Preliminary results of research focused on the applications of DC diaphragm discharge in water solutions containing humic substances are presented in this diploma thesis. Electrical discharges in water produce various reactive species such as radicals (•OH, •O, •H), ions and molecules (H2O2, O3). These species have high oxidation potential and thus they easily react with order species and molecules. Such reactions could lead, for example, to destruction of organic pollutants dissolved in water. This work studies this effect on humic matters that can be contained in water coming from floods. Diaphragm discharge investigated by this work was created in the reactor using konstant DC high voltage up to 2 kV that gave the total input power from 100 to 200 W. Breakdown and discharge ignition started in the pin-hole in the dielectric barrier separating two electrode spaces (anode and cathode space). Presented work investigates decomposition of humic substances by the electric discharge in the dependence of solution properties and discharge conditions. Parameters such as initial solution conductivity, electrolyte kind or input power have been investigated. Moreover, substantial effect of pH on humic acid decomposition has been observed. Refraktometry and absorption spectroscopy in UV-VIS region together with fluorescence spectroscopy has been used for the detection of changes in humic solutions.

Submitted by Angela Maria de Oliveira (amolivei@uepg.br) on 2018-06-05T14:40:04Z No. of bitstreams: 2 license_rdf: 811 bytes, checksum: e39d27027a6cc9cb039ad269a5db8e34 (MD5) Schardosin, Janaina.pdf: 3840457 bytes, checksum: ffe3148238384650d2997e09aff27ed0 (MD5) / Made available in DSpace on 2018-06-05T14:40:04Z (GMT). No. of bitstreams: 2 license_rdf: 811 bytes, checksum: e39d27027a6cc9cb039ad269a5db8e34 (MD5) Schardosin, Janaina.pdf: 3840457 bytes, checksum: ffe3148238384650d2997e09aff27ed0 (MD5) Previous issue date: 2018-04-09 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / O processo de humificação, conversão de resíduos orgânicos em húmus, é um fator importante na compreensão da dinâmica da matéria orgânica. A sua quantificação, é fundamental para o estudo da evolução química dessa substância. O objetivo deste trabalho foi caracterizar as amostras de ácidos húmicos (AHs) e quantificar o grau de humificação do solo e das frações físicas (por tamanho de partículas). As análises de Espectroscopias de Fluorescência de Raios X por Dispersão de Comprimento de Onda, Fluorescência na região do Visível, Espectroscopia Vibracional na região de Infravermelho e de Absorção na região do Ultravioleta e Vísivel, Espectrocospia Raman, acompanhadas das técnicas de Análise Térmica, Microscopia Eletrônica de Varredura com Canhão Eletrônico por Efeito de Campo e Espalhamento Dinâmico da Luz foram utilizadas. A quantificação do grau de humificação mostrou que AHs extraídos da profundidade (10- 20 cm) possuem estruturas aromáticas mais condensadas. A fração de AH que apresentou maior grau de humificação foi a extraída do solo com a adição de calagem, o que demonstra uma influência do calcário na aceleração do processo de humificação. O estudo das frações granulométricas do solo, determinou, com espectroscopia de infravermelho, os atributos orgânicos que estão associados as frações do solo e, que a maioria dos minerais presentes nas frações granulométricas, foram identificados como sendo caulinita, haloisita, quartzo e gibbsita. Já para o estudo da humificação dos AHs extraídos das frações granulométricas, a quantificação do grau de humificação, do maior para o menor, é procedente da fração silte, seguidos da fração argila e, por fim, a fração areia. / The humification process, conversion of organic waste into humus, is an important factor to understand the organic matter dynamics. Its quantification is vital for the study of this substance chemical evolution. This study aimed at characterizing humic acid (HA) samples and quantify the degree of soil humification and physical fractions (particle size). The analysis of Spectroscopies of wavelenght dispersive X-ray fluorescence, visible fluorescence, vibrational infrared region, ultraviolet and visible light absorption and Raman along with the techniques of Thermal Analysis, scanning electron microscopy with field effect gun and dynamic light scattering were employed. The humification degree quantification revealed that the HA extracted from the 10-20cm depth presented more polycondensed structures. The HA fraction that presented the highest humification degree was extracted from the soil with the addition of liming, which demonstrates the limestone influence in the acceleration of the humification process. The study of the soil granulometric fractions determined, with infrared spectroscopy, the organic properties that are associated to soil fractions and that most of the minerals present in the granulometric fractions, were identified as kaolinite, halloysite, quartz and gibbsite.The study of the humification in the HA extracted from the granulometric fractions quantified the humification degree and revealed the highest values in the silt fraction followed by the clay fraction and, finally, the lowest values were found in the sand fraction.

L'application des bois raméaux fragmentés (BRF) dans les pratiques agricoles constitue une technique durable de restauration de la fertilité des sols. Et pourtant, la lignine qui lui confère majoritairement la capacité de formation de l'humus et de stabilisation du carbone organique du sol n'a pas encore fait objet d'une étude scientifique approfondie. L'objectif général de cette thèse de doctorat est de caractériser les lignines organosolv isolées des BRF de Gmelina arborea et Sarcocephalus latifolius et d'évaluer l'effet des amendements de ces BRF sur les propriétés physico-chimiques et la diversité fongique du sol ainsi que le rendement des cultures maraichères (tomate et gombo) sur deux sites agricoles au Bénin. Les objectifs spécifiques sont : (i) de déterminer les constituants et les propriétés chimiques du bois et des BRF des essences G. arborea et S. latifolius à partir des méthodes de chimie du bois; (ii) d'isoler et caractériser les lignines organosolv de ces essences par le procédé catalytique et suivre son devenir dans les sols sur deux sites au Bénin après deux ans ; (iii) d'évaluer les effets des amendements des sols avec les BRF sur le stock du carbone, la formation des substances humiques stables et la diversité fongique du sol; et (iv) d'évaluer les effets des amendements des sols avec les BRF sur les propriétés physico-chimiques et hydriques du sol ainsi que sur la production de la tomate et du gombo sur deux sites au Bénin. L'essence Gmelina arborea a été retenue pour le site de Sékou, et celle de Sarcocephalus latifolius pour celui de Kika. Les bois de tronc et BRF ont été caractérisés pour leur composition élément³¹aire et en lignines. La moitié des BRF était enfouie dans le sol, et l'autre moitié était utilisée comme paillis. L'effet des traitements a été évalué sur la production de la tomate et du gombo. Les BRF ont été échantillonnés après 0, 6, 12 et 18 mois d'incubation dans le sol afin d'isoler et caractériser leur lignine organosolv par des analyses spectroscopiques (FTIR, ³¹P RMN, 2D HSQC) et pyrolytique (Py-GC-MS-TMAH). Les résultats ont montré que les lignines organosolv des BRF des deux essences étaient de types guaiacyl-syringyl (G-S). Les analyses chimiques des BRF ont montré que la teneur en glucides totaux diminuait, tandis que la teneur en lignine totale augmentait au fur et à mesure de la décomposition des BRF dans le sol. Un enrichissement significatif en azote (N) des BRF a été déterminé après 18 mois d'incubation dans les sols, atteignant 2,6 et 1,9 fois la teneur initiale en N pour G. arborea et S. latifolius, respectivement. En outre, les BRF ont amélioré l'humidité volumique du sol, régulé la température du sol et diminué la tension hydrique du sol par rapport aux LV et témoins sur 24 mois. Par ailleurs, les traitements à base des BRF (BRF et BRF_LV) ont contribué de manière significative au stockage du carbone organique du sol et à l'augmentation des nutriments du sol (N, P, K, Ca, Mg) (cette dernière jusqu'à 1,5 fois) par rapport au témoin. Les résultats d'analyse de l'acide humique (HA) extrait des sols, purifié et analysé ont révélé que les sols amendés avec le BRF ont produit des quantités significatives d'HA constitués majoritairement des composés dérivés de lignine. En outre, en utilisant le séquençage de la région ITS2 sur la plateforme Illumina Miseq, l'application des BRF a considérablement modifié la composition fongique avec une augmentation de l'abondance relative des Ascomycota (jusqu'à 92% de la communauté fongique totale), Mucoromycota, Basidiomycota et Rozellomycota. Les résultats ont montré que l'amendement au BRF a réduit significativement le rendement de la tomate (sauf sur le site de Kika) et du gombo pendant la première production de culture et que l'amélioration de la croissance et du rendement de ces légumes a été significative qu'à partir de la deuxième production de culture. Cette recherche démontre ainsi le rôle positif des BRF à travers leur lignine à former de l'humus stable et à favoriser une production agricole durable. / Application of RCW in agriculture is a sustainable technique for restoring soil fertility. However, the lignin from the RCW, which contributes to the formation of humus and to the soil organic carbon storage, has not yet been thoroughly studied. The general objective of this PhD thesis is to characterize the organosolv lignins isolated from RCWs of G. arborea and S. latifolius and to evaluate the effect of RCW amendments on the physico-chemical properties and fungal diversity of the soil as well as on the yield of vegetable crops (tomato and okra) on two agricultural sites in Benin. The specific objectives are: (i) to determine the constituents and chemical properties of trunk wood and RCW of G. arborea and S. latifolius using wood chemistry methods; (ii) to isolate and characterize the organosolv lignins of these species by the catalytic process and to follow its fate in soils on two sites in Benin after two years; (iii) to evaluate the effects of soil amendments with RCWs on carbon stock, formation of stable humic substances and soil fungal diversity; and (iv) to evaluate the effects of soil amendments with RCWs on soil physicochemical and hydric properties as well as on tomato and okra production on two sites in Benin. The G. arborea species was selected for the Sékou site, and S. latifolius for the Kika site. The trunk wood and RCW were characterized for their elemental and lignin composition. Half of the RCWs was incorporated in the soil, while the other half was put as mulch. The effect of the treatments was evaluated on tomato and okra production. RCWs were sampled after 0, 6, 12 and 18 months of incubation in the soil to isolate and characterize their organosolv lignins by spectroscopic (FTIR, 31P NMR, 2D HSQC) and chromatographic (Py-GC-MS-TMAH) analyses. The results showed that the organosolv lignins from RCWs of both species were of guaiacyl-syringyl (G-S) types. Chemical analyses of the RCWs showed that total carbohydrate content decreased, while total lignin content increased as RCWs decomposed in the soils. Significant nitrogen (N) enrichment of RCWs was determined after 18 months of incubation in soils, reaching 2.6 and 1.9 times the initial N content for G. arborea and S. latifolius. In addition, RCWs improved soil water content, regulated soil temperature, and decreased soil hydric tension compared to PL treated soils and controls over 24 months. Furthermore, RCW treatments (RCW and RCW_PL) contributed significantly to soil organic carbon storage and increased soil nutrients (N, P, K, Ca, Mg) (the latter up to 1.5 times) compared to the control. The humic acid (HA) was extracted from soils, purified, and analyzed by NMR spectroscopic and Py-GC-MS chromatography. The obtained results revealed that soils amended with RCWs produced significant amounts of HA containing a significant amount of lignin-related structures. Furthermore, using ITS2 region sequencing on the Illumina Miseq platform, RCW application significantly altered the fungal composition with an increase in the relative abundance of Ascomycota (up to 92% of the total fungal community), Mucoromycota, Basidiomycota and Rozellomycota. The obtained results showed that RCW amendment significantly reduced the yield of tomato (except at Kika site) and okra during the first crop production and that the improvement in growth and yield of these vegetables was significant only from the second crop production. This research thus demonstrates the positive role of RCWs through their lignin in forming stable humus and promoting sustainable agricultural production.

Eine biochemische Indikation des Anteils exogener organischer Kohlenstoffquellen (EOC), der nach dem Eintrag potenziell im Boden verbleibt (Cpot) wurde entwickelt. Haupthypothese dieser Studie war, dass der Abbau von EOC durch die biochemische Zusammensetzung vorhergesagt werden kann, welche bei Pflanzenrückständen von der Kulturart, dem Pflanzenrückstandstyp sowie dem Anbausystem und im Allgemeinen vom Ausgangssubstrat organischer Düngestoffe und der EOC-Kategorie (pyrogen , mikrobiell und pflanzlich) beeinflusst wird. Zunächst wurden Pflanzenrückstände im Energiepflanzenanbau zur Biogasgewinnung (Restpflanze / Stroh, Stoppeln, Grobwurzeln, Feinwurzeln, natürlicher Bestandsabfall) von Mais, Sorghum, Sudangras, Wintergetreide, Hafer, Erbse in Einzel-, Zwei- und Mischkultursystemen betrachtet. In einem zweiten Schritt wurden Pflanzenrückstände im Allgemeinen mit organischen Düngern, Komposten, Rückständen aus anaerober Vergärung in der Biogasproduktion (Gärrückstände) und Biokohlen verglichen. Die biochemische Zusammensetzung von EOC wurde durch die Konzentrationen von Kohlenstoff- (C), Stickstoff (N), wasserlöslicher Kohlehydrate (WSC), Hemizellulose (HEM), Zellulose (CEL) und Lignin (LIC) in g pro kg Trockenmasse dargestellt. In Inkubationsversuchen wurde EOC gleichmäßig mit Boden vermischt und über 310 Tage die Zugabe-induzierte Kohlendioxid-Freisetzung gemessen. Cpot wurde als Grenzwert der Modellschätzung für die Inkubationsdaten bestimmt. Die Beziehung zwischen biochemischer Zusammensetzung und Cpot wurde durch die Partial-Least-Squares-Regression-Methode abgeleitet. Cpot unterschied sich stärker zwischen verschiedenen organischen Düngestoffen, als speziell zwischen verschiedenen Pflanzenrückständen und konnte durch die biochemische Zusammensetzung vorhergesagt werden. Der Indikator für Cpot (in g C pro kg EOC) wurde als Ipot = 269 + 13 N – 0.5 WSC + 0.7 CEL + 1.5 LIC für Pflanzenrückstände und im Allgemeinen als Ipot = 924 – 1.9 C + 2.0 LIC vorgeschlagen. / A biochemical indication for the fraction of exogenous organic carbon (EOC), potentially remaining in soil after application (Cpot) has been developed. Main hypothesis of this study was that decomposition of EOC can be predicted by the biochemical composition, which in case of plant residues is influenced by the crop residue type, crop species and agricultural management and in general depends on the original substrate and category (pyrogen, microbial, and plant-derived EOC) of organic materials. A first set of EOC was created, containing plant residues in energy crop cultivation for biogas production (shoot / straw, stubble, coarse root, fine root, and litter) of maize, sorghum, sudan grass, winter cereal, pea, and oats in single-, double- and intercropping systems. In a second set of EOC, plant residues in general were compared with other organic fertilisers, urban composts, residues of anaerobic fermentation in biogas production (digestates), and biochar. The biochemical composition of EOC was characterised by the concentrations of carbon (C), nitrogen (N), water-soluble carbohydrates (WSC), hemicelluloses (HEM), cellulose (CEL), and lignin (LIC) in g per kg dry matter. In incubation experiments, EOC was homogeneously incorporated into soil and EOC-induced carbon dioxide-release was measured for 310 d. Cpot was determined as modelled limit for the incubation results. Finally, the relation between biochemical composition and Cpot of EOC was evaluated by the partial least squares regression method. Cpot largely varied between different types and categories of EOC, while less variation was obtained between different plant residues. The biochemical composition was predictive for Cpot (expressed as g C per kg EOC), proposing the biochemical indicator as Ipot = 269 + 13 N – 0.5 WSC + 0.7 CEL + 1.5 LIC specifically for plant residues and as Ipot = 924 – 1.9 C + 2.0 LIC for EOC in general.