No description available.

No description available.

This thesis considers methods which can be employed to increase the mass of copper transferred into and out of the organic phase during the load and strip stages of commercial solvent extraction processes. Conventional 5-alkylsalicylaldoxime reagents transfer 1 mol of divalent copper per 2 mol of ligand in a neutral complex of the type [Cu(L-H)2] via a pH-swing process. New triacidic ligands have been designed which triple the molar transport of copper to form [Cu3(L-3H)2]. Until recently copper recovery by solvent extraction has been confined to oxidic ores which are leached with sulfuric acid. New leaching technologies generate high tenor copper sulfate feed streams from sulfidic ores. The conventional 5- alkylsalicylaldoxime reagents do not work effectively in conjunction with these leach processes as they do not consume the acid which is generated on loading the oxime. To address this problem ditopic zwitterionic ligands have been designed which can transfer both metal cation and attendant anion. These new metal salt reagents are diacidic, therefore not only transfer metal salts but also increase the molar transport relative to the conventional reagents. Equilibrium-modifiers are often added to improve the mass transport efficiency of conventional solvent extraction processes. The nature of their interaction with the species in solution is poorly understood. This thesis investigates their interaction with the free ligands and copper complexes to gain an understanding of their mode of action in order to rationalise the design of future modifiers to optimise recovery efficiencies. Increased molar transport is addressed in Chapter 2. The diacidic ligand 5- methylsalicylaldehyde-pivaloylhydrazide (L2) and its dinuclear copper complex [Cu2(L2-2H)2] were synthesised and characterised to gain an understanding of their speciation in solution. X-ray structural analysis of [Cu2(L2-2H)2] confirmed that the phenolate oxygen atoms bridge the copper centres rather than the amidato oxygen atoms of the hydrazone. Variable temperature magnetic susceptibility data confirm that the copper centres are antiferromagnetically coupled as expected for the Cu-OCu angle (99.6(2)°). An understanding of the coordination geometry of the dinuclear systems lead to design of triacidic ligands. A series of 3-hydrazono- and 3- hydroxyanil- 5-alkylsalicylic acids were synthesised. The prototype ligand 5-methyl 3-octanoylhydrazonosalicylic acid (L6) was demonstrated to triple molar transport and increase mass transport by 2.5 fold. Solvent extraction results indicate that copper is sequentially loaded as pH is increased. The plateaux observed in loading curves suggest formation of stable mono-, di-, and tri-nuclear copper complexes within the pH-ranges 1.75 - 2.75, 3.25 - 4.0 and > 4.25 respectively. The triacidic ligands were also demonstrated to double the molar transport of the conventional salicylaldoximes when used in 1:1 blends by formation of a ternary complex. Chapter 3 describes the incorporation of two tertiary amine groups into diacidic salicylaldehydehydrazone ligands to form dinucleating metal salt extractants. Piperidinomethyl, piperazinomethyl and dihexylamino groups were incorporated into various positions of the ligand including 3- and/or 5- positions of the salicylaldehyde or incorporated into the hydrazone. Solvent extraction results obtained for 3,5- bis((dihexylamino)methyl)salicylaldehyde-octanoic hydrazone (L20) are consistent with transfer of 1 mol of copper sulfate per mol of ligand in the organic phase between pH 2.0 and 2.5. This result is indicative of the formation of [Cu2(L20)2(SO4)2]. Conventional salicylaldoximes are “strong” copper extractants which require concentrated acid electrolyte to efficiently strip the copper from the organic phase. However, as the use of concentrated acid affects the quality of the copper cathodes, oxygen-containing equilibrium modifiers are often added. These facilitate copper stripping without adversely affecting the loading. The affect of 2-ethylhexanol (2- EH) and trioctylphosphine oxide (TOPO) on the extractive ability of 5-toctylsalicylaldoxime (19) in n-heptane is reported. Both are found to decrease copper extraction more under stripping conditions than loading conditions. 2-EH shows little affect at pH greater than 2.5. TOPO does not significantly affect copper loading at pH greater than 3.0. Evidence for the formation of the adduct [Cu(19-H)2)(TOPO)] was obtained from UV/Vis, IR, EPR and sonic spray mass spectrometry.

No Brasil, tanto o agronegócio quanto a fabricação de celulose trazem resultados relevantes para a economia. Sob uma perspectiva de sustentabilidade, as indústrias beneficiadoras de materiais vegetais geram grande volume de resíduos, os quais podem servir de fonte de celulose, configurando-se numa alternativa atraente para gerar lucros e diminuir impactos ambientais negativos. O objetivo geral desta dissertação é realizar um estudo exploratório de extração de celulose a partir de resíduo do processo produtivo de empresa beneficiadora de material vegetal, sob perspectiva das dimensões ambiental e econômica da sustentabilidade. O estudo foi desdobrado em cinco etapas: i) identificação na literatura das diretrizes para os processos produtivos sustentáveis, por meio das abordagens que tratam da sustentabilidade; ii) identificação dos processos industriais de extração de celulose e suas características operacionais; iii) definição da empresa para realização do estudo, a sazonalidade e o volume disponível dos resíduos vegetais provenientes do processo de beneficiamento de vegetais; iv) adaptação do processo industrial de extração de celulose para uso com resíduos vegetais e atendimento às restrições da fábrica definida para o estudo e v) realização de testes de extração com o uso de projeto de experimentos para posterior caracterização da polpa de celulose obtida do resíduo. Neste último, foi empregado um Projeto Fatorial Composto de Segunda Ordem (PSCO) com Metodologia de Superfície Resposta (MSR) para analisar a influência dos fatores controláveis sobre as variáveis de resposta. Os fatores controláveis foram definidos de acordo com dados da literatura específica e foram analisadas as variáveis de resposta que caracterizam polpa de celulose, aplicáveis a fins sanitários, como Número Kappa, capacidade de absorção, velocidade de absorção e densidade. Resultados indicaram que limitações quanto ao uso de altas temperaturas no processo de extração é um fator relevante, para atingir maiores teores de deslignificação. Os estudos mostraram a influência do uso de aditivo de processo, antraquinona, carga alcalina e tempo de polpeamento, bem como, tratamento de hidrólise ácida no resíduo na qualidade da polpa. / Agribusiness and pulp production bring both relevant results to the Brazilian economy. In a sustainable perspective, the wastes of Industries that benefit vegetable materials may serve as pulp’s source, configuring itself as an attractive alternative for profit generation and reduction of negative environmental impacts. The aim in this dissertation is to carry out an exploratory study of pulp extraction from the waste of productive process of a firm which processes vegetal material, under the perspective of environmental and economic dimensions of sustainability. The study was unfolded in five steps: i) identification, in literature, the guidelines for sustainable productive processes, through approaches that embrace sustainability; ii) identification of industrial processes of pulp extraction and respective operational features; iii) definition of an industrial unit to perform the study, as well as the seasonality and the availability of vegetal wastes coming from the vegetable process; iv) adaptation of the industrial process of pulp extraction for using with vegetable wastes, and attendance to constraints of the current process in the industrial unit chosen for the study; and v) the performance of extraction tests using a project of experiments for further characterization of the cellulose pulp resulting from the waste. It was employed a Factorial composite second-order design in a Surface Response Methodology (SRM) in order to analyze the influence of the controlled variables over the response variables. Variables of the extraction process were defined according with the specific literature’s data, and response variables, adequate to the cellulose pulp characterization as Kappa Number, capability, absortion speed and apparent density were analyzed. Results indicate that constraints related to the high temperature used in the equipment available for extraction is a relevant factor in the process for obtaining higher contents of delignification. Studies show the influence of using additive process, anthraquinone, load time and alkaline pulping, as well as treatment of hydrolysis in the waste of pulp quality. The remarkable difference in the quality of vegetable waste after hydrolysis treatment indicates that a pretreatment stage of such waste is interesting, since the fiber is resistant and requires high alkali and addictive charges.

No Brasil, tanto o agronegócio quanto a fabricação de celulose trazem resultados relevantes para a economia. Sob uma perspectiva de sustentabilidade, as indústrias beneficiadoras de materiais vegetais geram grande volume de resíduos, os quais podem servir de fonte de celulose, configurando-se numa alternativa atraente para gerar lucros e diminuir impactos ambientais negativos. O objetivo geral desta dissertação é realizar um estudo exploratório de extração de celulose a partir de resíduo do processo produtivo de empresa beneficiadora de material vegetal, sob perspectiva das dimensões ambiental e econômica da sustentabilidade. O estudo foi desdobrado em cinco etapas: i) identificação na literatura das diretrizes para os processos produtivos sustentáveis, por meio das abordagens que tratam da sustentabilidade; ii) identificação dos processos industriais de extração de celulose e suas características operacionais; iii) definição da empresa para realização do estudo, a sazonalidade e o volume disponível dos resíduos vegetais provenientes do processo de beneficiamento de vegetais; iv) adaptação do processo industrial de extração de celulose para uso com resíduos vegetais e atendimento às restrições da fábrica definida para o estudo e v) realização de testes de extração com o uso de projeto de experimentos para posterior caracterização da polpa de celulose obtida do resíduo. Neste último, foi empregado um Projeto Fatorial Composto de Segunda Ordem (PSCO) com Metodologia de Superfície Resposta (MSR) para analisar a influência dos fatores controláveis sobre as variáveis de resposta. Os fatores controláveis foram definidos de acordo com dados da literatura específica e foram analisadas as variáveis de resposta que caracterizam polpa de celulose, aplicáveis a fins sanitários, como Número Kappa, capacidade de absorção, velocidade de absorção e densidade. Resultados indicaram que limitações quanto ao uso de altas temperaturas no processo de extração é um fator relevante, para atingir maiores teores de deslignificação. Os estudos mostraram a influência do uso de aditivo de processo, antraquinona, carga alcalina e tempo de polpeamento, bem como, tratamento de hidrólise ácida no resíduo na qualidade da polpa. / Agribusiness and pulp production bring both relevant results to the Brazilian economy. In a sustainable perspective, the wastes of Industries that benefit vegetable materials may serve as pulp’s source, configuring itself as an attractive alternative for profit generation and reduction of negative environmental impacts. The aim in this dissertation is to carry out an exploratory study of pulp extraction from the waste of productive process of a firm which processes vegetal material, under the perspective of environmental and economic dimensions of sustainability. The study was unfolded in five steps: i) identification, in literature, the guidelines for sustainable productive processes, through approaches that embrace sustainability; ii) identification of industrial processes of pulp extraction and respective operational features; iii) definition of an industrial unit to perform the study, as well as the seasonality and the availability of vegetal wastes coming from the vegetable process; iv) adaptation of the industrial process of pulp extraction for using with vegetable wastes, and attendance to constraints of the current process in the industrial unit chosen for the study; and v) the performance of extraction tests using a project of experiments for further characterization of the cellulose pulp resulting from the waste. It was employed a Factorial composite second-order design in a Surface Response Methodology (SRM) in order to analyze the influence of the controlled variables over the response variables. Variables of the extraction process were defined according with the specific literature’s data, and response variables, adequate to the cellulose pulp characterization as Kappa Number, capability, absortion speed and apparent density were analyzed. Results indicate that constraints related to the high temperature used in the equipment available for extraction is a relevant factor in the process for obtaining higher contents of delignification. Studies show the influence of using additive process, anthraquinone, load time and alkaline pulping, as well as treatment of hydrolysis in the waste of pulp quality. The remarkable difference in the quality of vegetable waste after hydrolysis treatment indicates that a pretreatment stage of such waste is interesting, since the fiber is resistant and requires high alkali and addictive charges.

No Brasil, tanto o agronegócio quanto a fabricação de celulose trazem resultados relevantes para a economia. Sob uma perspectiva de sustentabilidade, as indústrias beneficiadoras de materiais vegetais geram grande volume de resíduos, os quais podem servir de fonte de celulose, configurando-se numa alternativa atraente para gerar lucros e diminuir impactos ambientais negativos. O objetivo geral desta dissertação é realizar um estudo exploratório de extração de celulose a partir de resíduo do processo produtivo de empresa beneficiadora de material vegetal, sob perspectiva das dimensões ambiental e econômica da sustentabilidade. O estudo foi desdobrado em cinco etapas: i) identificação na literatura das diretrizes para os processos produtivos sustentáveis, por meio das abordagens que tratam da sustentabilidade; ii) identificação dos processos industriais de extração de celulose e suas características operacionais; iii) definição da empresa para realização do estudo, a sazonalidade e o volume disponível dos resíduos vegetais provenientes do processo de beneficiamento de vegetais; iv) adaptação do processo industrial de extração de celulose para uso com resíduos vegetais e atendimento às restrições da fábrica definida para o estudo e v) realização de testes de extração com o uso de projeto de experimentos para posterior caracterização da polpa de celulose obtida do resíduo. Neste último, foi empregado um Projeto Fatorial Composto de Segunda Ordem (PSCO) com Metodologia de Superfície Resposta (MSR) para analisar a influência dos fatores controláveis sobre as variáveis de resposta. Os fatores controláveis foram definidos de acordo com dados da literatura específica e foram analisadas as variáveis de resposta que caracterizam polpa de celulose, aplicáveis a fins sanitários, como Número Kappa, capacidade de absorção, velocidade de absorção e densidade. Resultados indicaram que limitações quanto ao uso de altas temperaturas no processo de extração é um fator relevante, para atingir maiores teores de deslignificação. Os estudos mostraram a influência do uso de aditivo de processo, antraquinona, carga alcalina e tempo de polpeamento, bem como, tratamento de hidrólise ácida no resíduo na qualidade da polpa. / Agribusiness and pulp production bring both relevant results to the Brazilian economy. In a sustainable perspective, the wastes of Industries that benefit vegetable materials may serve as pulp’s source, configuring itself as an attractive alternative for profit generation and reduction of negative environmental impacts. The aim in this dissertation is to carry out an exploratory study of pulp extraction from the waste of productive process of a firm which processes vegetal material, under the perspective of environmental and economic dimensions of sustainability. The study was unfolded in five steps: i) identification, in literature, the guidelines for sustainable productive processes, through approaches that embrace sustainability; ii) identification of industrial processes of pulp extraction and respective operational features; iii) definition of an industrial unit to perform the study, as well as the seasonality and the availability of vegetal wastes coming from the vegetable process; iv) adaptation of the industrial process of pulp extraction for using with vegetable wastes, and attendance to constraints of the current process in the industrial unit chosen for the study; and v) the performance of extraction tests using a project of experiments for further characterization of the cellulose pulp resulting from the waste. It was employed a Factorial composite second-order design in a Surface Response Methodology (SRM) in order to analyze the influence of the controlled variables over the response variables. Variables of the extraction process were defined according with the specific literature’s data, and response variables, adequate to the cellulose pulp characterization as Kappa Number, capability, absortion speed and apparent density were analyzed. Results indicate that constraints related to the high temperature used in the equipment available for extraction is a relevant factor in the process for obtaining higher contents of delignification. Studies show the influence of using additive process, anthraquinone, load time and alkaline pulping, as well as treatment of hydrolysis in the waste of pulp quality. The remarkable difference in the quality of vegetable waste after hydrolysis treatment indicates that a pretreatment stage of such waste is interesting, since the fiber is resistant and requires high alkali and addictive charges.

No description available.

No description available.

Notre étude s’inscrit dans un processus de recherche de nouveaux composés d’origine naturelle à activités biologiques avérées à partir de macroalgues brunes, avec d’éventuelles perspectives d’exploitation industrielle. Ainsi, dans un premier volet nous avons testé des méthodologies innovantes en matière d‘extraction en utilisant trois espèces d’algues brunes comme modèles. Nous avons optimisé le protocole d’extraction solide/liquide en estimant divers paramètres cruciaux qui influent sur le rendement d’extraction et sur les activités antiradicalaires des composés extraits. Soucieux de trouver une méthodologie innovante d’extraction plus « verte » répondant aux normes européennes, nous avons donc testé des méthodes d’extraction utilisant des solvants dans leur état supercritique ou sous forme pressurisés. La comparaison avec le procédé d’extraction solide/liquide nous a permis de sélectionner l’extraction par fluides pressurisés (PLE) employée avec un mélange Ethanol-Eau pour l’extraction de composés antiradicalaires avec une haute efficacité. Dans une deuxième partie nous nous sommes intéressés aux variations quantitatives et qualitatives des principales macromolécules présentes chez l’espèce invasive Sargassum muticum en Europe. L’emploi de deux techniques analytiques, RMN HR-MAS et spectroscopie IR, nous a permis d’avoir une vue d’ensemble des compartiments susceptibles de subir des variations selon la position géographique d’une même espèce à large répartition. Cette étude nous a montré comment une espèce est capable de changer sa composition biochimique en fonction de son environnement et ainsi s’acclimater à des milieux assez différents. Ce travail a mis en évidence les effets de différents paramètres environnementaux sur les compartiments lipidique (analysés en GC), protéique ainsi que sur les quantités de carbohydrates et de pigments (analysés en HPLC). L’influence de ces paramètres sur la taille des individus de Sargassum muticum a également été discutée. La dernière partie de cette étude nous a permis de décrire les variations quantitatives et qualitatives des phlorotannins chez l’espèce invasive Sargassum muticum sur une grande échelle spatiale, le long d’un gradient latitudinal (Norvège-Portugal). Dans un premier temps cette variabilité a été appréhendée grâce à un suivi temporel et spatial des teneurs en phlorotannins. L’étude des variabilités intra-spécifiques et intra-individuelles nous a permis de mettre en évidence un effet du stade de développement et de la partie de l’algue considérée : les teneurs et activités des phlorotannins sont plus importantes dans les crampons et chez les individus matures. Après la recherche d’un protocole simple pour la semi-purification des composés phénoliques présent chez Sargassum muticum, nous avons pu mettre en évidence la présence de composés de type phlorethol au moyen de techniques de RMN à deux dimensions (2D). Ces fractions semi-purifiées possèdent des activités antiradicalaire et antibactérienne notoires. Enfin, l’utilisation de plusieurs techniques de séparation membranaires nous a permis d’estimer le poids moléculaire des différents composés présents dans le pool de composés phénoliques extrait. Enfin, suite aux constats effectués sur les populations, l’effet de l’intensité lumineuse et de la température de l’eau a pu être apprécié isolément : les radiations UVA et UVB boostent la production de CP alors qu’une augmentation de la température fait chuter la production de CP chez S. muticum. / Our study is part of the research process for new compounds of natural origin with biological activities and possible industrial perspectives. In a first part, we tested innovative extraction methodologies using three brown algae species as model. We optimized the solid/liquid extraction protocol by estimating diverse crucial parameters which influence the extraction yield and radical scavenging activities of extracts. In order to find an innovative and more "green" extraction methodology answering the European standards, we thus tested more recent extraction methods using solvents in their supercritical state or under pressure. The comparison with the solid/liquid process allowed us to select pressurized liquid extraction (PLE) using an ethanol-water mixture for the extraction of active compounds with a high efficiency, but also to select Sargassum muticum as an interesting model for further investigations. In a second part, we were interested in the quantitative and qualitative variations of the main macromolecules present in the invasive species S. muticum in Europe. The employment of two analytical techniques (NMR HR-MAS and IR spectroscopy), allowed us to have an overview of biochemical parts of the algae, which vary according to the geographical position of this wide spread species. This study showed how a species is able to modify its biochemical composition, and then to acclimate, according to the environment. We then focused on molecules, which showed important variations along the latitudinal range of S. muticum. This work highlighted the effects of environmental parameters on lipid (GC analysis) and protein compartments as well as on carbohydrates and pigments quantities (HPLC analysis). The influence of these parameters on the size of individuals was also discussed. The last part of this study allowed us to describe the quantitative and qualitative variations of phlorotannins in S. muticum on a large spatial scale, along a latitudinal gradient (Norway-Portugal). At first this variability was measured thanks to temporal and spatial follow-up of the phlorotannins contents. The study of intra-specific and intra-individual variabilities allowed us to highlight an effect of the development stage and of the seaweed part: phlorotannins contents and activities are more important in holdfast and in mature individuals. After the research of a simple protocol for the phenolic compounds semi-purification present in Sargassum muticum, we were able to highlight the presence of compounds of only phlorethol type in this species by means of 2D RMN techniques. These semi-purified fractions possess notorious radical scavenging and antibacterial activities. Finally, the use of several membrane separation techniques allowed us to consider the molecular weight of the various compounds present in the extracted pool of phenolic compounds. Finally, under controlled conditions, the effects of the light quality and the seawater temperature were tested: UV-A and UV-B radiations boost the production of CP while an increase of the temperature makes the phlorotannins production decreasing in S. muticum.