A problemática envolvendo os efluentes têxteis decorre principalmente da elevada coloração que apresentam, devido à presença de corantes que além de serem quimicamente estáveis, podem ser tóxicos e/ou carcinogênicos. Logo, quando são descartados in natura no meio ambiente causam problemas estéticos e, sobretudo, ambientais mesmo em baixas concentrações, além da possibilidade de serem nocivos à saúde humana e dos animais. Neste contexto, o objetivo deste trabalho foi estudar a degradação eletroquímica de dois corantes têxteis, Reativo Azul 19 (RA-19) e o Reativo Preto 5 (RP-5) via Oxidação Anódica (OA), utilizando ânodos de Diamante Dopado com Boro (DDB) suportados em titânio ou em nióbio, via processo Eletro-Fenton (EF) e pela combinação dos processos com H2O2 eletrogerado e OA (CP), usando um eletrodo de Carbono Vítreo Reticulado (CVR) como cátodo. As degradações foram realizadas em célula eletroquímica de um compartimento e em reator de fluxo do tipo filtro-prensa com dois compartimentos. A eficiência das degradações foi monitorada pelas técnicas de espectrofotometria no UV-VIS, Cromatografia Líquida de Alta Eficiência (CLAE) e análise do teor de Carbono Orgânico Total (COT). As variáveis estudadas foram densidade de corrente (10-100 mA cm-2 em célula e 4-41 mA cm-2 em reator), dopagem do eletrodo de DDB/Ti (5.000 e 15.000 ppm B/C), concentração inicial dos íons Fe2+ (0-0,10 mmol L-1) e dos corantes (10-250 mg L-1). As degradações dos corantes apresentaram uma cinética de pseudo ordem zero; exceto quando o corante RP-5 foi degradado pelo processo EF, sendo o melhor ajuste ao modelo de pseudo primeira ordem. Além disso, em iguais condições eletroquímicas o corante RP-5 foi degradado em menor tempo em relação ao RA-19; sendo que em todos os processos estudados os corantes foram totalmente removidos. Considerando a OA em célula com os eletrodos de DDB/Ti, a degradação foi positivamente influenciada pelo aumento da densidade de corrente e dopagem do eletrodo, especialmente em relação a cinética. Além disso, os corantes RA-19 e RP-5 foram completamente removidos em 35 e 50 min de eletrólise quando 100 mA cm-2 foi aplicada ao eletrodo de DDB/Ti dopado com 15.000 ppm relação B/C. Em 2 h, 37% em mineralização foi observado para ambos os corantes e a toxicidade do RA-19 diminuiu contra as bactérias Vibrio fischeri. Ainda nessa condição total mineralização foi alcançada após 8 h de degradação. A remoção de COT foi favorecida utilizando o reator contendo os eletrodos de DDB/Nb e CVR ao invés da célula eletroquímica, chegando a percentuais de 84 e 82% em 30 e 90 min para os corantes RA-19 e RP-5 que foram removidos em 7,5 e 5 min, respectivamente, quando a densidade de 41 mA cm-2 foi aplicada ao DDB/Nb durante a degradação via exclusivamente OA. Entre os processos realizados no reator, o EF foi o energeticamente mais favorável, promovendo remoção em COT de 60 e 74% para os corantes RA-19 e RP-5 com consumo energético de 204 e 208 kWh kg-1, além disso, a completa remoção dos corantes ocorreu em 15 e 7,5 min, respectivamente, quando o eletrólito continha íons Fe2+ na concentração de 0,10 mmol L-1 e aplicando-se -0,4 V vs Ag/AgCl ao eletrodo de CVR. Na degradação os corantes via CP o RA-19 e RP-5 foram completamente removidos em 30 e 15 min com mineralização de 72 e 82% em 90 min associada a consumos energéticos de 562 e 745 kWh kg-1, respectivamente, quando 41 mA cm-2 foi aplicada ao DDB/Nb. Por fim, concluiu-se que os resultados das degradações dos corantes foram promissores, já que rápida remoção dos corantes foi observada, além da parcial mineralização. Logo os processos propostos podem ser aplicados na remoção dos corantes em água; sendo necessários realizar mais estudos, principalmente em relação ao material eletródico e configuração do sistema eletroquímico visando a aplicação industrial. / The main problem involving the textile wastewater is theirs high coloration since they present dyes, which are chemically stable and can be toxic and/or carcinogenic. Therefore, when the textile wastewater are discarded in nature in the environment, even in low concentrations, they may cause not only aesthetic and environmental problems, but also can be harmful to human and animal health. In this context, the aim of the study was to evaluate the electrochemical degradation of two textile dyes, Reactive Blue 19 (RB-19) and Black 5 (RB-5) via Anodic Oxidation (AO) using as anodes Boron Doped Diamond electrodes (BDD) supported on titanium or niobium, via Electro-Fenton (EF) process and by combination of processes with electrogenerated H2O2 and AO (CP) using a Reticulated Vitreous Carbon electrode (RVC) as cathode. The degradations assays were carried out in an electrochemical cell with one compartment and in a filter-press flow reactor with two compartments. The efficiency of degradation was monitored by UV-VIS spectrophotometry, High Performance Liquid Chromatography (HPLC) and analysis of Total Organic Carbon (TOC). The variables studied were current density (10-100 mA cm-2 for cell and 4-41 mA cm-2 for reactor), doping of the BDD/Ti electrodes (5,000 e 15,000 ppm B/C), initial concentration of the Fe2+ ions (0-0,10 mmol L-1) and dyes (10-250 mg L-1). The kinetic results showed that the removal of dyes followed the model of pseudo zero order; except when the RB-5 dye was degraded by EF process, which the best fitted was to pseudo first order model. Furthermore, for equal conditions the RB-5 was degraded in less time in comparison to the RB-19. In addition, the dyes were fully removed in all the processes studied. Regarding the AO in cell with BDD/Ti, the degradation was positively influenced by the increasing in current density and doping of the electrode, primarily the kinetics parameters. In addition, total removal of RB-19 and RB-5 was achieved in 35 and 50 min of electrolysis when 100 mA cm-2 was applied to the electrode doped with 15,000 ppm ratio B/C. In 2 h, 37% in mineralization was attained for both dyes and the toxicity effect of the RB-19 decreased against the bacteria Vibrio fischeri. In this condition, total TOC removed was also reached after 8 h. The TOC removal was enhanced using the reactor fitted with BDD/Nb and RVC instead of the electrochemical cell, achieving TOC removal of 84 and 82% in 30 and 90 min for RB-19 and RB-5 which were removed in 7.5 and 5 min, respectively, when 41 mA cm-2 was applied to the BDD/Nb in the degradation exclusively via AO. Among the processes carried out in the reactor, the EF was the energetically most favourable since TOC removal of 60 and 74% for RB-19 and RB-5 with energy consumption of 204 and 208 kWh kg-1 were noted. In addition, the RB-19 and RB-5 were completely removed in 15 and 7.5 min, respectively, when the electrolyte containing 0.10 mmol L-1 of Fe2+ ions and -0.4 V vs Ag/AgCl was applied to CVR electrode. The combination of processes with electrogenerated H2O2 and AO for degradation of the dyes removed the RB-19 and RB-5 in 30 and 15 min with mineralization of 71.6 and 81.8% in 90 min associated to energy consumptions of 562 and 745 kWh kg-1 respectively, when 41 mA cm-2 was applied to BDD/Nb. Therefore, the degradation results of the dyes were promised since quickly removal of the dyes and partial mineralization were observed hence the proposed processes could be used to remove the dyes from water. However, more studies are needed to enable an industrial application, especially regarding the electrode material and configuration of the electrochemical system.

Mit Lösungen von 9,10-Diphenylanthracen und N(C2H5)4ClO4 oder N(C4H9)4ClO4 als Leitsalz im Lösungsmittel Acetonitril wurden Elektrochemilumineszenz (ECL)-Experimente durchgeführt. Dazu wurden die Elektroden mit Folgen von jeweils drei in bestimmten zeitlichen Abständen aufeinander folgenden Potentialsprüngen polarisiert. Es wird gezeigt, dass bei entsprechender Wahl der Potentiale und der Haltezeiten anodische und kathodische ECL-Emissionen gleicher Intensität erzeugt werden können. Sodann wurde ECL in den Derivaten von Poly(p-phenylen-vinylen), MEH-PPV und DB-PPV erzeugt. Diese leitfähigen Polymere wurden als dünne Schichten auf Platin-Elektroden aufgebracht und wie bei ECL aus der Lösungsphase in Acetonitril-Elektrolyten mit Tetralkylammonium-Leitsalzen Potentialsprüngen unterworfen. Bei geeigneter Einstellung der Potentialsprünge und Haltezeiten konnten anodische und kathodische ECL gleicher Intensität erhalten werden. Dies ist das erste Mal, dass symmetrische ECL mit polymerbeschichteten Elektroden erhalten wurde. Die Kinetik der ECL weicht deutlich von der aus der Lösungsphase ab. Der ECL-Prozess verläuft langsamer als in der Lösungsphase, und der Leitelektrolyt hat einen signifikanten Einfluss auf das elektrochemische Verhalten der Polymerschicht. Die Ursachen dafür wurden über Modellrechnungen analysiert, mit denen die Ladungstransportprozesse in der Polymerschicht simuliert wurden. In derartigen Simulationsrechnungen konnten die Geschwindigkeitskonstanten der ECL-Reaktion sowohl im Polymer als auch in der Lösung bestimmt werden. Um die Stabilität der Polymerschichten zu erhöhen, wurde versucht, die Polymerketten mit Synchrotronstrahlung zu vernetzen. Diese Experimente brachten nicht das erwartete Ergebnis. Die Ursachen dafür werden auf der Grundlage von Ex-Situ-Raman-spektroskopischen Untersuchungen diskutiert. / Electrochemiluminescence (ECL) has been generated in solution phase using 9,10-diphenylanthracene (DPA) with TEAClO4 (or TBAClO4) in acetonitrile solvent. Triple potential step was used for the generation of ECL. It was found that anodic and cathodic ECL of equal intensities can be generated by proper choice of potential step magnitude, width and the waiting period (tw) between successive triple potential steps. ECL was then generated in conducting polymers poly(2-ethylhexyloxy-5-methoxy-1,4-phenylenevinylene) (MEH-PPV) and poly(2,3-dibutoxy-1,4-phenylenevinylene) (DB-PPV) by coating them on Pt electrodes and subjecting to potential steps in tetraalkylammonium salt solutions with acetonitrile. Similar to the case of solution phase ECL, symmetrical anodic and cathodic ECL could be observed by the appropriate choice of the potential step parameters. But the kinetics of the ECL was found to be different from that of the solution phase ECL. The time scale of the ECL process was found to be longer than that in the solution phase ECL. The nature of supporting electrolyte had a remarkable impact on the electrochemistry of conducting polymers. The reasons were analyzed by theoretical calculations evoking the concept of charge transport characteristics of conducting polymers. The rate constants of the ECL process were calculated by separate simulation procedure in the solution phase as well as in the polymer phase ECL. To enhance the stability of conducting polymers, synchrotron radiation induced cross-linking was performed. The effects were different from expected which were analyzed and rationalized by ex-situ Raman spectroscopic studies.

Le phénomène d’électro chimiluminescence (ECL), également appelé chimiluminescence électrogénérée, consiste en la génération de l’état excité d’un émetteur suite à des réactions de transfert d’électrons se produisant initialement à la surface de l’électrode. L’état excité ainsi produit retourne à l’état fondamental en émettant de la lumière. Les réactions ECL se classent principalement en 2 grandes voies mécanistiques: les réactions d’annihilation et les réactions impliquant un co-réactif sacrificiel. Cette dernière voie a conduit à de très nombreuses applications en chimie analytique. Dans ce manuscrit, j’ai présenté mes travaux de thèse qui ont suivis 3 directions complémentaires depuis l’échelle moléculaire jusqu’à l’échelle macroscopique: la recherche de nouveaux luminophores ECL, l’étude de films d’hydrogels stimulables et le développement de nouvelles applications analytiques de l’ECL.Dans une première partie, j’ai étudié les propriétés ECL de 3 types de luminophores organiques. Ces composés ont montré des caractéristiques électrochimiques et ECL remarquables. L’efficacité ECL de ces luminophores organiques peut être modulée enjouant sur leurs structures respectives. Des luminophores de type spirofluorène ont produit une émission ECL très intense et les nanoparticules organiques correspondantes ont pu être utilisées comme nano-émetteurs ECL. L’étude des propriétés électrochimiques, photochimiques et ECL de luminophores cationiques de type triangulène et hélicène a été réalisée et présentée avec un formalisme montrant un «mur» ECL ou une cartographie ECL complète.Dans une seconde partie, la préparation de films d’hydrogels thermo-stimulables à base de poly(N-isopropylacrylamide) ou pNIPAM incorporant des centres redoxRu(bpy)3 a été réalisée sur des électrodes de carbone vitreux (GCE) et aussi sur des fibres de carbone par polymérisation radicalaire induite électrochimiquement. Les études ECL sur les GCEs modifiées ont montré que le facteur principal gouvernant les propriétés ECL est la distance entre les sites Ru(bpy)3. Le dépôt de tels films de pNIPAM-Ru(bpy)3 par électrochimie bipolaire ouvre de nouvelles possibilités pour le développement de micro-objets stimulables hybrides. Dans une dernière partie, comme la chimie analytique constitue un des plus importants attraits de l’ECL, deux applications analytiques sont présentées en utilisant,d’une part, des co-réactifs de type amine modifié par l’acide phénylboronique, et,d’autre part, des faisceaux de fibres optiques recouverts d’or. La réaction de complexation de saccharides par le groupe phénylboronique modifie les propriétés électrochimiques du co-réactif amine en rendant son oxydation à l’électrode inefficace,ce qui provoque la diminution du signal ECL. En changeant la longueur de l’espaceur de ces co-réactifs qui portent deux groupements phénylboroniques, nous avons pu mesurer sélectivement la concentration de D-glucose et de D-fructose. Mon travail a enfin porté sur le développement d’un objet analytique basé sur un faisceau de fibresoptiques doré qui est adressé sans contact par électrochimie bipolaire. L’ECL ainsi générée du système Ru(bpy)32+/TPrA a permis de réaliser un outil activable à distance permettant une mesure déportée via le faisceau. Ce nouvel objet analytique original devrait permettre d’étendre les mesures ECL à des environnements confinés ou dangereux. / Electrogenerated chemiluminescence (ECL) involves the energetic electron transfer reactions at the electrode with the generation of excited state of emitter, which then relax to the ground state and emit light. These ECL reactions can be divided into two main pathways: the annihilation and sacrificial co-reactant reactions. The latter has found a lot of applications in analytical chemistry. In this thesis, ECL studies towardt hree complementary directions are presented, ranging from the molecular scale tomacroscopic scale : the research of new ECL luminophores, the study of stimuli-responsive hydrogel films, and the development of new ECL assays.Firstly, I have studied three types of organic dyes for ECL investigations. These organic dyes exhibit interesting electrochemical and ECL properties. ECL efficiencies of the organic dyes can be tuned by the modification of the structures. Spirofluorene dyes show strong ECL emission, and thus its fluorescence organic nanoparticles(FONs) prepared in water were used as ECL nano-emitters. We also established an energetic ECL “wall” representation and then move forward creating ECL “map”upon electrochemical, photoluminescence and ECL studies on cationic triangulenes and cationic helicenes dyes, respectively.Secondly, the preparation of thermo-responsive poly(N-isopropylacrylamide)(pNIPAM) hydrogel films covalently incorporating Ru(bpy)3 redox centers were achieved on glassy carbon electrode (GCE) or carbon fiber by electrochemically induced free radical polymerization. ECL studies on the modified GCEs have provided the main factor (the average distance of Ru(bpy)3 sites) that governs the ECL process, leading to deciphering the enhanced ECL in the films. The deposition of the films on carbon fiber by bipolar electrochemistry (BPE) has opened new route to for the development of smart hybrid micro objects. Finally, analytical application is one of the most important features of ECL. We presented two different ECL assays using either the phenylboronic acid modified amine based co-reactants or gold coated optical fiber bundle. The binding of saccharides with boronic acid modified tertiary amines makes the oxidation of amines group inefficient, which decreases ECL signal response. By changing linker length of a bis-boronic acid amine co-reactant, we are able to determine D-glucose and D-fructose selectively. We also studied the ECL generation of Ru(bpy)32+/TPrA systemon the gold coated optical fiber bundle in a wireless manner by BPE, then transmission and remote detection at the opposite end of the same object. This methodmay extend the applicability of ECL assays in the confined or hazardous environments. / 电化学发光（ECL）的发生是由于在电极表面通过电子转移反应生成了发光体的激发态跃迁到基态，并伴随着发光。这些电子转移反应可划分为两种主要的途径：正负自由基湮灭反应和共反应物反应。而后者被广泛应用于分析化学领域。在本论文中，我们在电化学发光领域中进行了广泛的研究，具体有三个研究方向：新型电化学发光光团的研究、响应水凝胶膜的制备以及电化学发光分析的研究。首先，我们选择了三种不同类型的有机荧光分子用于电化学发光的研究。这些有机荧光分子展现出许多电化学和电化学发光特性。其中，螺芴荧光分子展现出了非常强的电化学发光。而且用它制备的荧光有机纳米颗粒（FONs）在水相中也可以产生电化学发光。基于对阳离子型三角烯和阳离子型螺烯的电化学、光谱学以及电化学发光的研究，我们分别建立了鉴别电化学发光“墙”和“图谱”。其次，利用自由基电聚合的方法，我们实现了在玻碳电极和碳纤维表面上制备热刺激-响应的聚异丙基丙烯酰胺（p-NIPAM）共价嫁接三联吡啶钌Ru(bpy)3 荧光分子的水凝胶膜。通过对玻碳电极上水凝胶膜的电化学发光的研究，我们发现了控制水凝胶膜中电化学发光的主要因素，从而揭秘了水凝胶膜中电化学发光增强的成因。而且，利用双电极化学（BPE）的方法，我们将此类水凝胶膜的制备应用于碳纤维上，以发展灵敏杂化微米级器件。最后，鉴于化学分析是电化学发光最重要的特征，我们构建两种不同的电化学发光分析体系：一种是基于硼酸化学修饰的三丙胺共反应物；另一种是利用镀金光导纤维。硼酸对糖类的结合弱化了三丙胺的电化学氧化效率，因此影响电化学发光的强度。通过改变双硼酸修饰共混物之间碳链的长度，我们实现了对葡萄糖和果糖的选择性检测。我们还研究了在镀金光导纤维上三联吡啶钌/三丙胺体系的 电化学发光。此研究是在双电极体系进行的，镀金光导纤维无需外部接线，镀金部位产生的发光透过光纤传输的光纤的远端，再进行检测，因此达到了电化学发光的远程检测。这一方法可应用于狭窄危险环境中的电化学发光分析。