<p>   Contamination of surface and ground water from industrial wastes and anthropogenic activities represents one of the greatest challenges to the sustainable development of human society. Heterogeneous photocatalysis, a kind of advanced oxidation process characterized by the production of highly oxidative hydroxyl radicals, is a relatively novel subject with tremendous potential in water treatment applications.</p><p>    The purpose of this research was first to develop feasible hydroxyl radical detection methods, which can be used to evaluate efficiency of photocatalytic process, and second to prepare immobilized TiO2 films with high photocatalytic activities by the sol gel method.</p><p>    The feasibility of Indigo carmine and phthalic hydrazide as OH-radical probes was investigated. The organic dye Indigo carmine absorbs visual light strongly at 610 nm and its destruction can be monitored conveniently in a spectrophotometer. Results showed that both ^·OH and HO₂^·can bleach Indigo carmine, and the bleaching yield of ^·OH was pH independent. The photocatalytic dye bleaching in black light UV illuminated Degussa P25 TiO2 aerated suspensions was then investigated. A strong pH dependency of the bleaching yield was found.  This implies that the quantum yield of OH radical at pH 3 is one fourth compared to that at pH 10. The reaction of the OH radical with phthalic hydrazide will form strongly chemiluminescent 3-hydroxyphthalic hydrazide. Using the more specific phthalic hydrazide as OH radical probe, an even stronger pH dependent quantum yield of OH radical was found. At pH 10 the quantum yield reached the same magnitude as that obtained by using Indigo carmine, whereas the quantum yields at acidic pH were close to zero. However it was found that the addition of phosphate and fluoride anions can substantially enhance the OH radical yield at acidic pH by blocking the adsorption of phthalic hydrazide onto the TiO2 surfaces. Hence the adsorption of phthalic hydrazide to TiO2 is an important factor to consider when this method is used. <em></em></p><p>    Photocatalytic TiO2 films coated on metal plates were prepared by a sol gel method using titanium isopropoxide as TiO2 precursor and isopropanol as solvent. The photocatalytic activity of the obtained films was evaluated by bleaching of indigo carmine at pH 9 under black light UV irradiation. The effect of the molar ratio of isopropanol, water and hydrochloric acid to titanium isopropoxide was studied. It was also shown that the activities of TiO2 films are considerably influenced by calcination temperature, coating cycles and the supporting materials.</p> / <p>    Förorening av yt- och grundvatten från industrier och humana aktiviteter utgör en av de största utmaningarna för en hållbar utveckling av det mänskliga samhället. Heterogen fotokatalys, en slags avancerad oxidations process som kännetecknas av att starkt oxidativa hydroxylradikaler produceras, är en relativt ny teknik med stor potential för vattenrening.</p><p>    Ett syfte med detta licentiatarbete var först att utveckla och genomföra olika metoder för att detektera bildningen av hydroxylradikaler såväl i laboratoriet som i tekniska miljöer. Det andra syftet med arbetet var att syntetisera immobiliserade TiO2 filmer med hög fotokatalytisk effektivitet med en sol-gel metod.</p><p>    Möjligheten att använda indigokarmin och ftalhydrazid som OH-radikalprob undersöktes. Det organiska färgämnet indigokarmin absorberar synligt ljus starkt vid 610 nm vilket gör att dess nedbrytning lätt kan följas i en spektrofotometer. Resultaten av gammaradiolys visade att båda ^•OH och HO₂^• kan bleka indigokarmin och att den blekning som härrör från ^•OH var oberoende av pH. Fotokatalytisk blekning av indigokarmin med blacklight UV bestrålning av  Degussa P25 TiO2 suspensioner undersöktes sedan. Ett starkt pH-beroende av blekningsutbytet erhölls vilket tolkas som att kvantutbytet av OH-radikaler vid pH 3 är en fjärdedel jämfört med det vid pH 10.</p><p>    När ftalhydrazid reagerar med OH-radikaler bildas starkt kemiluminiscent 3-hydroxy-ftalhydrazid. Med denna  specifika OH-radikalprob, erhölls ett ännu starkare pH beroende. Vid pH 10 var kvantutbytet i paritet med det som erhölls med indigokarmin, medan kvantutbytet vid lågt pH var nära noll. Tillsats av fosfat-  och fluoridjoner visade sig avsevärt öka OH-radikalutbytet vid lågt pH-värde genom att blockera adsorption av ftalhydrazid på TiO2 ytorna. Adsorptionen av ftalhydrazid på TiO2 är således en viktig faktor när denna metod används.</p><p>    Fotokatalytiskt verksamma TiO2-filmer på metallplattor framställdes med sol-gel metoden med titan-isopropoxide som TiO2-prekursor och isopropanol som lösningsmedel. Den fotokatalytiska aktiviteten av TiO2-belagda plattor utvärderades genom blekning av indigokarmin vid pH 9 under blacklight UV-bestrålning. Effekten av olika proportioner mellan isopropanol, vatten och saltsyra till titan isopropoxide undersöktes. Det visade sig att denfotokatalytiska aktiviteten av TiO2-plattorna i hög grad påverkades av kalcineringstemperatur, beläggningscykler och materialet i plattorna.</p>

Contamination of surface and ground water from industrial wastes and anthropogenic activities represents one of the greatest challenges to the sustainable development of human society. Heterogeneous photocatalysis, a kind of advanced oxidation process characterized by the production of highly oxidative hydroxyl radicals, is a relatively novel subject with tremendous potential in water treatment applications.     The purpose of this research was first to develop feasible hydroxyl radical detection methods, which can be used to evaluate efficiency of photocatalytic process, and second to prepare immobilized TiO2 films with high photocatalytic activities by the sol gel method.     The feasibility of Indigo carmine and phthalic hydrazide as OH-radical probes was investigated. The organic dye Indigo carmine absorbs visual light strongly at 610 nm and its destruction can be monitored conveniently in a spectrophotometer. Results showed that both ·OH and HO2· can bleach Indigo carmine, and the bleaching yield of ·OH was pH independent. The photocatalytic dye bleaching in black light UV illuminated Degussa P25 TiO2 aerated suspensions was then investigated. A strong pH dependency of the bleaching yield was found.  This implies that the quantum yield of OH radical at pH 3 is one fourth compared to that at pH 10. The reaction of the OH radical with phthalic hydrazide will form strongly chemiluminescent 3-hydroxyphthalic hydrazide. Using the more specific phthalic hydrazide as OH radical probe, an even stronger pH dependent quantum yield of OH radical was found. At pH 10 the quantum yield reached the same magnitude as that obtained by using Indigo carmine, whereas the quantum yields at acidic pH were close to zero. However it was found that the addition of phosphate and fluoride anions can substantially enhance the OH radical yield at acidic pH by blocking the adsorption of phthalic hydrazide onto the TiO2 surfaces. Hence the adsorption of phthalic hydrazide to TiO2 is an important factor to consider when this method is used.     Photocatalytic TiO2 films coated on metal plates were prepared by a sol gel method using titanium isopropoxide as TiO2 precursor and isopropanol as solvent. The photocatalytic activity of the obtained films was evaluated by bleaching of indigo carmine at pH 9 under black light UV irradiation. The effect of the molar ratio of isopropanol, water and hydrochloric acid to titanium isopropoxide was studied. It was also shown that the activities of TiO2 films are considerably influenced by calcination temperature, coating cycles and the supporting materials. / Förorening av yt- och grundvatten från industrier och humana aktiviteter utgör en av de största utmaningarna för en hållbar utveckling av det mänskliga samhället. Heterogen fotokatalys, en slags avancerad oxidations process som kännetecknas av att starkt oxidativa hydroxylradikaler produceras, är en relativt ny teknik med stor potential för vattenrening.     Ett syfte med detta licentiatarbete var först att utveckla och genomföra olika metoder för att detektera bildningen av hydroxylradikaler såväl i laboratoriet som i tekniska miljöer. Det andra syftet med arbetet var att syntetisera immobiliserade TiO2 filmer med hög fotokatalytisk effektivitet med en sol-gel metod.     Möjligheten att använda indigokarmin och ftalhydrazid som OH-radikalprob undersöktes. Det organiska färgämnet indigokarmin absorberar synligt ljus starkt vid 610 nm vilket gör att dess nedbrytning lätt kan följas i en spektrofotometer. Resultaten av gammaradiolys visade att båda •OH och HO2• kan bleka indigokarmin och att den blekning som härrör från •OH var oberoende av pH. Fotokatalytisk blekning av indigokarmin med blacklight UV bestrålning av  Degussa P25 TiO2 suspensioner undersöktes sedan. Ett starkt pH-beroende av blekningsutbytet erhölls vilket tolkas som att kvantutbytet av OH-radikaler vid pH 3 är en fjärdedel jämfört med det vid pH 10.     När ftalhydrazid reagerar med OH-radikaler bildas starkt kemiluminiscent 3-hydroxy-ftalhydrazid. Med denna  specifika OH-radikalprob, erhölls ett ännu starkare pH beroende. Vid pH 10 var kvantutbytet i paritet med det som erhölls med indigokarmin, medan kvantutbytet vid lågt pH var nära noll. Tillsats av fosfat-  och fluoridjoner visade sig avsevärt öka OH-radikalutbytet vid lågt pH-värde genom att blockera adsorption av ftalhydrazid på TiO2 ytorna. Adsorptionen av ftalhydrazid på TiO2 är således en viktig faktor när denna metod används.     Fotokatalytiskt verksamma TiO2-filmer på metallplattor framställdes med sol-gel metoden med titan-isopropoxide som TiO2-prekursor och isopropanol som lösningsmedel. Den fotokatalytiska aktiviteten av TiO2-belagda plattor utvärderades genom blekning av indigokarmin vid pH 9 under blacklight UV-bestrålning. Effekten av olika proportioner mellan isopropanol, vatten och saltsyra till titan isopropoxide undersöktes. Det visade sig att denfotokatalytiska aktiviteten av TiO2-plattorna i hög grad påverkades av kalcineringstemperatur, beläggningscykler och materialet i plattorna.

Transparent conducting oxide (TCOs) thin films, including non-stoichiometric tin doped indium oxide (ITO) and aluminium doped zinc oxide (AZO), have found considerable applications in various displays, solar cells, and electrochromic devices, due to their unique combination of high electrical conductivity and optical transparency. TCO thin films are normally fabricated by sputtering, thermal vapour deposition and sol-gel method. Among them, sol-gel processing, which was employed in this project, is no doubt the simplest and cheapest processing method, The main objectives of this project were to produce indium tin oxides (ITO) and zinc aluminium oxides (AZO) nanoparticles with controlled particle size and morphology and to fabricate TCO thin films with high optical transmittance and electrical conductivity. In this research, hydrothermal method was used to synthesise ITO and AZO nanoparticles. Tin oxides, zinc oxides, ITO and AZO particles with the particle size ranging from 10 nm to several micrometers and different morphologies were synthesised through controlling the starting salts, alkaline solvents and hydrothermal treatment conditions. ITO and AZO thin films were fabricated via sol-gel technique through dip coating method. The effects of the starting salts, alkaline solvents, surfactant additives and coating and calcination conditions on the formation of thin films were investigated. XRD, TEM, FEG-SEM, DSC-TGA, UV-Vis spectrometer and four-point probe resistance meter were used to characterise the crystallinity, particle size, morphology, optical transmittance and sheet resistance of the particles and thin films. Crack-free thin films with high optical transmittance (>80% at 550 nm) and low sheet resistances (2.11 kΩ for ITO and 26.4 kΩ for AZO) were obtained in optimised processing conditions.

Le phénomène de relâchement de nickel des tubes de générateur de vapeur des centrales R.E.P. est responsable d'une grande partie de la contamination radioactive du circuit primaire. Une solution envisagée pour limiter ce relâchement est l'application d'un revêtement anticorrosion, côté interne des tubes. Ce travail vise à étudier la faisabilité et l'efficacité de ce type de traitement de surface dans les conditions du circuit primaire (320°C, 150 bars). L'étude a permis d'établir un procédé de synthèse par voie sol-gel compatible avec des substrats métalliques, conduisant à des films denses et mésoporeux à partir d'alcoxydes de métaux de transition, dont la réactivité est contrôlée par l'ajout de l'acétylacétone. La température de traitement thermique conditionne la cristallisation des films, la formation d'une couche enrichie en chrome contribuant à l'effet anticorrosion et la diffusion de nickel et de fer dans le film. Les films denses de ZrO2 présentent un meilleur effet barrière à la diffusion cationique et constitue une barrière anticorrosion. L'applicabilité des films de ZrO2 sur les tubes de générateur de vapeur à l'état de réception a été réalisée en adaptant l'épaisseur du film. Des essais de vieillissement dans les conditions du milieu primaire en autoclave et dans une boucle à recirculation ont été réalisés. Ces essais ont montré un phénomène de dissolution et reprécipitation des films de TiO2 tandis que les films de ZrO2 conservent davantage leur structure, malgré la formation de porosités en surface. Les films de ZrO2 vieillis pendant 500 h semblent conserver leurs propriétés de barrière à la diffusion de nickel. / Steam generator nickel release represents a major contribution to the radioactive contamination of the Pressurized Water Reactor primary circuit. One of the considered solutions is the deposition of a protective coating on the internal side of the alloy 690 tubes. The goal of this work is to study these coatings and their feasibility and efficiency in the primary circuit conditions (320°C, 150 bars). Firstly, a sol-gel thin film synthesis, leading to dense and mesoporous films, from transition metals alcoxides (butoxide titanium and propoxide zirconium) has been studied. Their reactivity is controlled by acetylacetone, which plays the role of complexing agent. The thermal treatment temperature appears to be a key parameter of the process, as it determines the oxide crystallization, the formation of a rich chromium layer below the film (which reinforces anticorrosion properties) and the nickel and iron diffusion in the film. ZrO2 coatings behave as cationic diffusion barriers and limit the corrosion. The applicability of ZrO2 coatings on industrial substrates, namely steam generators internal side with a 200 nm roughness, has been carried out by adapting the film thickness. Ageing tests in the primary circuit conditions have been conducted in an autoclave and a circulation loop. These tests have shown a dissolution – reprecipitation behavior of TiO2 coatings whereas ZrO2 coatings keep their structure despite the formation of surfacic porosities. ZrO2 dense coatings seem to keep limiting the nickel diffusion after 500 h of ageing in the primary circuit conditions.

The present work provides an insight in the development of silica films prepared by water-based sol-gel process. The weaknesses of the coating technology are identified, also solutions are discussed. The silica film is applied on aluminium alloy 6082-T6 and magnesium alloy AZ31. The development of the coating properties such as cost-efficiency, crack-free, self-healing and long-term corrosion protection is the main topic of this work. Cracking is the major drawback of silica films; the cracks are generated due to shrinkage of the film during the heat treatment, nanoparticles-doped silica film is successfully reduced the shrinkage which leads to crack-free silica films. The self-healing of the coated aluminium and magnesium samples is generated by corrosion inhibitors-doped silica film. When a defect appears in the film, the corrosion inhibitors leach out of the silica film to the defect area to heal the corroded surface. The long-term corrosion protection is realized by means of a mixture of corrosion inhibitors-doped silica film. / Die vorliegende Arbeit liefert einen Einblick in die Entwicklung von Silikafilmen, die mittels Sol-Gel-Prozess auf Wasserbasis hergestellt wurden. Die Schwächen der Beschichtungstechnologie werden dargestellt und Lösungen diskutiert. Der Silikafilm wird auf Aluminiumlegierung 6082-T6 und Magnesium-legierung AZ31 aufgebracht. Schwerpunkt dieser Arbeit ist die Entwicklung der Schichteigenschaften, wie Kosteneffizienz, Rissfreiheit, Selbstheilung so wie langfristiger Korrosionsschutz. Rissbildung ist ein wesentlicher Nachteil von Silikafilmen; rissfreie Filme wurden mittels nanopartikeldotierter Silikafilme hergestellt. Die Selbstheilung von Aluminium-und Magnesiumsubstraten mit Silikafilm wird durch den Effekt der wasserlöslichen Korrosionsinhibitoren generiert. Die Experimente haben gezeigt, dass die Proben mit inhibitordotierter Beschichtung selbst gegen Korrosion geschützt sind. Ein langfristiger Korrosionsschutz wird durch eine Mischung aus Korrosionsinhibitor-dotierten Silika-Film realisiert.