O gênero Acacia apresenta espécies florestais de rápido crescimento, com rotações curtas (7 a 9 anos) e de grande interesse comercial para produção de polpa celulósica, painéis de madeira e energia. No Brasil a utilização de espécies do gênero Acacia na produção de celulose de fibra curta ainda é bastante restrita e são poucos os estudos que demonstram a potencialidade do uso dessa matéria-prima para a obtenção de polpa celulósica com as propriedades alcançadas pelas espécies do gênero Eucalyptus. Este trabalho teve como objetivo analisar o potencial de algumas espécies do gênero Acacia (A.aulacocarpa, A. auriculiformis, A. crassicarpa, A. mangium) plantados no Brasil, para a produção de polpa celulósica Kraft, considerando os aspectos relacionados à qualidade da madeira e da polpa, o consumo de reagentes químicos na polpação e também os aspectos relacionados ao rendimento e a capacidade de produção de polpa celulósica; adicionalmente buscou-se fornecer informações estratégicas para o setor celulósico nacional com relação as possíveis ameaças e as oportunidades apresentadas pelos materiais não utilizados no Brasil. Para realização deste trabalho foram utilizados 11 materiais genéticos distintos e cada um dos materiais genéticos foi considerado um tratamento e todos com 5 anos de idade. As características avaliadas foram: densidade básica, dimensões das fibras, composição química e parâmetros da polpação kraft (rendimento bruto, rendimento depurado, teor de rejeitos, número kappa e relações). Para este último objetivo, as madeiras de cada uma das espécies foram submetidas ao processo de polpação kraft, considerando-se seis níveis de álcali ativo: 18,0; 19,5; 21,0; 22,5; 24,0 e 25,5%, mantendo-se constantes as outras variáveis de cozimento. Observou-se que o modelo de variação longitudinal para densidade básica da árvore mantém uma tendência dos valores serem mais elevados na base e valores mínimos entre 25 e 50% da altura comercial. Quanto à composição química os valores foram distintos para todas as espécies e apresentaram uma variação de 60,99% para A. auriculiformis (1) e 68,79% para A. aulacocarpa (1) como valores mínimo e máximo. Os resultados obtidos quanto às dimensões das fibras não apresentaram padrões definidos de variação entre as espécies. Notou-se quanto aos parâmetros da polpação um efeito diferenciado entre as espécies de Acacia para as distintas cargas de álcali ativo. Considerando a curva de polpação para obtenção de número kappa 18 entre as espécies estudadas, obteve-se como média para a demanda carga de alcalina 23,8% e a média do rendimento depurado nestas condições foi 54,72%. A espécie A. crassicarpa procedência (1) destacou-se por apresentar a maior conversão em massa (ton/ha) de madeira na produção de celulose e a A. mangium procedências (1, 2, 3 e principalmente 4) alcançaram os melhores resultados de rendimento frente ao processo kraft de polpação comparando toas as espécies deste estudo. / The genus Acacia includes fast-growing short-rotation (7 to 9 years) forest tree species of commercial interest to produce pulp, wood panels, and energy. In Brazil, the utilization of species of the genus Acacia to produce short fiber pulp is still highly restricted and few studies are available that demonstrate the potential use of this raw material to obtain pulp presenting the properties displayed by species of the genus Eucalyptus. This study aimed at analyzing the potential of some species of the genus Acacia (A. aulacocarpa, A. auriculiformis, A. crassicarpa, A. mangium) planted in Brazil to produce kraft pulp, considering the aspects related to wood and pulp quality, consumption of chemical reagents during the pulping process, yield, and cellulose pulp production capacity. Furthermore, this work searched for strategical information for the national pulp and paper sector as to possible threats and opportunities presented by materials not used in Brazil in order to provide knowledge and discuss the potential competitiveness of these types of wood in the world market for pulp and paper. To accomplish these goals, we used 11 5-year-old distinct genetic materials, each one of them considered a different treatment. The following traits were evaluated: basic density, longitudinal variation, fiber dimensions, chemical composition, and kraft pulping process parameters (total yield, screened yield, rejects content, kappa number and relations). To carry out these evaluations, each wood species underwent the kraft pulping process considering six levels of active alkalis: 18.0, 19.5, 21.0, 22.5, 24.0, and 25.5%, keeping all other cooking variables constant. We observed that the model of longitudinal variation in the basic density maintains the trend of reaching higher values in the base of the tree and minimum values between 25% and 50% of the commercial height. The values found for the chemical composition were different for all the species studied and the holocellulose content ranged from a minimum of 60.99% found for A. auriculiformis (1) to a maximum of 68.79% found for A. aulacocarpa (1). The results obtained for fiber dimensions did not present defined patterns of variation among the species. The kraft pulping process parameters showed differences among Acacia species for the distinct levels of active alkalis. Considering the pulping process curve to get the kappa number of 18 among the species studied, the average alkali demand was 23.8% and the average depurated yield under these conditions was 54.72%. A. crassicarpa procedure 1 presented the highest conversion into wood mass (t/ha) to produce cellulose and A. mangium procedures (1, 2, 3, and mainly 4) reached the best results in terms of yield when they underwent the kraft pulping process compared to all the species studied herein.

Der elektrochemische Nachweis von polycyclischen aromatischen Kohlenwasserstoffen (PAK), zu denen Anthracen und Pyren gehören, bietet eine kostengünstigere, einfachere und schnellere alternative Analysemethode als herkömmliche Methoden wie GC und HPLC. Im Vergleich zu diesen Methoden weist er jedoch nach wie vor eine geringere Empfindlichkeit auf. Einige neuere Bemühungen haben an einem Mangel an Selektivität gelitten, entweder aufgrund der elektrodenmodifizierende Schicht mit hohem Hintergrundstrom oder der Wahl eines Leitelektrolyten, der die Detektion stört. Bei dem vorliegenden Versuch wurden Pt-Pd-Nanopartikel (NPs) und MWCNTs verwendet, um eine Glaskohlenstoffelektrode (GCE) zum empfindlichen Nachweis von Anthracen und Pyren zu modifizieren. Die verwendeten NPs wurden unter Verwendung eines wässrigen Extrakts aus Blättern von E. grandis synthetisiert, einem nachhaltigen und umweltfreundlichen Syntheseweg. Durch einer Optimierung der Mengen an Pt- und Pd-Ionen im Vorläufer wurden NPs mit einer durchschnittlichen Größe von 10 nm erhalten, wobei ein Verhältnis von 1 Pt-Ion zu 3 Pd-Ionen die kleinste Größe ergab. Durch XPS wurde festgestellt, dass die Zusammensetzung der NPs von Pt2+ und Pd0 dominiert wird. Die XRD-Analyse ergab eine kristalline Natur mit einer flächenzentriert-kubischen Struktur. Die Pt-Pd-NPs bewirkten eine Erhöhung des Spitzenstroms um 94 % für Pyren, führten jedoch zu niedrigeren Spitzenströmen für Anthracen. Wenn die NPs weiter mit MWCNTs zum Nachweis von Pyren verwendet wurden, wurde eine Spitzenstromsteigerung von etwa 200 % mit einem Dynamikbereich von 66–130 μM und einer LOD von 23 μM beobachtet. Es wurde auch festgestellt, dass der elektrochemische Prozess gemischt diffusions- und adsorptionskontrolliert ist. Aufgrund des Einflusses der Adsorption musste die Akkumulationszeit im Analyseverfahren berücksichtigt werden. MWCNTs wurden beim Nachweis von Anthracen angewendet, wobei eine Erhöhung des Spitzenstroms um 74 % und eine Verringerung des Überpotentials um 53 mV beobachtet wurde. Ein dynamischer Bereich von 50–146 µM und eine LOD von 42 µM wurden bestimmt. Niedrigere Konzentrationen wurden mit einer Leitungswasserprobe gemessen, die mit Anthracen versetzt war, hauptsächlich wegen der geringen Löslichkeit von PAK in Wasser. Der Einfluss der Säurebehandlung von MWCNTs auf den Nachweis von Anthracen und Pyren wurde ebenfalls untersucht. Die Säurebehandlung ermöglichte das Laden von mehr Material ohne Ablösen der modifizierten Schicht, was zu höheren Spitzenstromverbesserungen für Anthracen (533 %) und Pyren (448 %) führte. Für Anthracen und Pyren wurden LODs von 40 µM bzw. 14 µM bestimmt, die nur geringfügig niedriger sind als die bei MWCNTs/GCE und Pt-PdNPs/MWCNTs/GCE beobachteten Werte. Der Nachweis von Anthracen wurde durch die Anwesenheit von Pyren und gewöhnlichen Ionen gestört, während die LOD für Pyren in Gegenwart von Anthracen 18 µM betrug. Es wurde festgestellt, dass die auf MWCNTs basierende elektrochemische Nachweisplattform eine bessere Reaktion auf Pyren aufweist.:Bibliographische Beschreibung i Referat i Abstract iii Zeitraum, Ort der Durchführung v Acknowledgements vi Dedication vii Table of Contents viii List of Abbreviations and Symbols xii Chapter 1 1 Introduction 1 1.1 Overview 1 1.2 Polycyclic Aromatic Hydrocarbons 2 1.3 Electrochemical Sensors 7 1.3.1 General Response Curve for Chemical Sensors 10 1.4 Carbon Nanotubes 13 1.5 Use of Nanoparticles in Electrochemical Detection 18 1.6 Green Synthesis of Nanoparticles and The Rationale Behind It 21 1.7 Previous Efforts in the Electrochemical Detection of Polycyclic Aromatic Hydrocarbons 24 1.8 Objectives of the Study 26 Chapter 2 28 Experimental 28 2.1 Chemicals 28 2.1.1 Preparation of Anthracene and Pyrene Solutions 28 2.2 Collection and Preparation of Plant Material 29 2.3 Synthesis and Preparation of Materials 29 2.3.1 Synthesis of Metallic Nanoparticles 29 2.3.2 Acid Treatment of Multi-walled Carbon Nanotubes 30 2.4 Characterization of the Nanomaterials 30 2.4.1 UV-Vis Spectrophotometry 30 2.4.2 SEM/EDX and TEM Analysis 30 2.4.3 Powder X-ray Diffractometry 31 2.4.4 XPS Analysis 31 2.5 Electrochemical Measurements 31 2.5.1 Preparation of the Bare and Modified Glassy Carbon Electrode 32 2.5.2 Characterization of the Bare and the Modified Glassy Carbon Electrode 33 2.5.3 Electrocatalytic Oxidation of Anthracene on the Bare and Modified GCEs 33 2.5.4 Electrocatalytic Oxidation of Pyrene on the Bare and Modified GCEs 34 Chapter 3 35 Synthesis, Characterization, and Application of Pt-Pd Nanoparticles in the Electrochemical Detection of Anthracene and Pyrene 35 3.1 Test for Flavonoids and Polyphenols in the E. grandis Leaves’ Extract 35 3.2 Synthesis of Nanoparticles 35 3.3 Characterization of Nanoparticles 37 3.3.1 TEM Analysis 37 3.3.2 SEM Analysis 40 3.3.3 EDX Analysis 41 3.3.4 Powder X-Ray Diffraction Analysis 45 3.3.5 XPS Analysis of Pt-Pd Particles 46 3.4 Impedance Measurements of the Bare and Nanoparticle-modified Glassy Carbon Electrode 49 3.5 Electrochemical Oxidation of Anthracene and Pyrene at the Bare and Nanoparticles-modified Glassy Carbon Electrode 51 3.6 Conclusions 53 Chapter 4 55 Pt-PdNPs/MWCNTs-Modified GCE for the Detection of Pyrene 55 4.1 Impedance Measurement with Pt-PdNPs/MWCNTs/GCE 55 4.2 Electrochemical Oxidation of Pyrene on Pt-PdNPs/MWCNTs/GCE 56 4.3 Analysis of Varying Concentrations of Pyrene on Pt-PdNPs/MWCNTs/GCE 59 4.4 Selectivity 61 4.5 Conclusions 62 Chapter 5 64 Exploring Multi-walled Carbon Nanotubes for the Detection of Anthracene 64 5.1 Impedance Measurement of MWCNT-Modified Glassy Carbon Electrode 64 5.2 Electrochemical Oxidation of Anthracene on MWCNT/GCE 65 5.3 Analysis of Varying Concentrations of Anthracene Using MWCNTs/GCE 68 5.4 Detection of Anthracene in Tap Water 71 5.5 Conclusions 72 Chapter 6 73 Effect of Acid Treatment of Multi-walled Carbon Nanotubes on the Detection of Anthracene and Pyrene 73 6.1 Characterization of fMWCNTs 74 6.2 Electrochemical Oxidation of Anthracene on fMWCNTs/GCE 75 6.2.1 Effect of Change in Scan Rate 76 6.2.2 Effect of Accumulation Time 77 6.2.3 Application of fMWCNTs/GCE in the Analysis of Varying Concentrations of Anthracene 77 6.3 Electrochemical Oxidation of Pyrene on fMWCNTs/GCE 79 6.4 Selectivity 82 6.4.1 Co-detection of Anthracene and Pyrene at fMWCNTs/GCE 83 6.4.2 Interference of Some Common Ions 85 6.5 Detection of Pyrene in Tapwater using fMWCNTs/GCE 86 6.6 Conclusions 87 Chapter 7 88 Summary and Outlook 88 7.1 Summary 88 7.2 Outlook 90 References 92 Selbständigkeitserklärung 101 Curriculum Vitae 102 / Electrochemical detection of polycyclic aromatic hydrocarbons (PAHs), which include anthracene and pyrene, offers a cheaper, simpler, and faster alternative method of analysis than conventional methods like GC and HPLC. However, it still is not as sensitive as these methods. Some recent efforts have suffered from lack of selectivity, either from the electrode modifying layer having high background current or from the choice of supporting electrolyte interfering with the detection. In this work, Pt-Pd nanoparticles (NPs) and MWCNTs were used to modify a glassy carbon electrode (GCE) for sensitive detection of anthracene and pyrene. The NPs used were synthesized using an aqueous extract from E. grandis leaves, a sustainable and environmentally friendly synthetic route. NPs with an average size of 10 nm were obtained by optimizing the amounts of Pt- and Pd-ions in the precursor, with a ratio of 1:3 Pt to Pd-ions producing the smallest size. Through XPS, the composition of the NPs was established to be dominated by Pt2+ and Pd0. XRD analysis revealed a crystalline nature with a face-centered cubic structure. The Pt-Pd NPs produced 94 % enhancement in the peak current for pyrene but resulted in lower peak currents for anthracene. When the NPs were further used with MWCNTs for the detection of pyrene, about 200% peak current enhancement was observed with a dynamic range of 66–130 µM and LOD of 23 µM. The electrochemical process was also established to be mixed diffusion- and adsorption-controlled. The influence of adsorption necessitated the employment of accumulation time in the analysis procedure. MWCNTs were applied in the detection of anthracene and a 74 % peak current enhancement and a reduction in the overpotential by 53 mV were observed. A dynamic range of 50–146 µM and LOD of 42 µM were determined. Lower concentrations were recovered from a tap water sample that was spiked with anthracene, mainly because of the low solubility of PAHs in water. Effect of acid treatment of MWCNTs on the detection of anthracene and pyrene was also investigated. Acid treatment allowed for loading of more material without peeling off of the modified layer which resulted in higher peak current enhancements for anthracene (533%) and pyrene (448%). LODs of 40 µM and 14 µM were determined for anthracene and pyrene respectively, which are only slightly lower than what was observed at MWCNTs/GCE and Pt-PdNPs/MWCNTs/GCE. Detection of anthracene was interfered by the presence of pyrene and common ions, while the LOD for pyrene in the presence of anthracene was 18 µM. The MWCNTs based electrochemical detection platform was found to have a better response towards pyrene.:Bibliographische Beschreibung i Referat i Abstract iii Zeitraum, Ort der Durchführung v Acknowledgements vi Dedication vii Table of Contents viii List of Abbreviations and Symbols xii Chapter 1 1 Introduction 1 1.1 Overview 1 1.2 Polycyclic Aromatic Hydrocarbons 2 1.3 Electrochemical Sensors 7 1.3.1 General Response Curve for Chemical Sensors 10 1.4 Carbon Nanotubes 13 1.5 Use of Nanoparticles in Electrochemical Detection 18 1.6 Green Synthesis of Nanoparticles and The Rationale Behind It 21 1.7 Previous Efforts in the Electrochemical Detection of Polycyclic Aromatic Hydrocarbons 24 1.8 Objectives of the Study 26 Chapter 2 28 Experimental 28 2.1 Chemicals 28 2.1.1 Preparation of Anthracene and Pyrene Solutions 28 2.2 Collection and Preparation of Plant Material 29 2.3 Synthesis and Preparation of Materials 29 2.3.1 Synthesis of Metallic Nanoparticles 29 2.3.2 Acid Treatment of Multi-walled Carbon Nanotubes 30 2.4 Characterization of the Nanomaterials 30 2.4.1 UV-Vis Spectrophotometry 30 2.4.2 SEM/EDX and TEM Analysis 30 2.4.3 Powder X-ray Diffractometry 31 2.4.4 XPS Analysis 31 2.5 Electrochemical Measurements 31 2.5.1 Preparation of the Bare and Modified Glassy Carbon Electrode 32 2.5.2 Characterization of the Bare and the Modified Glassy Carbon Electrode 33 2.5.3 Electrocatalytic Oxidation of Anthracene on the Bare and Modified GCEs 33 2.5.4 Electrocatalytic Oxidation of Pyrene on the Bare and Modified GCEs 34 Chapter 3 35 Synthesis, Characterization, and Application of Pt-Pd Nanoparticles in the Electrochemical Detection of Anthracene and Pyrene 35 3.1 Test for Flavonoids and Polyphenols in the E. grandis Leaves’ Extract 35 3.2 Synthesis of Nanoparticles 35 3.3 Characterization of Nanoparticles 37 3.3.1 TEM Analysis 37 3.3.2 SEM Analysis 40 3.3.3 EDX Analysis 41 3.3.4 Powder X-Ray Diffraction Analysis 45 3.3.5 XPS Analysis of Pt-Pd Particles 46 3.4 Impedance Measurements of the Bare and Nanoparticle-modified Glassy Carbon Electrode 49 3.5 Electrochemical Oxidation of Anthracene and Pyrene at the Bare and Nanoparticles-modified Glassy Carbon Electrode 51 3.6 Conclusions 53 Chapter 4 55 Pt-PdNPs/MWCNTs-Modified GCE for the Detection of Pyrene 55 4.1 Impedance Measurement with Pt-PdNPs/MWCNTs/GCE 55 4.2 Electrochemical Oxidation of Pyrene on Pt-PdNPs/MWCNTs/GCE 56 4.3 Analysis of Varying Concentrations of Pyrene on Pt-PdNPs/MWCNTs/GCE 59 4.4 Selectivity 61 4.5 Conclusions 62 Chapter 5 64 Exploring Multi-walled Carbon Nanotubes for the Detection of Anthracene 64 5.1 Impedance Measurement of MWCNT-Modified Glassy Carbon Electrode 64 5.2 Electrochemical Oxidation of Anthracene on MWCNT/GCE 65 5.3 Analysis of Varying Concentrations of Anthracene Using MWCNTs/GCE 68 5.4 Detection of Anthracene in Tap Water 71 5.5 Conclusions 72 Chapter 6 73 Effect of Acid Treatment of Multi-walled Carbon Nanotubes on the Detection of Anthracene and Pyrene 73 6.1 Characterization of fMWCNTs 74 6.2 Electrochemical Oxidation of Anthracene on fMWCNTs/GCE 75 6.2.1 Effect of Change in Scan Rate 76 6.2.2 Effect of Accumulation Time 77 6.2.3 Application of fMWCNTs/GCE in the Analysis of Varying Concentrations of Anthracene 77 6.3 Electrochemical Oxidation of Pyrene on fMWCNTs/GCE 79 6.4 Selectivity 82 6.4.1 Co-detection of Anthracene and Pyrene at fMWCNTs/GCE 83 6.4.2 Interference of Some Common Ions 85 6.5 Detection of Pyrene in Tapwater using fMWCNTs/GCE 86 6.6 Conclusions 87 Chapter 7 88 Summary and Outlook 88 7.1 Summary 88 7.2 Outlook 90 References 92 Selbständigkeitserklärung 101 Curriculum Vitae 102

O aumento do consumo da madeira e de seus produtos, como os painéis de madeira, estimula o desenvolvimento de tecnologia de produtos que utilizam os insumos caracterizados como resíduos. Neste aspecto, o país reúne vantagens competitivas, pela extensa área de plantações de eucalipto de alta produtividade, detém a primeira posição na produção de cana-de-açúcar e possui um parque industrial com avançada tecnologia de produção de painéis de fibras e de partículas. Com este contexto, o presente trabalho teve como principal objetivo a confecção e a caracterização tecnológica de painéis de fibras de madeira de eucalipto, Eucalyptus grandis e de partículas do bagaço do colmo de cana-de-açúcar, Saccharum sp. Os ensaios laboratoriais compreenderam, inicialmente, a caracterização macroscópica das matérias primas e suas misturas, bem como classificação granulométrica do bagaço de cana-de-açúcar. Em seguida, foram estabelecidas 2 etapas referentes ao processo de confecção dos painéis, denominadas etapa A (0-100% de bagaço de cana-de-açúcar, com variações de 25%; 14% de resina UF) e etapa B (0-25% de bagaço de cana-de-açúcar, com variações de 5%; 13 e 16% de resina UF). A caracterização tecnológica dos painéis compreendeu a análise da sua morfologia (microscopia MEV, microtomografia de raios X/microCT), densitometria de raios X, propriedades físicas (densidade, inchamento, absorção e umidade), mecânicas (MOR, MOE, resistências à trações perpendicular e superficial, arrancamento de parafuso); análises óticas por deflectometria, química (espectroscopia NIR, teor de formol livre e sílica) e durabilidade natural (bioensaios de fungos xilófagos e cupins). Os resultados da avaliação morfológica indicaram diferenças da estrutura anatômica das matérias primas e de granulometria das partículas de bagaço de cana-de-açúcar. A avaliação morfológica dos painéis evidenciou, através da microCT, a homogeneidade da matriz fibrosa, cuja composição anatômica foi diferenciada através do MEV. Na caracterização das propriedades físico-mecânicas, os perfis de densidade aparente dos painéis, típicos de painéis de fibras, indicaram a influência da matéria prima e sua mistura. Ainda, verificou-se uma redução das propriedades mecânicas, notadamente MOR, MOE e resistência á tração perpendicular, dos painéis confeccionados com mais de 50% de partículas do bagaço de cana-de-açúcar; quanto à resina, 16% resultou em melhor desempenho tecnológico em relação à 13%. Os valores de MOE dos painéis foram similares aos obtidos pela aplicação da técnica ótica de deflectometria. O aumento percentual de partículas do bagaço de cana-de-açúcar nos painéis resultou em redução do teor de formol livre e no aumento do teor de sílica. A aplicação da metodologia NIR permitiu a diferenciação das fibras da madeira de eucalipto e das partículas de bagaço de cana-de-açúcar e seus percentuais praticados. Nos bioensaios os painéis (etapa B) não apresentaram diferenças significativas quanto à resistência ao ataque de fungos e cupins. Os resultados permitem concluir que os painéis de fibras de eucalipto e partículas de bagaço de cana-de-açúcar, como matéria prima alternativa e em percentuais entre 5-25%, apresentaram propriedades tecnológicas que atendem às normas, indicando o potencial da utilização desta biomassa para produtos de maior valor agregado. / The increased consumption of wood and its products, such as wood panels, stimulates the development of technology for products that use inputs characterized as waste. In this respect, Brazil has competitive advantages regarding the large area of high-yield eucalyptus crops; Brazil is the worlds major sugarcane producer and has an industrial sector with advanced technology for fiberboards and particleboards production. Therefore, this study aimed to develop the manufacture and technological characterization of wood fibers from eucalyptus, Eucalyptus grandis, and stalk particles of sugarcane bagasse, Saccharum sp. Laboratory analyses included, initially, the macroscopic characterization of raw materials and their mixtures as well as sorting granules of crushed sugarcane bagasse. Then, two steps were established for the panel-making process, called phase A (0-100% of sugarcane bagasse, with variations of 25%, 14% UF resin) and phase B (0 - 25% of sugarcane bagasse, with variations of 5%, 13 and 16% UF resin). The technological characterization of the panels comprised the morphology analysis (SEM microscopy, X-ray microtomography / microCT), X-ray densitometry, physical properties (density, swelling in thickness, absorption and moisture content), mechanical (MOR, MOE, internal bond, surface resistance and axial withdrawal of screw); optical analysis by deflectometry, chemical (NIR spectroscopy, free formaldehyde content of sand content) and natural durability (bioassays of fungi and termites). The results indicated morphological differences of anatomical structure of raw materials and particle size of sugarcane bagasse. The morphological evaluation of the panels showed, through the microCT, the homogeneity of the fibrous matrix, whose anatomical composition was different through SEM. In the characterization of physical-mechanical properties, the density profiles of the panels, typical of fiberboards, indicated the influence of raw materials and their mixture. Still, there was a reduction of mechanical properties, notably MOR, MOE and internal bond to the panels made with more than 50% of sugarcane bagasse particles; regarding the resin, 16% resulted in better technological performance compared to 13%. The MOE values of the panels were similar to those obtained by applying the deflectometry technique. The percentage of sugarcane bagasse particles in the panels resulted in reduction of the level of free formaldehyde and increase of the sand content. The use of the NIR methodology allowed the differentiation of eucalyptus wood fibers and particles of sugarcane and their percentage applied. In bioassays, the panels (step B) showed no significant differences in resistance to fungi and termites. The results indicate that the panels of eucalyptus fibers and particles of sugarcane bagasse, as an alternative raw material and at percentages between 5-25% showed technological properties that meet the standards, indicating the potential use of this biomass for products with higher value added.

Thesis (MScFor)--Stellenbosch University, 2014. / ENGLISH ABSTRACT: A field trial of six replications was established to test the effect of various wood ash and fertilisers application rates on soil chemistry, tree nutrition and early growth rate of a clonal Eucalyptus grandis x urophylla stand. Wood ash from pulpmills is currently disposed of in landfills. Increasing costs and potential environmental risks have driven companies to investigate alternative disposal methods. Ash consists of a combination of carbonates, hydroxides and other calcium containing minerals that induce the liming effect if ash is applied to a soil. The trial was established near Richards Bay in October 2013 on a sandy soil with a low buffer capacity and a pH of approximately 5.5. The trial consists of four wood ash application rates in combination with three levels of fertiliser, viz. no fertiliser, 150 g conventional NPK fertiliser mixture, or 320g NPK controlled release mixture. Fertiliser mixtures and application levels were based on previous fertiliser trials in the region. Ash application rates for the field trial were based on a lab incubation study done with soil samples from Richards Bay, to which increasing amounts of lime were added. The study tested wood ash application rates of 0, 300, 600 and 1200 kg/ha. Field measurements were taken at 4 and 8 months after trial establishment. The primary objective was to investigate which application levels in combination with the type of fertiliser could be applied to soils without negatively affecting the stand nutrition or increase the levels of potentially harmful elements in the soil; thus investigating the feasibility of safely disposing wood ash on plantation soils as an alternative disposal method. Soil nutrient concentrations were not affected by individual wood ash treatments, but more a product of the time interval after the ash additions were made. Soil C, P, K+ and Mg2+ showed decreased concentrations from 4-8 months after establishment. Ca2+ concentrations increased in the same time interval. In addition, Na+ and B concentrations decreased from 4-8 months. Soil heavy metal concentrations for Cd, Hg, Cr and Pb, analysed for 0-1200 kg/ha ash rates, were well below toxic levels at both time intervals. Wood ash induced a temporary liming effect. Mean soil pH increased with 0.6 units for the period 0 - 4 months and decreased with 0.4 units at 4 - 8 months after trial establishment. Foliar nutrient analyses and assessment techniques revealed sub-optimal nutrient concentrations for P, K and Zn at 4 and 8 months of age. Concentrations were defined as sub-optimal, as none of the nutrients were below critical levels. Foliar heavy metal concentrations for Cd, Hg, Cr and Pb, measured at both time intervals, were less than 1mg/kg. The small concentrations found in this project were attributed to the low bioavailability of all four elements and were likely a product of the edaphic factors at Richards Bay, which was representative of a large greater portion of the Zululand coastal plain sites. The response in biomass index ranged between 13 % and 683 % relative to the control treatment (A0F0). Results showed that application of purely wood ash, or in combination with a supplementary N and P source increased growth up to 8 months after trial establishment for wood ash applications up to 1200 kg/ha. This project demonstrated that 1200 kg/ha wood ash can safely be disposed of on a typical Zululand coastal sand with little environmental risk and no supressed growth, provided that it is balanced with an appropriate NP fertiliser. / AFRIKAANSE OPSOMMING: ‘n Veldproef met ses herhalings is in Oktober 2013 uitgelê met die doel om die uitwerking van verskillende vlakke hout as en kunsmis toedienings op die grond-voedingstof status, boom-voedingstof status en die groei-tempo van ‘n Eucalyptus grandis x urophylla hibried plantasie te bestudeer. Hout as by pulpmeulens word tans weggegooi op stortingsterreine. Toenemende onkostes vir storting en die omgewingsrisiko’s gebonde aan stortingsterreine, dryf maatskappye om verbeterde en meer omgewingsvriendelike metodes te ondersoek om van die as ontslae te raak. Hout as bestaan uit ‘n reeks karbonate, hidroksiede en kalsium bevattende minerale en is verantwoordelik vir die bekalkingseffek op die grond na toediening. Die veldproef is geleë naby Richardsbaai op ‘n sanderige grond met n lae bufferkapasiteit en pH van ongeveer 5.5. Die proef het vier hout as vlakke getoets, gekombineer met drie vlakke van bemesting: geen, 150g konvensionele landbou kunsmis (CV) óf 320g beheerd-vrystellende kunmis (CRF). Die kunsmismengsels en vlakke van bemesting is gebaseer op bestaande of voltooide bemestingseksperimente in die streek. Hout as vlakke was bereken in gekontroleerde laboratorium toestande en gebaseer op ‘n inkubasie studie met grond monsters verkry vanaf Richardsbaai, waarby toenemende vlakke suiwer landboukalk gevoeg is. Die veldproef het hout as vlakke van 0, 300, 600 en 1200 kg/ha getoets. Veld metings is op 4 en 8 maande na behandeling geneem. Die primêre doelwit van die studie was om te bepaal watter vlak hout as en kunmis kombinasie toegedien kan word, sonder om die grond-voedingstof status negatief te beïnvloed of ‘n potensiële skadelike uitwerking op die plantasie groei te veroorsaak. Die uiteinde van die studie was om die haalbaarheid van hout as toedienings op plantasie gronde te bestudeer relatief tot die huidige praktyk van storting, insluitend die risiko van moontlike skadelike newe-effekte. Grondvoedingstatus was nie beduidend beïnvloed deur individuele hout as toevoegings nie, maar was eerder ‘n funksie van die tydsduur sedert behandeling. Grond koolstof, P anione, K+ en Mg2+ konsentrasies het beduidend afgeneem in die periode van 4 - 8 maande na behandling. Die Ca2+ konsentrasies het toegeneem tussen 4 en 8 maande en terselfdertyd het Na+ en B konsentrasies afgeneem. Die swaarmetaal status, spesifiek vir Cd, Hg, Cr en Pb, vir toevoegings van 0-1200 kg/ha hout as was beduidend laer as toelaatbare vlakke in gronde op albei tydsintervalle. Die hout as het ‘n tydelike toename in grond pH veroorsaak. Die gemiddelde pH het tussen 0 - 4 maande toegeneem met 0.6 eenhede en gedurende 4 - 8 maande afgeem met 0.4 eenhede. Blaarontledings en voedingstof assesseringsmetodes het sub-optimale konsentrasies vir P, K en Zn getoon op die ouderdom van 4 en 8 maande. Voedingstof konsentrasies is as sub-optimaal geklassifiseer, omdat konsentrasies nooit laer as kritieke waardes vir gebreksimptome was nie. Die inhoud van Cd, Hg, Cr en Pb in blare was aansienlik kleiner as 1 mg/kg op albei tydsintervalle. Die merkwaardige lae konsentrasies wat in die projek aangeteken is, word toegekryf aan die lae bio-beskikbaarheid van al vier elemente as gevolg van die edafiese faktore eie aan die Richardsbaai omgewing (en ook aan groot dele van die Zoeloelandse kusvlakte). Die groeireaksie (bepaal as biomassa indeks op ouderdom 8 maande) het gewissel van 13 % - 683 % groter as die kontrole behandeling (A0F0). Resultate het bewys dat toedienings van suiwer hout as, of hout as gekombineer met ‘n addisionele N en P kunsmisbron die groei postief beïnvloed tot op die ouderdom van 8 maande. Die studie het bewys dat 1200 kg/ha hout as veilig toegedien kan word op die sandgronde van die kusgebiede in Zululand, met minimale omgewingsrisiko en geen tekens onderdrukte groei nie, mits dit gebalanseer word met ‘n geskikte NP kunsmisbron.

O aumento do consumo da madeira e de seus produtos, como os painéis de madeira, estimula o desenvolvimento de tecnologia de produtos que utilizam os insumos caracterizados como resíduos. Neste aspecto, o país reúne vantagens competitivas, pela extensa área de plantações de eucalipto de alta produtividade, detém a primeira posição na produção de cana-de-açúcar e possui um parque industrial com avançada tecnologia de produção de painéis de fibras e de partículas. Com este contexto, o presente trabalho teve como principal objetivo a confecção e a caracterização tecnológica de painéis de fibras de madeira de eucalipto, Eucalyptus grandis e de partículas do bagaço do colmo de cana-de-açúcar, Saccharum sp. Os ensaios laboratoriais compreenderam, inicialmente, a caracterização macroscópica das matérias primas e suas misturas, bem como classificação granulométrica do bagaço de cana-de-açúcar. Em seguida, foram estabelecidas 2 etapas referentes ao processo de confecção dos painéis, denominadas etapa A (0-100% de bagaço de cana-de-açúcar, com variações de 25%; 14% de resina UF) e etapa B (0-25% de bagaço de cana-de-açúcar, com variações de 5%; 13 e 16% de resina UF). A caracterização tecnológica dos painéis compreendeu a análise da sua morfologia (microscopia MEV, microtomografia de raios X/microCT), densitometria de raios X, propriedades físicas (densidade, inchamento, absorção e umidade), mecânicas (MOR, MOE, resistências à trações perpendicular e superficial, arrancamento de parafuso); análises óticas por deflectometria, química (espectroscopia NIR, teor de formol livre e sílica) e durabilidade natural (bioensaios de fungos xilófagos e cupins). Os resultados da avaliação morfológica indicaram diferenças da estrutura anatômica das matérias primas e de granulometria das partículas de bagaço de cana-de-açúcar. A avaliação morfológica dos painéis evidenciou, através da microCT, a homogeneidade da matriz fibrosa, cuja composição anatômica foi diferenciada através do MEV. Na caracterização das propriedades físico-mecânicas, os perfis de densidade aparente dos painéis, típicos de painéis de fibras, indicaram a influência da matéria prima e sua mistura. Ainda, verificou-se uma redução das propriedades mecânicas, notadamente MOR, MOE e resistência á tração perpendicular, dos painéis confeccionados com mais de 50% de partículas do bagaço de cana-de-açúcar; quanto à resina, 16% resultou em melhor desempenho tecnológico em relação à 13%. Os valores de MOE dos painéis foram similares aos obtidos pela aplicação da técnica ótica de deflectometria. O aumento percentual de partículas do bagaço de cana-de-açúcar nos painéis resultou em redução do teor de formol livre e no aumento do teor de sílica. A aplicação da metodologia NIR permitiu a diferenciação das fibras da madeira de eucalipto e das partículas de bagaço de cana-de-açúcar e seus percentuais praticados. Nos bioensaios os painéis (etapa B) não apresentaram diferenças significativas quanto à resistência ao ataque de fungos e cupins. Os resultados permitem concluir que os painéis de fibras de eucalipto e partículas de bagaço de cana-de-açúcar, como matéria prima alternativa e em percentuais entre 5-25%, apresentaram propriedades tecnológicas que atendem às normas, indicando o potencial da utilização desta biomassa para produtos de maior valor agregado. / The increased consumption of wood and its products, such as wood panels, stimulates the development of technology for products that use inputs characterized as waste. In this respect, Brazil has competitive advantages regarding the large area of high-yield eucalyptus crops; Brazil is the worlds major sugarcane producer and has an industrial sector with advanced technology for fiberboards and particleboards production. Therefore, this study aimed to develop the manufacture and technological characterization of wood fibers from eucalyptus, Eucalyptus grandis, and stalk particles of sugarcane bagasse, Saccharum sp. Laboratory analyses included, initially, the macroscopic characterization of raw materials and their mixtures as well as sorting granules of crushed sugarcane bagasse. Then, two steps were established for the panel-making process, called phase A (0-100% of sugarcane bagasse, with variations of 25%, 14% UF resin) and phase B (0 - 25% of sugarcane bagasse, with variations of 5%, 13 and 16% UF resin). The technological characterization of the panels comprised the morphology analysis (SEM microscopy, X-ray microtomography / microCT), X-ray densitometry, physical properties (density, swelling in thickness, absorption and moisture content), mechanical (MOR, MOE, internal bond, surface resistance and axial withdrawal of screw); optical analysis by deflectometry, chemical (NIR spectroscopy, free formaldehyde content of sand content) and natural durability (bioassays of fungi and termites). The results indicated morphological differences of anatomical structure of raw materials and particle size of sugarcane bagasse. The morphological evaluation of the panels showed, through the microCT, the homogeneity of the fibrous matrix, whose anatomical composition was different through SEM. In the characterization of physical-mechanical properties, the density profiles of the panels, typical of fiberboards, indicated the influence of raw materials and their mixture. Still, there was a reduction of mechanical properties, notably MOR, MOE and internal bond to the panels made with more than 50% of sugarcane bagasse particles; regarding the resin, 16% resulted in better technological performance compared to 13%. The MOE values of the panels were similar to those obtained by applying the deflectometry technique. The percentage of sugarcane bagasse particles in the panels resulted in reduction of the level of free formaldehyde and increase of the sand content. The use of the NIR methodology allowed the differentiation of eucalyptus wood fibers and particles of sugarcane and their percentage applied. In bioassays, the panels (step B) showed no significant differences in resistance to fungi and termites. The results indicate that the panels of eucalyptus fibers and particles of sugarcane bagasse, as an alternative raw material and at percentages between 5-25% showed technological properties that meet the standards, indicating the potential use of this biomass for products with higher value added.