Le polyamide 66 est un polycondensat formé par condensation de l'acide adipique et de l'hexaméthylène diamine. La réaction a lieu sans catalyse. Cependant, elle peut être accélérée en présence de catalyseurs, les plus répandus étant les acides phosphorés organiques et minéraux. Aujourd'hui, on connaît peu de choses sur le mécanisme d'activation de la réaction. Dans un souci d'innovation et de compréhension, les recherches en catalyse de polycondensation du polyamide 66 se sont intensifiées ces dernières années. C'est dans cet optique que le travail de thèse a été réalisé. Les objectifs étaient de proposer et tester de nouveaux systèmes catalytiques et d'engager une recherche permettant de mieux comprendre le mécanisme de catalyse de polycondensation du polyamide 66. Nous avons mis en évidence une réelle spécificité du phosphore en catalyse. Des acides alkylphosphoniques porteurs de fonctions polaires se sont révélées particulièrement actifs en synthèse et en post condensation liquide. Grâce à des études sur des réactions modèles, l'hypothèse du passage par un intermédiaire réactionnel de type anhydride mixte, formé entre le catalyseur et l'acide adipique, a pu être confortée / Polyamide 6,6 is prepared by polycondensation of hexamethylene diamine with adipic acid The reaction occurs without catalyst. It can be accelerated using a catalyst, the most usual activators are organic and inorganic phosphorous acids. Today, we know little about the mechanism of activation of the reaction. To innovate and understand, researches in catalysis of polyamide 66 polycondensation have intensified in recent years. It is the reason for why thesis was done. The goal of the thesis was to propose and test new catalytic systems and to initiate a work to get a better understanding of the mechanism of polycondensation catalysis of polyamide 66. We have highlighted a real specificity of phosphorus in catalysis. Alkylphosphonic acids with polar functions were found to be particularly active in synthesis and post condensation liquid. Studies on model compounds have supported that the polycondensation may proceed through a reaction-typed mixed anhydride formed between the catalyst and adipic acid

La volonté croissante de diminuer l’empreinte écologique des matières plastiques favorise le développement de polymères et d’additifs issus de ressources renouvelables afin de limiter leur impact environnemental. Les retardateurs de flamme sont une famille d’additifs qui jouent un rôle crucial dans de nombreux domaines d’application où le risque d’incendie est avéré. Cette étude vise donc à développer de nouveaux systèmes retardateurs de flamme à partir de composés issus de la biomasse afin d’améliorer le comportement au feu d’un polymère bio-sourcé, l’acide polylactique (PLA). La lignine et la cellulose ont été choisies comme composés de base. Des procédés adaptés ont permis de transformer ces composés à l’état nanoparticulaire, puis ils ont été fonctionnalisés avec des produits phosphorés ou alors mélangés avec du polyphosphate d’ammonium, et incorporés dans l’acide polylactique au mélangeur interne. La stabilité thermique, l’inflammabilité et le comportement au feu des composites ainsi obtenus ont été étudiés. Les résultats obtenus avec certains systèmes sont prometteurs. / The growing desire to reduce the ecological footprint of plastic materials promotes the development of polymers and additives from renewable resources in order to limit their environmental impact. Flame retardants represent an important family of additives that play a crucial role in many fields where fire hazard is encountered. Thus this study aims at developing new flame retardant systems from biomass compounds to improve the fire behavior of polylactide (PLA), a bio-based polymer. Lignin and cellulose were chosen as pristine compounds. These compounds have been transformed into nanoparticles with adapted processes. Then, they were functionalized with phosphorous moieties or mixed with ammonium polyphosphate, and incorporated into polylactide with in internal mixer. Thermal, flammability and fire properties of these compounds were evaluated. The results obtained with some systems are promising.

The Atlantic salmon (Salmo salar) is an iconic species that dominates the global finfish production sector with increasing market demand. The Scottish industry and government alone aspires for expansion of the sector to 210,000 t by 2020 with 154, 000 t produced in 2013. As such, there are pressures to improve sustainable development in particular to minimise the genetic impact of escapees on wild populations and reduce sea lice infection which are required for the granting of “green licenses” in Norway. The use of triploidy has been tested in the 1980’s with little success owing to suboptimal rearing conditions leading to elevated mortalities, poorer growth and a higher prevalence of deformities, in particular of the skeleton. Collectively: recent success of triploid trout farming, expansion to the salmon production sector and potential resulting pressure on wild stocks through escapee increases have reinstated interest to implement artificially induced triploid Atlantic salmon in commercial production. As diploid Atlantic salmon have undertaken extensive domestication to achieve the high quality production and welfare standards observed to date, triploid conspecifics too require husbandry optimisation to realise potential. In particular, industrialisation requires that higher observations of deformities and inconsistent growth trajectories during seawater ongrowing be resolved through optimisation of rearing regimes and subsequent standardization of husbandry protocols. Triploids possess additional genomic material and increased cell size yet reduced frequency that reflects known differences in physiology and supports that, in effect, triploids should be considered as a new species relative to diploid conspecifics. Therefore, this doctoral thesis aimed to study nutrition and temperature effects on triploid Atlantic salmon traits throughout the production cycle from ‘egg to plate’. Nutrition trials aimed to improve growth potential and mitigate skeletal deformities both in freshwater (FW) and saltwater (SW) whilst attempts were made to define a window of smoltification to ensure optimal ongrowing performance. Finally, impacts of embryonic temperature regimes that are known to impact long term performance and deformity development in triploids, were examined in relation to DNA regulation and yolk composition in an attempt to underpin potential mechanisms for the environmental impact of temperature on developmental phenotype. One of the main restrictions to triploid Atlantic salmon implementation is the increased prevalence and severity of skeletal deformities, particularly after the maring phase. The work performed in this thesis first demonstrated that protein and/or phosphorous (P) supplementation throughout SW ongrowing not only reduced the level of severely deformed (≥ 10 deformed vertebrae observable by x-radiography) individuals by 30 % but also sustained 6.8 % faster growth and improved harvest grade compared to triploids fed a standard grower diet (chapter 2). Comparison of x-radiography and severely deformed individuals between harvest and sea transfer highlighted that protein and P supplementation arrested deformity development whereas prevalence increased in triploids fed a standard grower diet. This implied that severe deformities were of FW origin and strongly suggest requirement for improved nutrition in FW to optimise SW performance. Therefore investigation of higher dietary P inclusion in FW was investigated and results showed significantly reduced number of deformed vertebrae and no severely deformed individuals in those fed 19.7 g total P Kg-1 compared with those fed 13.0 & 16.7 g total P Kg-1 (chapter 3). Most deformities were localised in the central (vertebrae 27 – 31) and caudal (vertebrae 52 – 57) regions for all treatments. However, triploids fed lower dietary P displayed a particular increase in prevalence within the tail region (vertebrae 32- 47) which is consistent with SW ongrowing reports and results from chapter 2, further highlighting FW origin of higher vertebral deformities reported in SW ongrowing in triploids. Higher P supplementation in FW also significantly improved growth in triploid parr compared to diploids and lower supplementation. However, this effect did not transpire in later FW smolt stages where weights were significantly higher in triploids fed lower compared to higher P supplementation. Expression of target genes involved in osteogenesis and bone P homeostasis in vertebrates were then analysed and a ploidy effect of osteogenic genes alp, igf1r and opn as well as a dietary effect on P homeostasis gene fgf23 was apparent in the parr stages but not smolt. In addition, stronger ploidy-diet effects were also observed in parr stages for whole body mineral concentrations. Collectively, growth, gene expression and whole body mineral content results indicate these earlier parr life stages may be more sensitive to P supplementation. This pronounced effect may be a consequence of seasonal accelerated growth associated with this period, where higher temperatures were also observed. The potential for shorter P supplementation windows in commercial production was addressed in chapter 4 with hope to cut economic cost to raw mineral inclusion in feed and also mitigate potential anthropogenic eutrophication on the environment that may be induced by P leached through uneaten feed and faeces. Triploids were fed higher dietary P (17.4 g total P Kg-1) until either early (5 g) or later (20 g) parr stages, or smolt (83 g) and monitored for performance throughout freshwater (FW) development. During later parr development (30 g), x-radiography assessment demonstrated that increased dietary P reduced the number of deformities and severely deformed individuals with no indication that feeding P for shorter windows improved skeletal integrity. Hence, P supplementation may be required throughout FW development for optimal skeletal performance. In addition, no differences in deformities were observed between triploid treatments at smolt. An effect of dietary P supplementation on whole body mineral concentration was observed in the early and later parr stages that was not as pronounced as smolt, which is consistent with results in chapter 3. Together, these results indicate that skeletal assessment during early developmental stages may not reflect smolt performance most likely as a consequence of seasonal effects of improved linear growth in the cooler winter temperatures prior to smolt where reversible deformities observed at parr may also be alleviated. In the same study (chapter 4), the inclusion of the probiotic Pediococcus acidilactici (Bactocell™) was also tested as a means to enhance gut assimilation as suggested in previous studies and therefore reduce the levels of P supplementation. Results clearly indicate superior skeletal performance in parr (30 g) as well as significantly less deformed vertebrae and no severely deformed individuals. However, at smolt (~83g), no effects of the dietary probiotic treatment were observed which may also be attributed to seasonal effects. Overall, nutritional research clearly indicate triploids require higher dietary P for optimal growth and skeletal development, which although is not consistent between life stages, is ultimately required throughout FW for optimal skeletal development at smolt. The use of probiotics offer a promising avenue for reduced P requirement in FW feed and further research should verify results and assess long-term performance. Timing of SW transfer according to correct parr-smolt transformation (PST) is essential for survival and growth performance in ongrowing where feeding and growth rate accelerate post-transfer. So far, SW transfer regimes and in particular the smoltification ‘window’ remains loosely defined in triploid Atlantic salmon and it is crucial that this be addressed to ensure optimal ongrowing survival and performance.

The crisis of freshwater has been a big concern worldwide. Water contamination that occurs through the discharge of toxic pollutants from different natural and anthropogenic sources have worsened the situation. Adsorption has emerged as a simple and economical water treatment procedure although the challenge is to find the right adsorbent that can efficiently remove the target contaminant followed by their easy recovery from the reaction vessel. In this dissertation, I have focused on the synthesis, characterizations and applications of environmentally compatible and magnetic humic acid coated magnetite nanoparticles (HA-MNP) as a potential adsorbent for water purification. Phosphate is an essential nutrient for many plants and organisms in the environment. However, it can also cause water pollution when present in excess amounts. The adsorption experiments showed that the laboratory synthesized nanoparticles (HA-MNP) can remove more than 90% of phosphate from water mainly through the mechanism of chemisorption. The overall removal process is spontaneous, endothermic and favorable. Water contamination by arsenic is considered one of the biggest natural disasters in human history. In the study, HA-MNP has been applied for the successful trapping and separation of two highly toxic inorganic As species, As(III) and As(V) from water. The removal of As(V) was faster than As(III) for the same initial arsenic concentration and HA-MNP loading. The binding of As species is mainly attributed to three different phases, rapid surface association, intraparticle diffusion and equilibrium adsorption. Selenium is a micronutrient for humans that can be toxic at modest concentrations. The remediation of toxic selenium species, Se(IV) and Se(VI) by using HA-MNP has been found effective under a variety of environmental conditions except at highly alkaline pH and the presence of sulfate and phosphate in aqueous solution. Selenite or Se(IV) forms strong inner sphere complexes while Se(VI) forms relatively weaker outer sphere complexes with the adsorbent sites. The oxidation and adsorption of As(III) is explored by using the photocatalytic and adsorptive behavior of HA-MNP. The higher removal efficiency is attained through the reactive oxygen species mediated photo-conversion As(III) to As(V). Combination of oxygen and 350 nm light provides the best results.

Calixarenes, particularly calix[4]arenes, continue to attract considerable attention in synthetic chemistry, notably as platforms for designing sophisticated molecular cages and claw-like ligands. Incorporation of phosphorus containing fragments into the calix[4]arene framework gives rise to new class of phosphorus ligands, called “calixphosphines”, a class of molecules that combine a catalytic center (a transition metal) and a molecular receptor. This area of research has been growing rapidly in recent years. This thesis deals with the synthesis and a systematic study of conformational aspects of phosphorus functionalized calix[4]arene ligands and their palladium complexes. Several phosphorus functionalized calix[4]arene ligands and their (allyl) palladium complexes have been synthesized. The new compounds have been characterized by elemental analysis, NMR and IR spectroscopic data. The molecular structures of some representative compounds have been confirmed by single crystal X-ray diffraction studies. Chapter 1 provides a brief overview of phosphorus functionalized calix[4]arenes and their transition metal chemistry with emphasis on aspects related to the theme of the present study. The scope and aim of the present investigation is outlined at the end of this chapter. Chapter 2 presents the results obtained in the present investigation and a discussion of these results, especially spectroscopic and X-ray crystallographic data. The highlights of the present investigation and possible future directions are summarized at the end of this chapter. Chapter 3 contains relevant details of the experimental procedures for the synthesis of calix[4]arene phosphite ligands and their palladium complexes. Spectroscopic and analytical data of these compounds are also given in this chapter. The details of single crystal diffraction studies are included at the end of this chapter. The references to the literature are compiled at the end of the thesis and are indicated in the text by appropriate numbers appearing as superscripts. The compounds synthesized in the present study are represented by bold arabic numerals. The abbreviations employed in this thesis are those generally used in Chemical Abstracts.

Agriculture is one of the main sources of phosphorous and nitrogen (P and N) contributing to cultural eutrophication of freshwater lakes and estuaries. In cold regions, the effects of agricultural management practices used to mitigate the runoff loss of these nutrients remain uncertain. In particular, the use of forage crops and minimum tillage, have not reduced some forms of P and N in runoff to streams, in part, as a result of freeze-thaw induced losses of mobile P and N from forages and crop residues. The purpose of this research is to improve the current understanding of the controls on P and N loss from Canadian Prairie fields to ultimately aid in the development and evaluation of beneficial agricultural management practices that perform predictably in cold regions. This study aims to provide new insights into the effects of cold regions hydrological processes on runoff quality through the development and application of a novel inductive - deductive modelling approach. Runoff flowpaths resulting from the three infiltration regimes identified for frozen soils (Granger et al., 1984) are hypothesized to impact the chemistry of field scale meltwater runoff by varying meltwater interaction with agricultural soils and vegetation. Hydrochemistry data from six intensively monitored minimum tillage and forage cropped fields in South Tobacco Creek, Manitoba were used to develop a nutrient model to integrate with a physics-based hydrological modelling platform that can represent the frozen soil infiltration regimes, in addition to other important cold region hydrological processes. The inductive development of a nutrient model, integrated with a deductive physics-based hydrological platform, enabled the modelling of meltwater flowpaths and freeze-thaw induced losses from vegetation. Further testing of the developed model and field experimentation are required to test the hypothesis that runoff generated over a basal ice layer eliminates the transfer of soil nutrients to runoff. Comparison of predicted and observed field scale runoff concentrations and masses suggest that this method of inductive-deductive model development has potential to predict the performance of agricultural management practices in cold regions.

The aim of this report is to present a proposal for a constructed wetland as a complement toHaga treatment plants, Surahammar. First, a literature study in the subject was made andthen a case study was conducted, where Ekeby and Trosa wetland was visited. Parallel anarchival study was performed and several field visits were made to the proposed site toinvestigate the local conditions for constructing a wetland adjacent to Haga treatment plants.Finally, a proposal for the design of the constructed wetland was made. The proposalincludes an oxygenating area for reduction of ammonium to nitrate followed by a system ofdams and channels to convert nitrate to nitrogen diffuses into the air. Phosphorus removaltakes place throughout the residence time in the wetland, as well as reduction of the bacterialload. Expected results for the outgoing water from the wetland is that P-tot can be reduced to0.10-0.11 mg / l, N-tot can be reduced to 11-14 mg / l, a reduction of E. coli, fecal streptococciand intestinal streptococci by 70-99% and a little reduction of residues from drugs take placedue to oxygenation and the UV-irradiation of the water. / Allt vatten här på jorden ingår i den hydrologiska cykeln, så även det renade avloppsvattnet.Avloppsvatten innehåller bland annat kväve och fosfor vilka bidrar till övergödningen avsjöar, vattendrag och hav. Övergödningen är ett utbrett problem och i Västmanland är 53 %av länets sjöar och vattendrag utsatta för det.Syftet med den här rapporten är att ta fram ett förslag till våtmark för Haga reningsverk,Surahammar. Först har information om hur en våtmark kan användas för efterpolering avrenat avloppsvatten tagits fram för att därefter nyttjas som grund i ett förslag till våtmark förHaga reningsverk, Surahammar. Först gjordes en litteraturstudie inom ämnesområdet ochdärefter gjordes en fallstudie där Ekeby och Trosa våtmark besöktes. Parallellt utfördes enarkivstudie och flera områdesbesök på den tilltänkta platsen för att få fram vilkaförutsättningar som finns för att anlägga en våtmark i anslutning till Haga reningsverk ochsist gjordes ett förslag på en våtmark.Anledningen till att anlägga en våtmark kan vara flera, men att avskilja fosfor, kväve samtbryta ner organiskt material är vanliga orsaker. En våtmark fungerar som ett kompletterandesteg till det ordinarie reningsverket och minskar belastningen på recipienten. Hur mycketutsläppen reduceras beror på många faktorer och egenskaper där utformning, vattnetsuppehållstid, syresättning och tillgång till organiskt material är viktiga men även parametrarsom förbehandling av avloppsvattnet och belastningen på våtmarken spelar stor roll. Ävenväxtligheten i våtmarken påverkar det slutliga resultatet, både vad det gäller vad och hurmycket som avskiljs. Avskiljningen av fosfor och kväve sker främst genom sedimentation ochnäringsupptag till växter samt att kväve även avskiljs vid denitrifikation. För den långsiktigaavskiljningen av kväve från vattnets kretslopp är nitrifikation och denitrifikation de som harstörst betydelse. Nitrifikationsprocessen är när ammoniumjoner omvandlas till nitratjoneroch det kräver god tillgång på syre, därefter följer denitrifikationen när nitratjonerna undersyrefria förhållanden omvandlas till kvävgas som diffunderar upp i atmosfären. För attnitrifikationsprocessen ska kunna fungera krävs antingen att det finns ennitrifikationsanläggning i reningsverket eller en syresättningsfas i våtmarken. Det kan skapasgenom att börja våtmarken med en översilningsäng, där det renade avloppsvattnet får strilaner över en bevuxen äng. Vattnet syresätts av luften och nitrifikationsbakterier som trivs bra iväxtligheten utför nitrifikationsprocessen och omvandlar ammoniumjonerna till nitratjoner.Därefter följer ett system av dammar och kanaler där denitrifikationsprocessen tar vid ochomvandlar nitratjonerna till harmlöst kväve. Även i dammar och kanaler har växtlighetenstor betydelse eftersom det bildas biofilm, ett tunt lager av bakterier på växterna, som deltar iden biologiska processen av nedbrytning av organiskt material samt avskiljning av fosfor ochkväve i vattnet.När vattnet passerar genom våtmarken sker också en reducering av antalet bakterier somfinns i det renade avloppsvattnet. Mätningar av E. coli, fekala streptokocker, Koliformabakterier och intestinala enterokocker visar på att halterna kan reduceras kraftigt. Även vissaläkemedel visar tendenser till att brytas ned, men läkemedel är en komplex grupp och detfinns begränsad kunskap om deras omvandling och påverkan i miljön. Det finns dock indikationer om att nedbrytningen av läkemedelsrester är högre i de våtmarker som harsyresättande delar som till exempel översilningsäng.Haga reningsverk är beläget strax utanför Surahammars tätort och har idag en kulvert somleder ut det renade avloppsvattnet från verket till recipienten. Mellan Haga och recipientenligger ett markområde på cirka 750 gånger 750 meter som skulle kunna utnyttjas till envåtmark. Redan idag ligger utsläppsvärdena för Haga reningsverk under de tillåtna halternamen en önskan att ytterligare minska belastningen på miljön finns. Vid analysering avutsläppsvärden för Haga reningsverk framkom att ammoniumkväve utgör en stor andel avutgående totalkväve samt att halterna av totalfosfor, BOD7 och suspenderade ämnen är lågatill måttliga. Ett förslag på våtmark anpassat till de förutsättningar som råder vid Hagareningsverk har tagits fram och presenteras i rapporten. Våtmarken föreslås innehålla tvåsektioner med först en översilningsäng för att reducera den höga andelen ammoniumkväveoch därefter ett damm och kanalsystem för att reducera nitratkvävet. Under hela processensker avskiljning av fosfor samt reducering av bakterier och en viss nedbrytning avläkemedelsrester. Förväntade resultat för det utgående vattnet från våtmarken är att P-totkan reduceras till 0,10–0,11 mg/l, N-tot kan reduceras till 11–14 mg/l, en reducering av E.coli, fekala streptokocker och intestinala streptokocker med 70-99 % samt att en vissminskning sker av läkemedelsrester tack vare syresättning och solens UV-bestrålning avvattnet.

Human urine is a   valuable resource which has good potential to be used as a fertilizer all   over the world. In the developing countries sanitation and food security are   both issues that need urgent attention.    A urine separation toilet can be constructed with minimal investment   in the Nicaraguan context, and the usage of the urine as a fertilizer can   help establish higher yields and is a good alternative to chemical   fertilizers. This field experiment is trying this in practice in the context   of rural Nicaragua, to determine the effect of urine on two plants on. For   this study, the common bean (Phaseolus vulgaris) and the Chaya (Cnidoscolus   aconitifolius) was selected and the results confirm that urine has potential   as a fertilizer in the Nicaragua context. The common bean yield was twice as   large after urine fertilization and the Chaya reacted positively to urine   fertilization. For urine separation purposes, two different separators were   constructed on the site to showcase the benefits with separating the urine   from the faeces, creating lower latrine volume and better sanitation in the   outhouse. The risks associated with human urine are low if the urine is   separated securely to avoid crosscontamination from faeces. If a   safety-barrier system is adopted, the overall risks with using urine as a   fertilizer are negligible. The spreading potential of urine separation and   fertilization in rural Nicaragua is high, but more experiments and   demonstrations are needed to reach adopters of the technology. / La orina humana es un recurso valioso que tiene un   buen potencial para ser utilizado como fertilizante en el mundo entero. En   los países en vías de desarrollo, el saneamiento y la seguridad alimentaria   son dos temas que necesitan atención urgente. Un inodoro de separación de   orina puede ser construido con una inversión mínima en el contexto   Nicaragüense, y el uso de la orina como fertilizante puede ayudar a   establecer mayores rendimientos y es una buena alternativa a los   fertilizantes químicos. Este experimento de campo está probando esto en la   práctica en el contexto de Nicaragua rural, para determinar  la diferencia en  crecimiento entre dos cultivos con y sin   fertilización de orina. Para este estudio se seleccionó el frijol común   (Phaseolus vulgaris) y la Chaya (Cnidoscolus aconitifolius) El rendimiento de   frijol fue dos veces mayor después de la fertilización de la orina y el Chaya   reaccionó positivamente a la fertilización de la orina. Para fines de   separación de orina, se construyeron dos separadores diferentes en el sitio   para mostrar los beneficios con la separación de la orina de las heces,   creando un menor volumen de letrina y un mejor saneamiento. Los riesgos asociados con la orina humana son bajos   si la orina se separa con seguridad para evitar la contaminación cruzada de   las heces. Si se adopta un sistema de barrera de seguridad, los riesgos   generales con el uso de orina como fertilizante son insignificantes. El   potencial de propagación de la separación de orina y la fertilización en   Nicaragua rural es alto, pero se necesitan más experimentos y demostraciones   para llegar a los usuarios de la tecnología. / <p>2017-06-02</p>

The topic of this thesis is the impact of fish pond harvest on water quality especially on concentration of suspended solids and phosphorous. Goal of the study is to contribute to ongoing discussion about carp aquaculture's role in fresh water pollution. Sampling was carried out in five carp ponds in the Třeboňsko Protected Landscape Area. Main monitored parameters were concentration of suspended solids and total phosphorous during pond drainage and fish harvest.Results of the study confirmed very negative impact of fish harvest on water quality in recipient water.

Made available in DSpace on 2016-06-02T19:56:49Z (GMT). No. of bitstreams: 1 4974.pdf: 3642452 bytes, checksum: 9983d14f77babcbd0c76cb3ef274c7c6 (MD5) Previous issue date: 2013-02-18 / Universidade Federal de Sao Carlos / Mo, NiMo or NiMoP HDS catalysts were supported on Al2O3, Al2O3-TiO2 or TiO2. These supports were synthesized via sol-gel and in the case o TiO2 it was used a commercial sample. The active phases were introduced by impregnation. Supports and catalysts in the oxide form were characterized by X-ray diffraction (XRD), diffuse reflectance UV-Vis spectroscopy (DRSUV-Vis), thermogravimetric analyses (TG), temperature-programmed reduction with H2 (TPR-H2), N2 adsorption/desorption, energy dispersive X-ray spectroscopy (EDS), X-ray fluorescence (XRF), temperature-programmed desorption of NH3 (TPD-NH3), high resolution transmission electron microscopy (HRTEM) and evaluated at 300°C in the HDS of thiophene, used as a model molecule. Alumina presented a high specific surface area and meso/macroprous characteristics, allowing a high dispersion of the active phases, as was evidenced by XRD and DRSUV-VIS data. A HRTEM image of a NiMo/Al2O3 catalyst showed the presence of crystalline MoS2 whose activity was substantially promoted by the presence of Ni. The NiMo catalysts were active in the HDS of thiophene, however, the activity was enhanced significantly by the incorporation of P. This result corroborates the positive influence of P in the preparation of HDS catalysts. It was suggested that P must participate as promoter in the formation of the NiMoS phase during the sulfidation process of the Ni and Mo oxides. The supported NiMoP catalysts prepared in this work were more active than a commercial NiMoP/ Al2O3 catalyst, with this result validating the preparation procedures used here. The titania addition in the alumina framework led to NiMo catalysts possessing lower activity. That behavior was attributed to the formation of Ni and Mo sulfides without interaction diminishing the generation NiMoS phase, which is highly active in the HDS of sulfured organic compounds. / Catalisadores para hidrodessulfurização (HDS) contendo Mo, NiMo ou NiMo e o aditivo fósforo (P), foram suportados sobre Al2O3, Al2O3-TiO2 ou TiO2. A alumina e a alumina-titânia foram sintetizadas via sol-gel e, no caso da titânia pura, utilizada uma amostra comercial. A introdução dos sais precursores da fase ativa foi realizada via impregnação. Suportes e catalisadores na forma de óxidos foram caracterizados através de difração de raios X (DRX), espectroscopia por refletância difusa no ultravioleta visível (DRSUV-VIS), termogravimetria (TG), redução com hidrogênio à temperatura programada (RTP-H2), adsorção/dessorção de N2, espectroscopia de energia dispersiva de raios X (EDX), fluorescência de raios X (FRX), dessorção de amônia a temperatura programada (TPD-NH3), microscopia eletrônica de transmissão de alta resolução (HRTEM) e avaliados a 300&#8304;C na HDS do tiofeno. A alumina apresentou uma alta área superficial específica e características meso/macroporosa, possibilitando alta dispersão das fases ativas, conforme evidenciado por DRX e dados de DRSUV-VIS. A imagem de HRTEM do catalisador NiMo/Al2O3 mostrou a presença de MoS2 cuja atividade foi promovida substancialmente pela presença de Ni. Os catalisadores NiMo sobre os suportes utilizados foram ativos no HDS do tiofeno, entretanto, essa atividade foi melhorada pela incorporação de P. Esse resultado ratifica a influência positiva da utilização desse aditivo na preparação de catalisadores de HDS. O fósforo deve atuar como um promotor na formação de espécies NiMoS durante o processo de sulfetação dos óxidos de Mo e Ni. Os catalisadores NiMoP preparados neste trabalho apresentaram atividade específica superior à de um catalisador NiMoP/Al2O3 comercial, o que valida os procedimentos de preparação utilizados no trabalho. A adição de titânia na alumina durante a síntese sol-gel conduziu a catalisadores com menor atividade. Esse resultado foi atribuído à formação de sulfetos de Ni e Mo não interativos, com a consequente diminuição da formação da fase NiMoS de alta atividade no HDS de compostos organo-sulfurados.