grâce notamment a une CEC d'origine organique par unité de c quatre fois supérieure a celle des fractions de taille supérieures (1000 vs 270 CMOc kg-1. De c). L’application du modèle de Hénin-Dupuis aux fractions confirme que les fractions de la taille des argiles sont plus stables (demi-vie de 17 ans) que celle de la taille des limons (demi-vie de 10 ans) et des sables (demi-vie de 2 ans). Malgré cette relative stabilité, cette fraction de matière organique peut diminuer fortement si aucune gestion organique correcte n'est réalisée sur les parcelles cultivées.

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Gildemeister, Daniela [Verfasser]. "Effects of multivalent cations on the structure of soil organic matter (SOM) / Daniela Gildemeister." Landau : Universitätsbibliothek Landau, 2015. http://d-nb.info/1069181781/34.

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Graouer, Bacart Mareen. "Devenir et transfert de polluants émergents issus du secteur de la santé dans les compartiments sol et eau de l’environnement - Influence de la présence d’éléments traces métalliques." Thesis, Reims, 2014. http://www.theses.fr/2014REIMS008.

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L'objectif général de ce projet est d'apporter des données pertinentes sur le devenir de produits pharmaceutiques dans l'environnement, en particulier aux interfaces eau/sol, afin de mieux suivre les conséquences de leurs utilisations et de leurs rejets. A long terme, les enjeux concernent la protection de l'environnement et de la santé publique. Ces travaux portent sur la caractérisation des propriétés de rétention de cinq médicaments dans des sols calcaires de la région Champagne-Ardenne afin d'évaluer notamment leur potentiel transfert vers les milieux aquatiques. Différents paramètres ont été identifiés comme ayant une influence sur leur rétention. La rétention de l'enrofloxacine dépend fortement du pH et de la force ionique, celle du diclofénac des teneurs en CaCO3 et en matière organique des sols qui ont un effet antagoniste sur son adsorption, celle de la carbamazépine et du sulfaméthoxazole est faible sur un sol calcaire, et enfin la rétention du iopamidol est négligeable. Par ailleurs, l'influence des cations métalliques, polluants ubiquistes des sols, sur la rétention des médicaments a également été étudiée. Les expériences de co-adsorption ont montré que la présence de cuivre et de zinc influence significativement la rétention de l'enrofloxacine, conduisant à une augmentation des quantités adsorbées sur le sol via la formation d'un complexe ternaire de surface, et met ainsi en évidence l'importance de prendre en compte l'interaction des médicaments avec les métaux pour une meilleure compréhension de leur comportement dans les sols. Toutefois, aucune influence notable de la présence de cuivre sur la rétention des autres produits pharmaceutiques n'a été observée
The overall objective of this project is to provide a better knowledge of pharmaceuticals fate in the environment, more particularly at water/soil interfaces, in order to follow the consequences of their use and disposal. The long-term issues concern the protection of the environment and public health. This work focuses on the characterization of retention properties of five pharmaceuticals in calcareous soils of the Champagne-Ardenne region in order to evaluate their potential transfer to water compartments. Various parameters having an influence on their retention were identified. The retention of enrofloxacin is highly affected by pH and ionic strength, diclofenac retention by CaCO3 and organic matter contents of soils which have antagonistic effect on its adsorption, the retention of sulfamethoxazole and carbamazepine is low on a calcareous soil, and iopamidol adsorption is negligible. Moreover, the influence of metal cations, ubiquitous pollutants in soils, on pharmaceuticals retention was also studied. Co-adsorption experiments indicated that the presence of copper and zinc modifies significantly enrofloxacin retention, leading to an increase of adsorbed amounts on the soil via the formation of a ternary surface complex, thus highlighting the importance to take into account the interaction between metals and pharmaceuticals for a better understanding of their behavior in soils. However, no noticeable impact of the presence of copper on other pharmaceuticals retention has been noticed

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17

Sandrin, Todd Ryan. "Naphthalene biodegradation in a cadmium cocontaminated system: Effects of rhamnolipid, pH, and divalent cations." Diss., The University of Arizona, 2000. http://hdl.handle.net/10150/289199.

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Forty percent of hazardous waste sites on the U.S. Environmental Protection Agency's National Priority List (NPL) are cocontaminated with organic and metal pollutants. Conventional approaches to remediating these sites are costly and often ineffective. Bioremediation is a promising, cost-effective alternative but metal toxicity at cocontaminated sites may limit its efficacy. The research described in this dissertation provides two new possible approaches to enhance the bioremediation of cocontaminated environments and sheds light on the relationship between metal concentration and inhibition of organic pollutant biodegradation. In Objective 1, a rhamnolipid biosurfactant was employed to increase naphthalene biodegradation in the presence of cadmium. The biosurfactant reduced bioavailable cadmium concentrations and increased naphthalene bioavailability. Neither of these phenomena, however, fully accounted for the ability of rhamnolipid to reduce cadmium toxicity. The ability of rhamnolipid to alter the cell surface appeared critical to its ability to mitigate toxicity. In Objective 2, pH was lowered to increase naphthalene biodegradation in the presence of cadmium. Reductions in pH had previously been reported to mitigate metal toxicity, but the mechanism of such reductions warranted elucidation. Previous studies implicated the formation of monovalent hydroxylated metal in the mechanism by which pH mediates toxicity. Results of this study, however, suggest that the importance of such species in determining toxicity may be much less than that of the increased competition between hydrogen and metal ions for binding sites on the cell surface at reduced pH. An indirect relationship between metal concentration and inhibition of organic biodegradation was revealed in Objective 3. Naphthalene biodegradation was more sensitive to cadmium concentrations of 10 and 37.5 mg/L than 100 mg/L. For this reason, we investigated whether naphthalene biodegradation could be increased in the presence of a toxic concentration of cadmium by raising the total metal concentration to a higher, but relatively less toxic concentration. Only elevated concentrations of zinc reduced cadmium toxicity. High but less toxic levels of metal may more rapidly induce the transcription of a gene(s) important in metal efflux than lower more toxic concentrations.

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Hao, Xiying. "Diffusive movement and reactions of phosphate and associated cations in an acid soil and in aluminum-rich soil-like systems." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp02/NQ31986.pdf.

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Cooke, James Daniel. "Towards an accurate model of cation binding by soil organic matter." Thesis, Lancaster University, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.444851.

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Linder, Katie Jo. "The Effect of Soil Cation Balancing on Soil Properties and Weed Communities in an Organic Rotation." The Ohio State University, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=osu1449103848.

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RAMBEAU, MAURO ODILE. "REHABILITATION PAR TRAITEMENT CHIMIQUE DE SOLS POLLUES PAR DES CATIONS (Cd, Cr, Cu, Ni, Zn)." Rennes 1, 1993. http://www.theses.fr/1993REN10022.

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Le but de cette these etait de trouver un procede de decontamination des sols pollues par des metaux lourds, realisable in situ, et sans effet sur la matrice du sol ou les nappes phreatiques. De nombreux essais ont montre qu'il n'est pas realisable de determiner une sequence de traitement universelle, et qu'il faut par consequent faire des essais prealables en laboratoire sur des echantillons, avant de s'attaquer aux sols. Une sequence de traitement a base de chlorure d'ammonium iii molaire et d'ammoniaque a toutefois ete retenue pour l'extraction du cadmium, cuivre, zinc, nickel et chrome contenus dans les sols. Cette extraction peut etre optimisee par l'ajout d'acide citrique a la sequence, ceci en prenant garde a la modification de ph engendree dans les sols. Ainsi fait, il ne restera, pour parfaire le traitement qu'a reenrichir les sols en oligo-elements, et eventuellement reajuster le ph

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22

Qian, Yuwei. "Effect of cationic surfactant (CTAB) in the electrokinetic remediation of diesel-contaminated soils." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk2/tape17/PQDD_0004/MQ32224.pdf.

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23

Ahmed, Mohamed Mahmoud. "Réutilisation de fluides pour le traitement des sols contaminés par des hydrocarbures et des cations métalliques." Thesis, Besançon, 2014. http://www.theses.fr/2014BESA2040/document.

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Ce mémoire présente une étude physicochimique sur la réutilisation des fluides de mobilisation pour le traitement de sols contaminés. Cette recherche a été menée afin d’étudier l’efficacité de cette réutilisation et d’évaluer la réduction des coûts opérationnels et des impacts environnementaux. La première partie de ce travail est consacrée au traitement d’hydrocarbures lourds issus de créosote ou de goudrons dans des sols moyennement à fortement contaminés. Plusieurs stratégies ont été développées et évaluées tant pour la réutilisation et l’optimisation d’agents chimiques que pour l’efficacité du fluide de lavage. L’étude du mécanisme d’oxydation des hydrocarbures avec du persulfate a permis d’entrevoir la possibilité de réactions en cascades. Les procédés membranaires d’ultra- et de nano-filtration se sont révélés particulièrement attractifs car préservant l’activité des fluides de traitement après utilisation; Des mesures ont permis d’optimiser à la fois la récupération des substances actives et l’abattement des contaminants. L’étude du mécanisme de mobilisation des hydrocarbures par des mousses de surfactant a montré que les hydrocarbures lourds sont majoritairement extraits dans la phase gazeuse de l’émulsion eau-air. Ces différentes stratégies ont été évaluées au cours de campagnes de terrain. La deuxième partie concerne la réutilisation de solutions diluées d’agents chélatants pour extraire, puis immobiliser des cations métalliques divalents. Plusieurs agents chélatants de la famille des polyaminocarboxylates ont été évalués. La régénération des ligands à partir de résines chélatantes ou de FeS a été évaluée à travers de nombreux cycles de réutilisation
This thesis presents a physico-chemical study devoted to the reuse of remediation fluids for contaminated soil treatment. The aim of this research project was to study the reuse efficiency and to evaluate the reduction of operational costs and environmental impacts. The first part was focused on the treatment of moderately to highly contaminated soils by heavy hydrocarbons from creosote or tar. Several strategies have been developed and evaluated for reuse and optimization of chemical agents. The oxidation mechanism of hydrocarbons with persulphate highlights possible cascade reactions. Ultra- and nanofiltration processes were particularly attractive for activity safe of used treatment fluids; Measurements have been optimized for both active substances recovery and contaminants reduction. The study of hydrocarbons mobilization mechanism by surfactant foams showed that the heavier hydrocarbons are mainly extracted into gaseous phase of water-air emulsion. The different strategies were evaluated during field campaigns. The second part deals with the reuse of chelating agents dilute solutions to extract and then immobilize divalent metal cations. Several chelating agents of polyaminocarboxylates family were evaluated. Regeneration of ligands from chelating resins or FeS was evaluated for many reuse cycles

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Flogeac, Karine Aplincourt Michel. "Etude de la capacité de rétention de produits phytosanitaires par deux solides modèles des sols." Reims : S.C.D. de l'Université, 2005. http://scdurca.univ-reims.fr/exl-doc/GED00000041.pdf.

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Boucher, Patricia. "Base cation immobilization in the stem of some hardwoods of southern Québec." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp03/MQ55039.pdf.

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Bélanger, Nicolas 1971. "Investigating the long-term influence of atmospheric acid deposition and forest disturbance on soil chemistry and cation nutrient supplies in a forested ecosystem of southern Quebec." Thesis, McGill University, 2000. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=36542.

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The objective of this thesis was to validate the dynamic model SAFE (Soil Acidification in Forested Ecosystems) in a small deciduous watershed of southern Quebec. SAFE could then be used to: (1) identify which processes are governing acidification, and (2) assess the rates of acidification according to various forest conditions.
Soil and soil solution chemistry between unburned and burned zones following fire disturbance seventy-five years ago was examined within the watershed. Results showed two major, statistically significant, differences: (1) higher base status, and (2) lower soil solution N in the burned zone. High quality leaf litter of aspen and birch (burned zone) relative to that of sugar and red maple (unburned zone) has contributed to the enrichment of base cations in the forest floor. The enrichment of the forest floor did not however impoverish the B horizon as seen in other studies. Rather, fire enriched the soil in base cations and buffered the effect of forest regrowth in the B horizon.
The MAKEDEP model was used to reconstruct the time-series input files needed to run SAFE. In MAKEDEP, the availability of N determines tree growth which in turn, affects most of the processes involved in nutrient cycling. Regressions of measured deposition at the Hubbard Brook Experimental Forest and that of simulated deposition at the study site suggest MAKEDEP is suitable to model the deposition trends of all elements except Na.
SAFE was calibrated for the unburned and burned conditions at the study site. Fire disturbance and forest regrowth have produced different soil chemical composition within the zones as discussed above. SAFE was therefore validated at the study site as a function of its ability to reproduce soil chemistry under unburned and burned conditions. The simulated soil chemistry was in close agreement with the measured unburned soil conditions, but some processes would have to be clarified or accounted for with greater accurately, e.g., biological N fixation and N immobilization by myccorhizal fungi, to reproduce more accurately the measured burned soil chemistry. Simulated soil chemistry in the unburned zone reinforced nevertheless the conclusions of a few historical soil chemistry studies supporting the hypothesis that acid-sensitive forest sites of the United States underwent significant acidification during 1930--1980 during major input of acidity from the atmosphere. Model output suggests that cation nutrient deficiencies could occur in the long-term, but future Al phytotoxic responses are unlikely to occur due to a relatively high projected pH. (Abstract shortened by UMI.)

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Acker, Marty. "Base cation concentration and content in litterfall and woody debris across a northern hardwood forest chronosequence." Lexington, Ky. : [University of Kentucky Libraries], 2006. http://lib.uky.edu/ETD/ukyfore2006t00460/Acker.pdf.

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Thesis (M.S.)--University of Kentucky, 2006.
Title from document title page (viewed on August 22, 2006). Document formatted into pages; contains: vi, 79 p. : ill. Includes abstract and vita. Includes bibliographical references (p. 71-78).

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Plassard, Frédéric. "Influence de la complexation sur la rétention de trois cations métalliques par un sol alcalin : application à un bassin d'infiltration d'eaux pluviales." Lyon 1, 1999. http://www.theses.fr/1999LYO10005.

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Les techniques de gestion des eaux pluviales urbaines, alternatives aux reseaux unitaires, recourent frequemment aux ouvrages d'infiltration. Les eaux de ruissellement se chargent en polluants, notamment en metaux lourds, et leur infiltration peut generer un risque de contamination du sol et/ou des eaux souterraines. Ce travail a pour objectif une meilleure connaissance des interactions entre les cations metalliques et la zone non saturee en eau d'un sol riche en carbonate, representatif de l'est lyonnais. Notre contribution porte sur la mise en evidence de l'effet des ligands, assimiles a des constituants modeles des eaux pluviales, sur la retention par le sol de trois cations metalliques, cd, pb et zn. Le sol est contamine artificiellement selon deux protocoles de mise en contact complementaires : une approche statique simulant l'etat d'equilibre, en batch, et une approche dynamique, en colonnes non saturees en eau. La speciation des cations dans la phase solide, obtenue par extraction chimique sequentielle, permet d'apprehender les mecanismes de retention. La premiere partie considere les systemes sol/cations metalliques et les experiences permettent : (i) de mettre en evidence l'effet de la concentration initiale du cation metallique sur la retention par le sol ; (ii) de determiner les modes de retention dans le sol et les comportements differents des metaux ; (iii) de souligner les differences entre les deux methodes de mise en contact. La deuxieme partie concerne les systemes sol/cations metalliques/ligands avec trois ligands : les ions chlorure, phtalate et edta. Les profils d'elution en colonne et les speciations permettent : (i) de mettre en evidence l'effet de la nature et de la concentration du ligand sur la quantite de cation metallique retenu et sur la speciation dans le sol ; (ii) de souligner les differences d'effet d'un meme ligand sur les cations metalliques ; (iii) de conforter les hypotheses concernant l'impact du mode de mise en contact.

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El, Make Mahmoud. "Base-cations in relation to weathering of phyllosilicates and forest management in Swedish forest ecosystems /." Uppsala : Swedish Univ. of Agricultural Sciences (Sveriges lantbruksuniv.), 2000. http://epsilon.slu.se/avh/2000/91-576-5899-4.pdf.

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30

Espiau, Pierre. "Contribution à l'étude du complexe absorbant des sols acides à charges mixtes : application aux andosols du Velay." Montpellier 2, 1986. http://www.theses.fr/1986MON20193.

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On cherche a determiner les charges negatives qui se manifestent dans le contexte naturel des sols et les cations echangeables qui les saturent en assurant l'electroneutralite. On s'attache essentiellement a la determination de l'aluminium strictement echangeable et a l'attribution d'une charge moyenne a cet aluminium

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31

Kunhi, Mouvenchery Yamuna [Verfasser]. "Insight into physicochemical structure of soil organic matter by cation interaction and nanothermal properties / Yamuna Kunhi Mouvenchery." Landau : Universitätsbibliothek Landau, 2013. http://d-nb.info/1038673380/34.

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32

Ullberg, Malin. "Effects of pH and Cation Composition on Sorption of Per- and Polyfluoroalkyl Substances (PFASs) to Soil Particles." Thesis, Uppsala universitet, Institutionen för geovetenskaper, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-256415.

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Per- and polyfluoroalkyl substances (PFASs) have drawn great attention recently, due to their environmental persistence, potential toxicity and global distribution. PFAS is a large family of substances, characterized by a perflourinated carbon chain and a functional group. All PFASs are synthetic and have been widely used since the 1950s due to their unique properties of being both hydrophobic and oleophobic, making them useful for many industries. To be able to predict the fate of PFASs in the environment and to obtain detailed understanding of the transport processes, their partitioning behavior between soil particles and water depending on a range of parameters must be investigated. The aims of this study was to investigate the effects of pH, cation composition, functional group and perfluorocarbon chain length on sorption of PFASs to soil particles, by batch sorption experiment in laboratory scale. The laboratory-scale experiments were combined with modelling of the net charge to evaluate if net charge is a good predictor for sorption of PFASs to soil particles. 14 PFASs of varying length and functional groups were studied (PFBA, PFPeA, PFHxA, PFHpA, PFOA, PFNA, PFDA, PFUnDA, PFDoDA, PFTeDA, PFBS, PFHxS, PFOS and FOSA). The effect on sorption of Na+, Ca2+ (two different concentrations) and Al3+ were investigated at pH-range 3-6. Modelling of net charge was carried out in the geochemical model Visual MINTEQ. The soil had 45% organic carbon content. The adsorption of PFASs was strongly correlated with perfluorocarbon chain length, showing a stronger adsorption to particles with increasing perfluorocarbon chain length (i.e. more hydrophobic). The relation between sorption (represented by the distribution coefficient log Kd) and perfluorocarbon chain length was linear for all PFSAs and C3 to C10 PFCAs. The PFSAs (sulfonate functional group) sorbed stronger to soil particles than the PFCAs (carboxylic functional group), and FOSA (sulfonamide functional group) sorbed the strongest. For most PFCAs, (C5-C13) there was a trend of decreasing log Kd (i.e. decreased sorption) with increasing pH, due to pH-dependent changes of the soil particle surfaces. For short and intermediate perfluorocarbon chain length PFCAs (C5-C8) and for PFHxS among the PFSAs, cations had a clear effect on sorption. Aluminium ions (trivalent, Al(NO3)3) had the largest effect, followed by calcium (divalent, Ca(NO3)2) where higher concentration resulted in stronger sorption. Sodium (univalent, NaNO3) had the least influence on sorption. The net charge modelled with Visual MINTEQ takes into account many parameters (including pH) that affect the surface charge and sorption of PFASs to soil particles. When comparing log Kd for the different PFASs with pH and net negative charge, net charge was a better predictor of sorption of PFASs to soil particles than solution pH alone.
Per- och polyfluoroalkylsubstanser (PFAS:er) har dragit stor uppmärksamhet till sig på senare tid, på grund av deras persistenta egenskaper, potentiella toxicitet och globala utbredning. PFAS är en stor grupp ämnen, kännetecknad av en perflourinerad kolkedja och en funktionell grupp. Alla PFAS är syntetiska och har använts i stor utsträckning sedan 1950-talet på grund av deras unika egenskaper av att vara både vatten- och fettavstötande, vilket gör dem användbara för många industriella tillämpningar. För att kunna förutsäga var dessa föroreningars hamnar i miljön och få mer detaljerad förstående för transportprocesserna, måste deras fördelningbeteende mellan jordpartiklar och vattenundersökas för en rad olika parametrar. Syftet med denna studie var att undersöka effekterna av förändrat pH, katjonsammansättning, funktionell grupp och perfluorkolkedjelängd på sorption av PFAS:er till jordpartiklar. Detta gjordes med sorptionsexperiment i laboratorieskala. Laboratorieexperimentet kompletterades med modellering av nettoladdning, för att se huruvida detta väl kunde förklara sorptionen till jordpartiklar. 14 PFAS:er av varierande längd och med tre olika funktionella grupper studerades (PFBA, PFPeA, PFHxA, PFHpA, PFOA, PFNA, PFDA, PFUnDA, PFDoDA, PFTeDA, PFBS, PFHxS, PFOS och FOSA). Effekten på sorption av Na+, Ca2+ (två olika koncentrationer) och Al3+ undersöktes vid pH-intervallet 3-6. Modellering av nettoladdning utfördes i den geokemiska modellen Visual MINTEQ. Jorden som användes hade en halt av organiskt kol på 45%. Adsorptionen av PFAS:er var starkt positivt korrelerad med kedjelängden på de perfluorinerade kolkedjan. Ju längre kolkedja (dvs. mer hydrofob), desto starkare adsorption till partiklar. Relationen mellan sorptionen (här uttryckt som partitioneringskofficienten log Kd) och kedjelängd var linjär för alla PFSA och för C3 till C10 för PFCA. PFSA (sulfonat) adsorberade starkare än PFCA (karboxyl), och FOSA (sulfonamid) adsorberades starkast. För de flesta PFCA, (C5-C13) fanns en allmän trend där log Kd (dvs. sorption) minskade med ökande pH, på grund av pH-beroende förändringar på jordpartiklarna. För korta och medellånga PFCA (C5-C8) och för PFHxS hade katjonsammansättningen en tydlig effekt på sorptionen. Aluminiumjoner (trevärd, Al(NO3)3) hade den största effekten, följt av kalcium (tvåvärd, Ca(NO3)2) där den högre koncentrationen resulterade i starkare sorption. Natrium (envärd, NaNO3) hade minst påverkan på sorptionen till jordpartiklar. Visual MINTEQ tar hänsyn till många parametrar (inklusive pH), när nettoladdningen på jordpartiklarnas yta räknas ut. När log Kd för olika PFAS:er jämfördes med endera pH eller negativ nettoladdning, drogs slutsatsen att nettoladdning korrelerade bättre med sorption än pH.

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33

Flogeac, Karine. "Etude de la capacité de rétention de produits phytosanitaires par deux solides modèles des sols : influence de la présence des cations métalliques : thèse pour le doctorat en sciences spécialité Chimie." Reims, 2004. http://theses.univ-reims.fr/exl-doc/GED00000041.pdf.

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De nombreuses études ont montré que la contamination des eaux de surface et des eaux souterraines résultait, en partie, d'une utilisation massive des produits phytosanitaires. Afin de limiter cette contamination et d'y remédier, il est devenu essentiel de comprendre les processus qui gouvernent le transfert de ces produits vers les milieux aquifères. L'isoproturon, le diméthomorphe et l'amitrole sont trois pesticides largement utilisés en agriculture et en viticulture, notamment en région Champagne-Ardenne. Ils sont très souvent retrouvés dans les eaux à des concentrations non négligeables et représentent une menace pour les nappes phréatiques et l'environnement. La composition des sols (minéraux, matière organique et cations métalliques) joue un rôle essentiel dans la rétention et la mobilité des pesticides. C'est pourquoi il est intéressant d'étudier la rétention des pesticides par les sols ou leurs constituants, ainsi que l'influence des cations métalliques sur cette rétention. C'est dans ce contexte que cette étude a été réalisée sur deux échantillons solides : un résidu lignocellulosique (RLC) choisi comme composé " modèle " de la matière organique des sols, et un échantillon de sol, obtenu après divers traitements, principalement constitué de matières inorganiques. Les cations métalliques étudiés sont le Mn(II), le Fe(III) et le Cu(II), métaux ubiquistes des sols et le Cr(III), métal essentiellement d'origine anthropique
Many studies showed that the contamination of surface and underground waters resulted, partly, of a massive use of the pesticides. In order to limit and to cure this contamination, it seems essential to understand the processes which control the transfer of these products towards the aquifers. Isoproturon, dimetomorph and amitrole are three pesticides widely used in agriculture and vine growing, especially in the Champagne-Ardenne region. These pesticides are often found with significant concentrations in water and represent a risk for the environment. The composition of the soils (mineral, organic matter, and metal cations) plays an essential role in the retention and the mobility of the pesticides. This is why it is interesting to study the retention of the pesticides by the soils or their components, as well as the influence of the metal cations. This study was carried out on two solid samples: a lignocellulosic substrate (LS) which was chosen as "model" compound of soil organic matter, and a soil sample, obtained after various treatments and mainly composed of inorganic matter. The metallic cations studied are the Mn(II), the Fe(III) and the Cu(II), ubiquitous metals in soils, and the Cr(III), a metal of anthropic origin

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Baus, Picard Jorge. "L'Accumulation des cations (K. Ca. Mg. Na et Fe) et l'adaptation de Dittrichia (ex inula) viscosa W. Greuter aux sols acides et calcaires." Grenoble 2 : ANRT, 1986. http://catalogue.bnf.fr/ark:/12148/cb37595770c.

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35

Stewart, Ryan D. "Physical and Chemical Parameters of Common Soils in the Central Plateau Region of Haiti." Thesis, Virginia Tech, 2012. http://hdl.handle.net/10919/32199.

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Soil degradation is a common occurrence in Haiti that is mainly caused by the cultivation of marginal lands and deforestation, which both contribute to the excessive erosion rate seen in the country today. The Central Plateau of Haiti is a mountainous region in which a majority of the population is rural and practices subsistence agriculture on hillsides and steeply-sloping land. Essential plant nutrients, such as nitrogen (N) and phosphorus (P), are commonly a limiting factor in crop production, yet fertilizer is unavailable or is too expensive for smallholder farmers to purchase. This study was conducted to a) evaluate organic matter and nutrient stocks of various soils in the Central Plateau region, along with other chemical and physical characteristics and b) to evaluate the phosphorus-scavenging ability of commonly-grown crops to isolate those that may benefit subsequent smallholder yields. Soils from four locations in the Central Plateau were assessed for organic matter in labile and non-labile fractions as well as for cation exchange capacity (CEC), total organic carbon (C) and N, pH, texture, and other characteristics. Results indicated that most of the soil (92%) was contained within aggregates, and organic matter was mainly present in stable, slowly-decomposing fractions. Seven species were evaluated in a controlled-environment pot experiment for bulk and rhizosphere soil P and pH, plant dry weight, and above- and below-ground P tissue content as indicators of the speciesâ ability to solubilize P from the soil. Velvet bean (Mucuna pruriens (L.) DC) produced the most biomass and was able to take up the most P, though lablab (Lablab purpureous (L.) Sweet), took up comparable amounts of P.
Master of Science
LTRA-6 (A CAPS program for the Central Plateau of Haiti)

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Stewart, Ryan. "Physical and Chemical Parameters of Common Soils in the Central Plateau Region of Haiti." Thesis, Virginia Tech, 2003. http://hdl.handle.net/10919/32199.

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Soil degradation is a common occurrence in Haiti that is mainly caused by the cultivation of marginal lands and deforestation, which both contribute to the excessive erosion rate seen in the country today. The Central Plateau of Haiti is a mountainous region in which a majority of the population is rural and practices subsistence agriculture on hillsides and steeply-sloping land. Essential plant nutrients, such as nitrogen (N) and phosphorus (P), are commonly a limiting factor in crop production, yet fertilizer is unavailable or is too expensive for smallholder farmers to purchase. This study was conducted to a) evaluate organic matter and nutrient stocks of various soils in the Central Plateau region, along with other chemical and physical characteristics and b) to evaluate the phosphorus-scavenging ability of commonly-grown crops to isolate those that may benefit subsequent smallholder yields. Soils from four locations in the Central Plateau were assessed for organic matter in labile and non-labile fractions as well as for cation exchange capacity (CEC), total organic carbon (C) and N, pH, texture, and other characteristics. Results indicated that most of the soil (92%) was contained within aggregates, and organic matter was mainly present in stable, slowly-decomposing fractions. Seven species were evaluated in a controlled-environment pot experiment for bulk and rhizosphere soil P and pH, plant dry weight, and above- and below-ground P tissue content as indicators of the speciesâ ability to solubilize P from the soil. Velvet bean (Mucuna pruriens (L.) DC) produced the most biomass and was able to take up the most P, though lablab (Lablab purpureous (L.) Sweet), took up comparable amounts of P.
Master of Science
LTRA-6 (A CAPS program for the Central Plateau of Haiti)

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37

Migeon, Aude. "Etude de la variabilité naturelle dans la réponse du peuplier aux métaux : Bases physiologiques et exploitation en phytoremédiation." Thesis, Nancy 1, 2009. http://www.theses.fr/2009NAN10050/document.

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Les différentes études entreprises ont porté sur la détermination du potentiel accumulateur du peuplier à une fin d’utilisation en phytoremédiation. Chez les végétaux, les éléments traces comme le Zn, Fe, Cu, Co, Mn, Mo et Ni sont nécessaires aux processus biologiques mais leur accumulation excessive peut être toxique. D’autres éléments non essentiels comme le Cd et le Pb peuvent également être absorbés par les végétaux, et donc constituer un danger potentiel puisqu’ils entrent ainsi dans la chaîne alimentaire. La phytoremédiation est l’utilisation de plantes et de leurs microbes associés pour la dépollution de l’environnement. Dans le cadre de cette étude, il a été démontré que le peuplier (Populus spp.) pouvait accumuler de relativement fortes concentrations de certains métaux (Cd, Zn et Ni) par rapport à d’autres espèces ligneuses, par exemple 30-50 µg de Cd /g de matière sèche foliaire, soit 20 fois plus que les autres espèces. Après avoir mis en évidence le potentiel accumulateur du peuplier, nous avons testé différents cultivars en culture hydroponique et avons ainsi mis en évidence des potentiels accumulateurs variés entre cultivars. Nous avons montré que les hybrides de P. trichocarpa accumulaient davantage que les autres hybrides. Parallèlement à cette étude, nous avons implanté ces mêmes cultivars sur deux sites pollués dans le cadre du projet ANR PHYTOPOP. Combiné à la production d’une forte biomasse qui peut être utilisée pour produire de l’énergie, ce caractère accumulateur fait du peuplier un bon candidat pour la phytoremédiation. Les membres de la famille des CDF (Cation Diffusion Facilitator) sont impliqués dans le transport des métaux. Après une étude phylogénétique des membres de cette famille (démonstration d’un nombre supérieur de CDF chez le peuplier par rapport aux autres espèces), leur expression dans différents tissus et dans différentes conditions physiologiques (sur sol témoin et sur sol pollué) a été étudiée. De plus, la caractérisation fonctionnelle a permis de mettre en évidence un transporteur de Zn (PtMTP2) et un transporteur de Mn (PtMTP9). Une tentative de localisation de ces transporteurs a également été entreprise. Dans le but de localiser les métaux dans les tissus de la plante, nous avons effectué des analyses en spectrométrie de masse à ionisation secondaire (SIMS) sur des feuilles de peupliers soumis à un stress métallique. Cette dernière technique a permis de montrer que le Zn était essentiellement concentré au niveau du mésophylle
The present study beared on the capacity of poplar to be used in phytoremediation programmes. In plants, trace elements such as Zn, Fe, Cu, Co, Mn, Mo and Ni are necessary to biological processes but they also can be toxic when present at high concentrations. Other non essential elements, such as Cd and Pb also can be taken up by plants and therefore constitute a potential risk for health via accumulation into the food chain. Phytoremediation is the use of plants and associated microorganisms to clean up the environment. First, we have shown that poplar (Populus) species could relatively accumulate high concentrations of metals (Cd, Zn and Ni) compared to other woody plants. For instance, poplar is able to accumulate 30 times more Cd than other woody species. Second we have measured in hydroponic cultures, the potential of metal accumulation by different poplar cultivars. We found that P. trichocarpa hybrids accumulated more metals than the other hybrids. As part of the PHYTOPOP programme, we have also grown the same cultivars on two different polluted sites. Finally, by secondary ion mass spectrometry, we were able to localize Zn in poplar leaf mesophyll. The high biomass, which can also be used for energetic processes, and the heavy metals accumulation properties of poplar lead to the conclusion that poplar can constitute a good candidate for phytoremediation. The CDF (Cation Diffusion Facilitator) members are proteins involved in the transport of heavy metals. Phylogenetic analyses of the CDF family have shown that poplar contains a higher number of CDF members compared with other species. Expression levels of CDF members were studied in different tissues and in different physiological conditions. Moreover, heterologous expression in yeast has shown that PtMTP2 and PtMTP9 transport Zn and Mn respectively. Localization experiments in planta were also realized

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38

Lima, Eduardo do Valle [UNESP]. "Plantas de cobertura e calagem superficial na fase de implantação do sistema de plantio direto em região de inverno seco." Universidade Estadual Paulista (UNESP), 2004. http://hdl.handle.net/11449/99955.

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
Atualmente vem existindo interesse na calagem superficial, sem prévia incorporação, para implantação do sistema de plantio direto (SPD). Dessa forma, objetivou-se avaliar a quantidade, a qualidade e os efeitos de resíduos de diferentes plantas de cobertura, com e sem calagem superficial, sobre os atributos químicos no perfil do solo e as respostas do milho e da soja, no SPD em fase de implantação em região de inverno seco. O experimento foi realizado nos anos agrícolas de 1999/00, 2000/01 e 2001/02 na FCA/UNESP-Botucatu (SP), em Nitossolo Vermelho Distroférrico. O delineamento experimental foi em blocos ao acaso, com parcelas subdivididas e quatro repetições. As parcelas foram constituídas pelos tratamentos de cobertura vegetal, sendo: 1-sorgo de Guiné vermelho, 2-sorgo de Guiné branco/preto, 3-milheto, 4-painço, 5-vegetação espontânea e 6-sem vegetação. Nas subparcelas foram admitidos dois níveis de saturação por bases: A- a original do solo e B- visando a elevação da V% a 70 (recebendo inicialmente uma aplicação superficial de calcário e posterior reaplicação). Foi utilizado um calcário dolomítico faixa D (filler). As coberturas vegetais foram dessecadas aos 53, 56 e 50 dias após a emergência...
Interest has been on the rise toward surface liming, without previous incorporation, during no-till system implementation. The objective was thus to evaluate the amount, quality, and effects of residues of different ground cover plants, either with or without surface liming, on the soil profile's chemical attributes, and the responses of corn and soybean, under no-till system at the implementation stage in a dry-winter region. The experiment was conducted during the 1999/00, 2000/01, and 2001/02 cropping seasons at FCA/UNESP-Botucatu (SP), on a Red Nitosol (Alfisol). The experimental design was organized as random blocks, with split-plots and four replicates. Plots consisted of ground cover plant treatments, as follows: 1-red broomcorn millet, 2- white/black broomcorn millet, 3- millet, 4- fall panicum, 5-spontaneous vegetation, and 6-no vegetation. Two base saturation levels were admitted in the subplots: A- the soil's original value, and B- a value that would raise V% to 70 (initially receiving one surface lime application and a later reapplication). Ground cover plants were desiccated at 53, 56, and 50 days after emergence, in the three cropping years... (Complete abstract, click electronic address below)

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39

Ferreira, Raquel Sofia e. Vasconcelos. "Wildfire effects on soil nutrients stocks and exports by overland flow." Doctoral thesis, Universidade de Aveiro, 2016. http://hdl.handle.net/10773/16825.

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Doutoramento em Ciências e Engenharia do Ambiente
O objetivo deste trabalho foi realizar uma avaliação de perdas de nutrientes após incêndio por escorrência superficial, à escala de microparcela e à escala de encosta (embora de forma limitada) numa área recentemente queimada da região Mediterrânica, fornecendo estimativas das exportações de catiões, azoto e fósforo, num enquadramento paisagístico como este propenso ao fogo. Representa um importante complemento para o até agora modesto número de estudos sobre as perdas de nutrientes pós-fogo por escorrência superficial, realizado na região Mediterrânica, para antecipar os impactos dos incêndios recorrentes na produtividade do solo. Este trabalho é parte do projeto FIRECNUTS (PTDC/AGR-CFL/104559/2008) - efeitos de um incêndio nas reservas de nutrientes, dinâmica e exportações – e lida com estas lacunas de pesquisa, estudando a exportação de nutrientes selecionados (catiões, azoto e fósforo) numa área florestal recentemente queimada, no centro-norte de Portugal (Sever do Vouga). Os objetivos específicos foram comparar as exportações de catiões, assim como de azoto e fósforo nas formas totais e solúveis, principalmente à escala de micro-parcela: (i) para duas das espécies de árvores mais propensas ao fogo, i.e. eucalipto e pinheiro; (ii) para duas das geologias mais comuns na área, i.e. granito e xisto; (iii) para diferentes orientações do declive, i.e. face a norte e face a sul; (iv) com tempo-desde-incêndio durante os meses iniciais após incêndio e durante um período de monitorização mais extenso. As exportações de nutrientes foram particularmente acentuadas nos três meses após o fogo. No entanto, após este período inicial, foram observados também picos nas concentrações de nutrientes, em associação a eventos de precipitação intensa, com diferenças na variação de cada nutriente, e com o declínio das exportações de fósforo a seguir um padrão mais linear com o tempo desde o incêndio. Os resultados deste estudo enfatizaram a importância de uma camada protetora do solo (ou seja, com as agulhas das árvores queimadas de pinheiro) para minimizar a exportação de nutrientes pósfogo. A geologia também foi identificada como uma variável importante na avaliação de riscos de erosão pós-incêndio e na definição de medidas de conservação do solo. A orientação do declive não foi uma variável decisiva neste estudo. Estes resultados mostram também que as escalas de tempo mais amplas são úteis para obter mais conhecimento sobre o ciclo hidrológico dos nutrientes e os complexos processos que ocorrem nas áreas de floresta queimada.
The aim of this work was to perform an evaluation of post-fire nutrient losses by overland flow at micro-plot scale, and at slope scale (although on a limited basis) in a recently burnt Mediterranean area, providing estimates of the range of base cations, nitrogen and phosphorus exports in a fire-prone landscape. It represents an important add-on to the up to now modest number of studies on post-fire nutrient losses by overland flow conducted in the Mediterranean region, for anticipating the impacts of recurrent fires on soil productivity. This work is part of the FIRECNUTS project (PTDC/AGR-CFL/104559/2008) - WildFIRE effects on topsoil Carbon and NUTrient Stocks, dynamics and exports – and addresses these research gaps by studying the export of selected nutrients (base cations, nitrogen and phosphorus) in a recently burnt forest area in northcentral Portugal (Sever do Vouga).The specific objectives were to compare base cations exports together with nitrogen and phosphorus exports in the total and soluble forms by overland flow mainly at the micro-plot scale: (i) for the two predominant and fire-prone forest types in north-central Portugal, i.e. eucalypt and pine plantations; (ii) for the two prevailing parent materials in the region, i.e. granite and schist; (iii) for two different slope aspects, i.e. a slope facing north and a slope facing south; (iv) with time-since-fire during the initial months of the window-ofdisturbance and for an extended monitoring period. In parallel, nitrogen and phosphorus stocks in the topsoil were also compared. Nutrient exports were particularly pronounced in the three months after fire. However, after this initial period, peaks in nutrients concentrations were also observed in association to intense rainfall events, with differences in the variation of each nutrient, with phosphorus exports decline following a more straightforward pattern with time since fire. The results of this study emphasized the importance of a protective soil layer (i.e. of scorched pine needle) for minimizing post-fire nutrient export. Parent material was also found to be an important variable when assessing post-fire erosion risks and defining soil conservation measures. Slope aspect was not a decisive variable in his study. These results also show that broader time scales are useful to gain insight into the hydrological and nutrient cycle complex processes in burnt forest areas.

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40

Schoen, Robert. "Transferts de solutés dans un lysimètre en conditions controlées : expériences et simulations." Phd thesis, Grenoble 1, 1996. http://www.theses.fr/1996GRE10212.

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Les etudes du transfert de solutes dans les sols realisees en laboratoire (colonnes de sol) ne sont pas totalement representatives des conditions de terrain (variabilite spatiale, structuration du sol). D'un autre cote, les etudes de terrain a grande echelle permettent difficilement de quantifier les flux et les mecanismes. Une approche intermediaire est proposee, avec un lysimetre (1,7 m#3) de sol peu remanie, sur lequel on controle les conditions aux limites imposees. On utilise un flux hydrique constant de l'ordre de 1mm/h. Des solutes sont introduits sous forme de creneaux de concentration. Les especes utilisees sont: #2h#2o, h#2#1#8o, i#-, cl#-, br#-, comme traceurs, et atrazine, k#+, nh#4#+, no#3#-, comme especes interactives et/ou reactives. L'analyse des courbes d'elution obtenues permet l'identification des mecanismes preponderants et le chiffrage des parametres pertinents. Les outils utilises pour cela sont les modeles fondes sur la convection-dispersion (cd et mim), le modele convectif a fonction de transfert lognormale (clt), et le modele couple transport-chimie impact. Les resultats montrent qu'une partie de l'eau ne participe pas a l'ecoulement. Ainsi, les hypotheses classiquement admises dans le modele cd sont dans ce cas invalidees. L'exclusion anionique provoque une sortie precoce des traceurs anioniques par rapport aux traceurs isotopiques. L'ammonium apporte est majoritairement nitrifie. Le potassium subit des echanges cationiques avec le calcium et le magnesium. Dans nos conditions d'essai, la restitution de l'atrazine a la sortie du monolithe est importante et sa degradation faible. La derniere experience est realisee en interrompant l'alimentation en eau avant l'apparition des solutes a la sortie. Le prelevement de 400 echantillons de sol au sein du lysimetre donne une image des distributions de teneur en eau et de concentration, qu'on peut comparer aux courbes d'elution. L'interpretation revele une forte variabilite spatiale et tend a suggerer l'occurence d'ecoulements preferentiels que l'utilisation de colonnes de petite taille peut occulter

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Barbier, Frédérique. "Rétention du plomb(II) et du cadmium(II) par une barrière argileuse : transferts métalliques et influence de la complexation." Lyon 1, 1999. http://www.theses.fr/1999LYO10256.

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La mise en decharge sans traitement prealable est la methode d'elimination des dechets solides la plus ancienne et la plus repandue. L'ecoulement des eaux de ruissellement conduit alors a la formation de lixiviats contenant des polluants mineraux et organiques. Les textes reglementaires imposent d'impermeabiliser les fonds de decharges par une double barriere afin d'eviter la contamination des sous-sols par ces lixiviats. La premiere barriere, active, est constituee d'un systeme de drains et d'une geomembrane. La seconde, passive, est constituee d'une couche d'argile impermeable permettant de retenir les polluants. L'objectif de ce travail est d'etudier la retention de deux cations metalliques, pb(ii) et cd(ii), par des argiles de type bentonite, puis d'evaluer l'impact des phenomenes de complexation sur cette retention. Deux montmorillonites sont selectionnees : une argile technique destinee a l'etancheification des fonds de decharge, et une argile de reference. La premiere partie decrit un mode d'adsorption statique en batch, permettant de determiner les caracteristiques acido-basiques des argiles et de modeliser les mecanismes de retention des cations metalliques a la surface des montmorillonites. La deuxieme partie, plus appliquee, rassemble les resultats obtenus lors de percolations en colonnes et permet d'apprehender le transfert des polluants metalliques, complexes ou non, a travers un milieu poreux modele, en liaison avec la charge et la stabilite conditionnelle des especes complexes.

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Bigorre, François. "Influence de la pédogenèse et de l'usage des sols sur leurs propriétés physiques : mécanismes d'évolution et éléments de prévision." Nancy 1, 2000. http://www.theses.fr/2000NAN10239.

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Les besoins croissants de données sur le comportement hydrique des sols face au peu de données mesurées ont conduit à estimer les propriétés hydriques des sols à partir de données plus courantes (essentiellement granulométrie et matière organique). Dans ce contexte, ce travail visait à déterminer mieux connaître les effets partagés du développement pédologique et de l'usage des sols sur leurs propriétés de rétention d'eau. L'objectif final était d'intégrer de nouvelles variables dans les fonctions d'estimation des propriétés hydriques des sols. Notre démarche a consisté à comparer les propriétés de sols identiques au plan de leur pédogenèse, sous couvert forestier et sous culture, de façon à quantifier l'impact de l'usage des sols sur leurs propriétés. Le cadre de l'étude a été une séquence de sols de l'Est de la France développée sur un substrat calcaire (plateaux du Dogger) relativement homogène. La séquence d'évolution est classique à savoir qu'elle implique la succession des processus de décarbonatation, de décalcification et de lessivage. L'étape décisive de l'évolution des sols apparaît celle du lessivage car elle montre clairement une évolution des sols tant au plan de la nature des constituants que de leur environnement géochimique. Des variations de CEC en fonction du pH, jusqu'à 50%, ont été attribuées à la présence de charges variables sur les constituants du sol. Des limites de comportement correspondant aux trois étapes de l'évolution ont été définies en fonction du pH et du taux de saturation en cations. [. . . ]In fine, ce mémoire démontre que l'horizon de sol, qu'il soit cultivé ou sous forêt est l'unité de base à partir de laquelle les propriétés physiques, mais aussi physico-chimiques doivent· être raisonnées. Dès lors que des unités de sols ont été définies et caractérisées au plan de leurs propriétés, et sous réserve que les sols appartiennent à un contexte similaire, des fonctions de pédotransfert simplifiées peuvent être définies. Ce travail ouvre donc la voie à la valorisation de données provenant de bases de données ou de cartes établies à partir de critères morpho-génétiques du référentiel pédologique français ou encore de la classification des sols de 1967 (CPCS).

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43

Lima, Eduardo do Valle 1970. "Plantas de cobertura e calagem superficial na fase de implantação do sistema de plantio direto em região de inverno seco /." Botucatu : [s.n.], 2004. http://hdl.handle.net/11449/99955.

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Orientador: Carlos Alexandre Costa Crusciol
Banca: Dirceu Maximino Fernandes
Banca: Luis Reynaldo F. Alleoni
Banca: Edson Lazarini
Banca: Julio Cezar F. dos Santos
Resumo: Atualmente vem existindo interesse na calagem superficial, sem prévia incorporação, para implantação do sistema de plantio direto (SPD). Dessa forma, objetivou-se avaliar a quantidade, a qualidade e os efeitos de resíduos de diferentes plantas de cobertura, com e sem calagem superficial, sobre os atributos químicos no perfil do solo e as respostas do milho e da soja, no SPD em fase de implantação em região de inverno seco. O experimento foi realizado nos anos agrícolas de 1999/00, 2000/01 e 2001/02 na FCA/UNESP-Botucatu (SP), em Nitossolo Vermelho Distroférrico. O delineamento experimental foi em blocos ao acaso, com parcelas subdivididas e quatro repetições. As parcelas foram constituídas pelos tratamentos de cobertura vegetal, sendo: 1-sorgo de Guiné vermelho, 2-sorgo de Guiné branco/preto, 3-milheto, 4-painço, 5-vegetação espontânea e 6-sem vegetação. Nas subparcelas foram admitidos dois níveis de saturação por bases: A- a original do solo e B- visando a elevação da V% a 70 (recebendo inicialmente uma aplicação superficial de calcário e posterior reaplicação). Foi utilizado um calcário dolomítico faixa D (filler). As coberturas vegetais foram dessecadas aos 53, 56 e 50 dias após a emergência... (Resumo completo, clicar acesso eletrônico abaixo)
Abstract: Interest has been on the rise toward surface liming, without previous incorporation, during no-till system implementation. The objective was thus to evaluate the amount, quality, and effects of residues of different ground cover plants, either with or without surface liming, on the soil profile's chemical attributes, and the responses of corn and soybean, under no-till system at the implementation stage in a dry-winter region. The experiment was conducted during the 1999/00, 2000/01, and 2001/02 cropping seasons at FCA/UNESP-Botucatu (SP), on a Red Nitosol (Alfisol). The experimental design was organized as random blocks, with split-plots and four replicates. Plots consisted of ground cover plant treatments, as follows: 1-red broomcorn millet, 2- white/black broomcorn millet, 3- millet, 4- fall panicum, 5-spontaneous vegetation, and 6-no vegetation. Two base saturation levels were admitted in the subplots: A- the soil's original value, and B- a value that would raise V% to 70 (initially receiving one surface lime application and a later reapplication). Ground cover plants were desiccated at 53, 56, and 50 days after emergence, in the three cropping years... (Complete abstract, click electronic address below)
Doutor

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Brigham, Russell D. "Assessing the Effects of Lake Dredged Sediments on Soil Health: Agricultural and Environmental Implications on Midwest Ohio." Bowling Green State University / OhioLINK, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=bgsu1593902126203743.

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45

Merdy, Patricia. "Etude de la complexation et de la sorption des cations Mn(II), Cu(II) et Fe(III° par une lignine et différents modèles moléculaires : influence de la teneur en ions calcium et carbonate présents dans les sols de craie." Reims, 2001. http://www.theses.fr/2001REIMS025.

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Le rôle des cations métalliques dans les processus de biodégradation de la lignine est peu connu. Ces cations sont certainement impliqués, en complément à l'action des enzymes et des microorganismes, dans des réactions radicalaires dégradatives. De plus, le transport des ions dépend de la présence de lignine qui va déterminer en partie leur concentration et leur spéciation dans les sols. Dans ce contexte, nous nous sommes attachés à l'étude des interactions entre une lignine de paille de blé et les cations métalliques Cu(II), Fe(III) et Mn(II), très abondants dans les sols. Afin de comprendre les phénomènes se produisant spécifiquement dans les sols de craie, caractéristiques de la région Champagne-Ardenne, l'influence de la teneur en ions calcium et carbonate sur la complexation des métaux de transition par la lignine, a également été étudiée. Dans un premier temps, étant donné la complexité structurale de la lignine, l'étude a été réalisée sur des molécules modèles simples, représentatives des motifs structuraux trouvés dans la lignine native : trois acides cinnamiques (précurseurs de la lignine), l'alcool coniférylique et un dimère. Cette étude a été menée en solution aqueuse afin de rendre compte des phénomènes de complexation en solution se produisant dans les sols avec des fractions solubles de lignine. Dans un second temps, trois modèles polymériques ont été étudiés : un déhydropolymère (lignine de synthèse) et deux substrats extraits de la paille de blé. De nombreuses techniques physico-chimiques (RMN du solide, potentiométrie, XPS, etc) ont été mises en œuvre pour caractériser préalablement ces trois solides.

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Lopes, Otavio Mitsuhiro Motizuki. "Efeito de agromineral e vinhaça em atributos químicos de dois tipos de solos." Universidade Federal de São Carlos, 2013. https://repositorio.ufscar.br/handle/ufscar/18.

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Can vinasse accelerate the change of minerals in rock powder for obtaining fertilizer, with utilization of residues from alcohol agro and mining industries? Answering this question was the main objective of this study. So, it was carried out two experiments in a laboratory in a completely randomized set using PVC columns in which we reproduced the 0-50 cm layers of a very clayey Red Oxisol and a Quartzipsamment. In the first test, with duration of 30 days, it was evaluated the application form of the mixture into the soil. It were tested incorporation of basalt powder previously in soil and incubation of basalt powder and vinasse in the laboratory for 24 hours and then applied to the soil. In Red Oxisol were used two doses of basalt powder (0 and 2,0 t ha-1), a dose of vinasse (200 m3 ha-1) and as a control, a dose of water (200 m3 ha-1) using the same amounts of rock powder. For this test, samples were collected from the surface of the columns in 1, 7, 15 and 30 days of experiment. In the second test, with duration of 90 days, using the two soils, were added three doses of basalt powder (0, 2,0 and 4,0 t ha-1) and a dose of vinasse (200 m3 ha-1). The control was made by treatments with water (200 m3 ha-1) with the same doses of rock powder. Samples were collected on the surface of each column in 1, 15, 30, 45, 60 and 90 days and at the end of the experiment, in botton and in the leachate. For the surface samples in the first and second tests and the botton in the second test, we determined the levels of macronutrients (P, K, Ca, Mg, S), micronutrients (B, Fe, Cu, Mn, Zn), H + Al, Al, organic matter, pH in CaCl2, sum of bases, base saturation and cation exchange capacity. In the leachate were determined Ca, Mg, K, SO4, Fe, Mn and Zn. In the first test, the evaluation of the application form of the mixture indicated that there was no difference between the use of basalt powder and vinasse incubated for 24 hours or previously incorporation of rock powder in the soil and then application of vinasse. In the second test, there were significant effects of solvent and soil in the surface layer, with variations in the levels of the attributes analyzed over time. The dose of basalt powder was not significant for most attributes analyzed, except for the levels of boron and iron. On balance levels at the beginning and end of the experiment, the results suggest that sorption phenomena with neoformed mineral phases or organic acids may have occurred. The mixture of vinasse and rock powder is an alternative fertilizer and reduces the consumption of soluble fertilizers, but further studies are needed to evaluate the sorption phenomena and availability of cations in the mixture.
Vinhaça pode acelerar a alteração de minerais em pó de rocha para obtenção de fertilizantes, com aproveitamento de resíduos de agroindústrias de álcool e de mineradoras? Responder a esta pergunta foi o principal objetivo deste estudo. Assim, foi montado em laboratório dois ensaios inteiramente casualizados em colunas de PVC nas quais foram reproduzidas as camadas 0-50 cm de um Latossolo Vermelho muito argiloso e de um Neossolo Quartzarênico. No primeiro ensaio, com duração de 30 dias, foi avaliado o modo de aplicação da mistura no solo. Foram testados a incorporação de pó de basalto previamente no solo e a incubação de pó de basalto e vinhaça em laboratório por 24 horas e depois aplicação no solo. Em Latossolo, foram utilizadas duas doses de pó de basalto (0 e 2,0 t ha-1), uma dose de vinhaça (200 m3 ha-1) e como controle uma dose de água (200 m3 ha-1) com as mesmas quantidades de pó de rocha. Para este ensaio foram coletadas amostras da camada superficial das colunas aos 1, 7, 15 e 30 dias de experimento. No segundo ensaio, com duração de 90 dias, utilizando os dois solos, foram adicionadas três doses de pó de basalto (0; 2,0 e 4,0 t ha-1) e uma dose de vinhaça (200 m3 ha-1). O controle foi feito por meio de tratamentos com água (200 m3 ha-1) e com as mesmas doses de pó de rocha. Foram coletadas amostras na superfície de cada coluna aos 1, 15, 30, 45, 60 e 90 dias e, ao final do experimento, em profundidade e no lixiviado. Para as amostra em superfície do primeiro e segundo ensaios e em profundidade do segundo ensaio, foram determinados os teores de macronutrientes (P, K, Ca, Mg, S), micronutrientes (B, Fe, Cu, Mn, Zn), H+Al, Al, matéria orgânica, pH em CaCl2, soma de bases, saturação por bases e capacidade de troca catiônica. No lixiviado foram determinados os teores de Ca, Mg, K, SO4, Fe, Mn e Zn. No primeiro ensaio, a avaliação do modo de aplicação da mistura indicou que não houve diferença entre a utilização do pó de basalto incubado em vinhaça por 24 horas ou incorporação do pó de rocha no solo e em seguida aplicação de vinhaça. Já no segundo ensaio, houve efeito significativo do solvente e do solo na camada superficial, com variações nos teores dos atributos analisados durante o tempo. A dose de pó de basalto não foi significativa para a maioria dos atributos analisados, com exceção dos teores de boro e de ferro. No balanço de teores no início e no fim do experimento, os resultados sugerem que fenômenos de sorção com fases minerais neoformadas ou com ácidos orgânicos podem ter ocorrido. A mistura de vinhaça e pó de rocha é uma alternativa de adubação e permite reduzir o consumo de fertilizantes solúveis, mas são necessários estudos complementares para avaliar fenômenos de sorção e de disponibilização de cátions nessa mistura.

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Briedis, Clever. "Compartimentos da matéria orgânica do solo, agregação, mecanismos de proteção e sequestro de carbono influenciados pela calagem superficial em sistema plantio direto." UNIVERSIDADE ESTADUAL DE PONTA GROSSA, 2010. http://tede2.uepg.br/jspui/handle/prefix/2202.

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Liming is the most often practice used to neutralize soil acidity, and also promotes chemical changes that can alter the soil organic matter (SOM) pools and the mechanisms of flocculation, formation and stabilization of macro-and microaggregates. The objective of this study was to evaluate carbon sequestration, in the whole and in the aggregates samples, and the changes in the SOM pools affected by liming in a long-term no-tillage. The experiment was conducted in an Oxisol, located in Ponta Grossa, PR. The experimental design was a randomized complete block, arranged as split plot with three replications. The main plot consisted of dolomite lime applied on the soil surface at a 0 or 6 Mg ha-1 in 1993, and 0 or 3 Mg ha-1 in 2000 in plots previously with and without lime, and the treatments was assigned as: 0+0, 6+0, 0+3 and 6+3 Mg ha-1. The subplots were represented by sampling depth and consist of 0-2.5, 2.5-5, 5-10 and 10-20 cm layer. The soil samples were taken in September 2008 and the total organic carbon (TOC) was analyzed in the whole sample, in the aggregates and in the particulate organic carbon (POC) and in the fraction associated with minerals carbon (OCAM). Aggregates of 8-19 mm, in the 0-2.5 cm layer were analyzed by using scan microscope spectrometer X-ray (EDS) for elemental analysis of carbon (C) and calcium (Ca). Liming promoted accumulation of TOC mainly in the layer 0-2.5 cm. The TOC stocks at 0-20 cm were 49.9, 52.9, 52.7 and 57.5 Mg ha-1 for 0+0, 6+0, 0+3, 6 +3 treatments, respectively. Stocks in the SOM fractions were also increased with liming. The increase in POC stock was close relationship (R2 = 0.98, P = 0.011) with the C accumulated input through crop residue, which was higher in plots that were limed. A positive correlation was found between TOC and C extracted in hot water (CHW), total polysaccharides (TP) and labile (LP). Correlations also showed that TOC had a closer relationship with POC than with OCAM, suggesting a greater influence on the labile fraction of TOC increase with liming. In aggregate, the effect of liming in TOC accumulation was mainly in 0-2.5 cm depth. The treatments with liming showed high mean weight diameter (MWD), which provided a large stock of TOC in the 8-19 mm aggregate size. A higest proportion of large aggregates with liming was closely correlated with the TOC content of whole sample. The highest liming dosis resulted in both COP and in OCAM, in the largest class of aggregates. The proportion of POC average of the treatments in relation to OCAM, this class of aggregates, has decreased in depth, and were 18, 13, 10 and 8% at depths of 0-2.5, 2.5-5, 50-10 and 10-20, respectively. Elemental analysis of C and Ca showed a positive correlation of those elements contained in a section of clay from the center of 8-19 mm aggregates. The results suggest that application of lime in soil with clay fraction dominated by kaolinite, brings benefits to structuring and promotes an increase of C in the whole sample and in aggregates.
A calagem é a prática mais utilizada para neutralizar a acidez do solo, porém promove também modificações químicas capazes de alterar os compartimentos da matéria orgânica do solo (MOS) e mecanismos de floculação, formação e estabilização de macro e microagregados. O objetivo desse trabalho foi avaliar o seqüestro de carbono, na amostra integral e nos agregados, e as alterações nos compartimentos da MOS afetados por calagem superficial em sistema plantio direto de longa duração. O experimento foi conduzido em um Latossolo Vermelho textura média, no município de Ponta Grossa, PR. O delineamento experimental foi o de blocos completos ao acaso em parcelas subdivididas, com três repetições. As parcelas consistiram da aplicação de calcário dolomítico na superfície do solo na dose de 0 ou 6 Mg ha-1 em 1993, e dose de 0 ou 3 Mg ha-1 em 2000 nas parcelas previamente com e sem calcário, compondo os tratamentos: 0+0; 6+0; 0+3 e 6+3 Mg ha-1. As subparcelas foram constituídas pelas profundidades de coleta, sendo realizadas em 0-2,5, 2,5-5, 5-10 e 10-20 cm de profundidade. As coletas de solo foram realizadas em setembro de 2008 e analisados os conteúdos de carbono orgânico total (COT) na amostra total, nos agregados e nas frações particulada (COP) e associada aos minerais (COAM) da matéria orgânica do solo (MOS). Agregados de 8-19 mm, da camada 0-2,5 cm, foram analisados através do uso de espectrômetro de dispersão de raios X (EDS) para a análise elementar de carbono (C) e cálcio (Ca). A calagem promoveu acúmulo de COT, principalmente na camada 0-2,5 cm. Os estoques de COT na camada de 0-20 cm foram 49,9, 52,9, 52,7 e 57,5 Mg ha-1 para os tratamentos 0+0, 6+0, 0+3 e 6+3, respectivamente. Os estoques nas frações da MOS também foram aumentados com a calagem. O aumento no estoque de COP foi estreitamente relacionado (R2=0,98; P=0,011) com a adição acumulada de C via resíduo cultural, a qual foi mais elevada nas parcelas que receberam calagem. Houve correlação positiva entre COT e carbono em água quente (CAQ), polissacarídeos totais (PT) e lábeis (PL). Correlações também demonstraram que o COT teve relação mais estreita com o COP do que com COAM, sugerindo maior influência da fração lábil no aumento de COT com a calagem. Nos agregados, a calagem proporcionou acúmulo de COT principalmente na profundidade de 0-2,5 cm. A calagem aumentou o diâmetro médio ponderado (DMP), proporcionando grande estoque de COT na classe de agregado 8-19 mm. A elevada proporção de agregados grandes nos tratamentos com calagem foi estreitamente correlacionado com o conteúdo de COT da amostra integral. A maior dose de calcário proporcionou aumento no estoque de COT tanto em COP quanto em COAM, visto principalmente na maior classe de agregados. A proporção de COP em relação ao COAM, na média dos tratamentos, nessa classe de agregados, diminuiu em profundidade, ficando em torno de 18, 13, 10 e 8 % nas profundidades de 0-2,5, 2,5-5, 5-10 e 10-20, respectivamente. Análise elementar de C e Ca demonstraram correlação positiva dos dois elementos contidos em uma secção da fração argila do centro de agregados de 8-19 mm. A aplicação de calcário, em solo dominado na fração argila por caulinita, traz benefícios à estruturação e promove aumento de C na amostra integral e nos agregados.

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Starostová, Anna. "Vodní-kationické můstky v půdní organické hmotě." Master's thesis, Vysoké učení technické v Brně. Fakulta chemická, 2018. http://www.nusl.cz/ntk/nusl-376781.

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Degradace půdy zasolováním, zvyšující se teplota a následný úbytek mnonžství srážek v posledních letech vedou k rozšiřování aridních a semi-aridních oblastí (v současnosti pokrývají třetinu pevniny Země). Navíc představují globální environmentální problémy, které, pokud se nebudou správně řešit, můžou vést k vážné celosvětové krizi. V této diplomové práci jsme propojili tato témata a zaměřili se na lepší porozumění role sodných kationtů na vazbu vody v půdní organické hmotě v aridních a semi-aridních podmínkách. Náš cíl byl prozkoumat proces vzniku a stabilitu vodních molekulových můstků a vodních-kationických můstků v půdní organické hmotě, sílu vazby a množství vázáné vody v půdě za využití diferenční kompenzační kalorimetrie. Nasycení sodnými kationty bylo studováno ve dvou koncentračních oblastech. Na simulaci přirozených podmínek v půdách bylo použito nasycení vazebných míst sodnými kationty do 100% a nasycení nad 100% reprezentovalo vysoce zasolené půdy. Výsledky potvrdily význam schopnosti půdy získávat vodu ze vzdušné vlhkosti, podíl vody v půdě vzrůstal s relativní vlhkostí. Vyšší podíl vody v půdě pak způsoboval snížení síly vazebných interakcí, což bylo interpretováno jako fakt, že rovnováha mezi půdní a vzdušnou vlhkostí vede k optimální vlhkost půdy. Přítomnost sodných kationtů ve vzorcích do nasycení 100% měla na množství vody zanedbatelný vliv, ale v přesycených vzorcích umožňovala navázání většího množství vody. V přesycených vzorcích bylo také pozorováno zvýšení síly vazebných interakcí mezi půdou a vodou, což vede k její větší zádrži. Molekulové můstky byli stabilnější ve vzorcích, které obsahovaly Na+. Nejvyšší stabilita byla pozorována u 10% nasycených vzorcích, další zvyšování Na-saturace pak již vedlo k snižování stability molekulových můstků. Hlavním výstupem práce je, že tvorba vodních-kationických můstků stabilizuje půdní strukturu a že má vlyv na sílu a množství vody vázané v půdě, což představuje klíčové aspekty kvality půdy. Je potřebný rozsáhlejší výskum tohoto tématu, aby získané výsledky pomohli optimalizovat půdní manažment v aridních oblastech a také v ostatních oblastech, kde dochází k degradaci půdy.

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49

Lesoin, Sapho. "Migration cationique et anionique des métaux toxiques (Plomb, Chrome et Zinc) dans les sols sous l'effet d'un champ électrique." Phd thesis, Ecole Nationale des Ponts et Chaussées, 1997. http://tel.archives-ouvertes.fr/tel-00529773.

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Cette étude est une contribution à l'étude de la dépollution des sols à l'aide d'une modélisation expérimentale. L'objectif du travail est d'étudier les processus physico-chimiques intervenant au cours du transport de polluants métalliques toxiques dans les sols soumis à un champ électrique. Les essais sont réalisés en laboratoire avec des sols obtenus à partir d'un mélange d'un sable de Fontainebleau avec une solution cationique de polluant. Les polluants étudiés sont des métaux amphotères dont le plomb(II), le chrome(III) et le zinc(II), avec des concentrations initiales variant de 0,1 à 10 g/l. Une tension électrique constante est appliquée au dispositif pendant un temps déterminé. L'analyse des teneurs de polluant sur différents endroits de la cuve à l'arrêt du traitement dans le sol montre que la répartition du polluant varie en fonction de la nature et de la concentration initiale du polluant utilisé. Ainsi, dans le cas du plomb, nous avons observé trois cas de figure : - une distribution plutôt homogène du plomb dans la cuve pour une concentration initiale de 0,1 g de Pb2+/1, consécutive à un faible déplacement du polluant, - un appauvrissement des zones anodique et cathodique, par rapport à la teneur initiale, avec accumulation du polluant au centre de la cuve pour 1 g de Pb2+/1, - un appauvrissement important des zones anodiques avec accumulation du polluant à la cathode pour 10 g de Pb2+/1. Les mesures de pH réalisées sur le sol et sur l'eau interstitielle à différents intervalles de temps ont mis en évidence deux mécanismes à l'origine du transport du plomb : un transport cationique à l'anode en présence de pH acides, suivi d'un transport anionique à la cathode pour des pH basiques. En effet, certains hydroxydes métalliques peuvent, sous des conditions de pH basiques, former des anions par réactions de dissolution. Cette propriété permet alors de « remobiliser » le plomb précipité à la cathode sous forme d'anions plombates et de concentrer le polluant dans les zones centrales du dispositif. L'action combinée de ces deux mécanismes de transport concentre la pollution, soit au centre de la cuve, soit à la cathode suivant la concentration initiale. Selon les cas, l'action d'un champ électrique permettrait de restreindre le volume de sol pollué à traiter ultérieurement ou à excaver. La mesure de la conductivité électrique de l'eau interstitielle met en évidence des variations de la concentration ionique dans le milieu liées au déplacement du polluant ou à sa précipitation. Les concentrations utilisées dans le cas du chrome et du zinc ont mis en évidence un transport sous une forme cationique. Aucun phénomène de « remobilisation » n'a pu être observé car les pH mesurés à la cathode ne favorisaient pas un transport important du polluant sous forme d'anions.

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Dzene, Liva. "Influence de la taille des particules et de la cristallochimie sur les propriétés d'échange cationique des minéraux argileux gonflants." Thesis, Poitiers, 2016. http://www.theses.fr/2016POIT2283.

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Les minéraux argileux gonflants sont omniprésents dans tous les compartiments de la surface de la Terre et notamment dans les sols. La structure lamellaire de ces minéraux et leur faible taille leur confèrent une forte réactivité notamment vis à vis des polluants et nutriments qui sont présents dans les eaux porales des sols. Dans ce cadre, cette thèse vise à contribuer à une meilleure compréhension des interactions entre des minéraux argileux gonflants et des cations nutritifs (calcium, strontium) et/ou d'intérêt environnemental (césium). Dans les sols, ces minéraux possèdent de larges distributions de taille et de cristallochimie (charge des feuillets). Par conséquent, pour mieux comprendre le rôle de chacun de ces paramètres sur la réactivité de ces particules naturelles, nous avons travaillé avec des « systèmes modèles », représentatifs des particules argileuses des sols : des particules de vermiculite triées en taille et des saponites synthétiques avec des charges de feuillets contrôlées. Les résultats d'adsorption des cations étudiés (Cs, Sr) en compétition avec les cations majeurs des eaux naturelles (Na, Ca) ont été obtenus en couplant l'analyse chimique des solutions et la modélisation des réflexions 00ℓ des diffractogrammes de rayons X afin d'obtenir la distribution de cations entre les différents sites d'adsorption (interfoliaire vs externes). Une telle approche et l'utilisation des « systèmes modèles » nous ont permis d'obtenir des paramètres quantitatifs décrivant la réactivité des minéraux argileux gonflants des sols. Ces paramètres pourront être pris en compte dans les codes de transport prédisant la migration des cations dans les sols
The swelling clay minerals are ubiquitous in all areas of the surface of the Earth, particularly in soils. The lamellar structure of these minerals and their small size are at the origin of their high reactivity in particular with respect to pollutants and nutrients that are present in soil pore water. In this context, our work aims to contribute to a better understanding of the interactions between swelling clay minerals and cations of nutritive (calcium) and/or environmental interest (cesium, strontium). In soils, swelling clay minerals have broad size distribution and can have a varied crystal chemistry. Therefore, to better understand the role of each of these parameters on the reactivity of the natural particles, we worked with "model systems", which are yet representative of the swelling clay particles encountered in soil environment. Different particle size fractions of vermiculite and different synthetic saponites characterised by well-controlled layer charge were used as "model systems". Results concerning ion-exchange isotherms for Cs and Sr, in competition with major cations of natural waters (Na, Ca), were obtained by combining chemical analyses and 00ℓ reflection modelling of X-ray diffractograms in order to assess the cation distribution between the different adsorption sites (interlayer vs external) located on swelling clay minerals. Such approach and the use of ‘model systems’ have allowed us to obtain quantitative parameters describing the reactivity of soil swelling clay mineral particles, and should be considered in reactive transport codes devoted to predict the migration of nutritive and polluted cations in soil environments

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Dissertations / Theses on the topic 'Soils Cations'

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