Zeolites were used in this study to remove two types of non-radioactive ions (Cobalt-59 and Strontium-89) from wastewater. This was designed to model the use of ion-exchange technique to remove radioactive Co-60 and Sr-90 from low level wastewater from Al-Tuwaitha site. Al-Tuwaitha site is a nuclear research in Iraq was used for radio-medical and radio-chemical purposes before 1990. In this study, hierarchical microporous/macroporous structures were developed to overcome the diffusivity problem using zeolite. Diatomite and carbon were used to prepare the composite adsorbents by incorporating them with three types of zeolites (A, Y and clinoptilolite). From the XRD, SEM and EDAX measurement it was confirmed that successfully prepared of Iraqi palm tree leafs-Clinoptlolite (IPClinp) and Tamarind stones-Clinoptilolite (TSClinp) composites were obtained in this study as there is no evidence in literature of this being carried out before. The carbons were prepared successfully through the Pyrolysis method for 2h at 900°C in an inert atmosphere from two types of raw waste plant materials of Iraqi Palm Tree leafs (IP) and Tamarind stones (TS). For both types of carbons, the SEM images show organised porosities in different shapes. A third material used as a zeolite scaffold was diatomite (Celatom FW-14) a readily available natural material (dead algae).A hydrothermal treatment was used to build the hierarchical structure of zeolite onto carbon and diatomite materials, the scaffolds were seeded with nano-zeolite crystals prior to the treatment and thereafter mixed with the zeolite gel composition mixture in a stainless steel autoclave. Zeolite seeds were prepared using ball mill method to reduce the particle size of the commercial zeolite to sub-micron range for each type of zeolite. The surface area, morphology, element compositions and structure for each type of zeolite and composite material were characterised using BET method, SEM, EDAX and XRD. The amounts of each type of zeolite on the carbon composites were determined using TGA while that of the diatomite composite was determined by gravimetric analysis. The results show that each type of zeolite was successfully deposited and uniformly organised onto the surface of all support materials. All pure zeolites and composite materials were successfully tested to remove Co2+ and Sr2+ ions from aqueous solutions. It was found that the composite materials had higher ability to remove both ions relative to the pure zeolites. This increase is attributed to the deposition of zeolite (microporous) onto the macroporous structure (carbon and diatomite) which increased the flow accessibility within zeolite in the hierarchical structured composites. Comparison of the removal between the two metal ions indicates that all of the materials had higher uptake for Sr2+ than Co2+ ions. The highest adsorption capacities were realised with Tamarind Stone–ZeoliteA (TSA) in the order 120mg.gz-1and 290mg.gz-1 for Co2+ and Sr2+ ions, respectively. The effect of the experimental variables shows increasing uptake with increasing pH and initial ion concentrations while it decreased with increasing the solution temperature. The Co2+ loaded composites was subjected to vitrification process at 12000C for 2h. The encapsulated composites were leached for 90 and 120 days and no significant Co2+ was recorded in the leached solution. The results show that the composite materials can be used effectively to remove the radioactive ion of Co-60 and Sr-90 ion as they display the same chemical behaviour as Co-59 and Sr-89 studied in this work.

Made available in DSpace on 2014-12-17T14:07:00Z (GMT). No. of bitstreams: 1 RenataPAS_DISSERT.pdf: 2030872 bytes, checksum: b1f1838ae20a1cf415bfd28d267a0046 (MD5) Previous issue date: 2011-10-17 / Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico / The effluents released by the textile industry have high concentrations of alkali, carbohydrates, proteins, in addition to colors containing heavy metals. Therefore, a filter was prepared aiming primarily to the removal of color. In order to prepare this filter, rice hulls and diatomite were used, which have in their structure, basically amorphous hydrated silica. The silica exists in three crystalline forms: quartz, tridymite and cristobalite. In accordance with the above considerations, this study was divided into two stages; the first corresponds to the preparation of the filter and the second to carry out the tests in the effluent/filter in order to verify the efficiency of the color removal. First, the raw material was subjected to a chemical analysis and XRD, and then the diatomite was mixed, via humid, with a planetarium windmill with 20 %, 40 %, 60 % and 80 % of rice husk ash. To the mixture, 5 % carboxymethylcellulose (CMC) was added as a binder at room temperature. The samples were uniaxially compacted into metallic matrix of 0.3 x 0.1 cm? of area at a pressure of 167 MPa by means of hydraulic press and then sintered at temperatures of 1,000 ?C, 1,200 ?C and 1,400 ?C for 1 h and submitted to granulometry test using laser, linear retraction, water absorption, apparent porosity and resistance to bending, DTA, TMA and XRD. To examine the pore structure of the samples scanning electron microscope (SEM) was used. Also tests were carried out in a mercury porosimeter to verify the average size of the pores and real density of the samples. In the second stage, samples of the effluent were collected from a local industry, whose name will be preserved, located in Igap?, in the State of Rio Grande do Norte - RN. The effluent was first pretreated before filtration and then subjected to a treatment of flotation. The effluent was then characterized before and after filtration, with parameters of color, turbidity, suspended solids, pH, chemical and biochemical oxygen demand (COD and BOD). Thus, through the XRD analysis the formation of cristobalite α in all samples was observed. The best average size of pore was found to be 1.75 μm with 61.04 % apparent porosity, thus obtaining an average 97.9 % color removal and 99.8 % removal of suspended solid / Os efluentes liberados pela ind?stria t?xtil possuem altas concentra??es de ?lcalis, carboidratos, prote?nas, al?m de corantes contendo metais pesados. Assim, foi produzido um filtro visando principalmente ? remo??o da cor. Para sua obten??o foi usado a casca de arroz carbonizada e a diatomita, que possuem basicamente s?lica amorfa hidratada na estrutura. A s?lica apresenta-se sob tr?s formas cristalinas: Quartzo, tridimita e cristobalita. De acordo com as considera??es citadas, este estudo foi divido em duas etapas, a primeira etapa corresponde ? obten??o do filtro e a segunda parte a realiza??o dos ensaios no efluente/filtro, tendo em vista verificar a efici?ncia da remo??o da cor. Primeiramente, a mat?ria-prima foi submetida a uma an?lise qu?mica e de DRX, em seguida a diatomita foi misturada, via ?mido, em um moinho planet?rio com 20 %, 40 %, 60 % e 80 % de cinza de casca de arroz. Foi adicionada a mistura 5 % de carboximetilcelulose (CMC) como ligante a temperatura ambiente. Os corpos de prova foram compactados uniaxialmente em matriz met?lica de 0,3 x 0,1 cm? de ?rea a uma press?o de 167 MPa atrav?s de prensa hidr?ulica e posteriormente sinterizados em temperaturas de 1.000?C, 1.200?C e 1.400?C por 1 h e submetidos a ensaios de granulometria a laser, retra??o linear, absor??o de ?gua, porosidade aparente, resist?ncia ? flex?o, DTA, DTG e DRX. Para analisar a estrutura de poros das amostras foi utilizado um microsc?pio eletr?nico de varredura (MEV) e foi realizados ensaios em um poros?metro de merc?rio para verificar o tamanho m?dio dos poros e densidade real das amostras. Na segunda etapa, foi feito a coleta das amostras do efluente de uma empresa, cujo nome ser? preservado, alocada em Igap? RN. O efluente sofreu um pr?-tratamento antes da filtra??o sendo assim submetido a um tratamento de flota??o. O efluente foi ent?o caracterizado antes e depois da filtra??o, com par?metros de cor, turbidez, s?lidos suspensos, pH, demanda qu?mica e bioqu?mica de oxig?nio (DQO e DBO). Assim, atrav?s da analise de DRX, foi observado forma??o de cristobalita α em todas as amostras. O melhor tamanho m?dio de poro encontrado foi de 1,75 μm com porosidade aparente foi 61,04 %, obtendo assim uma remo??o de cor m?dia de 97,9 % e remo??o de s?lido suspensos de 99,8 %

Made available in DSpace on 2014-12-17T14:07:07Z (GMT). No. of bitstreams: 1 IrantecioMF_DISSERT_Parcial.pdf: 354207 bytes, checksum: e43a8d49123a8e937d996a1e4e80ba39 (MD5) Previous issue date: 2012-09-28 / Lightweight oilwell cement slurries have been recently studied as a mean to improve zonal isolation and sheath-porous formation adherence. Foamed slurries consisting of Portland cement and air-entraining admixtures have become an interesting option for this application. The loss in hydrostatic pressure as a consequence of cement hydration results in the expansion of the air bubbles entrapped in the cement matrix, thus improving the sheath-porous formation contact. Consequently, slurries are able to better retain their water to complete the hydration process. The main objective of the present study was to evaluate the effect of the addition of an air-entraining admixture on the density, stability and permeability of composite slurries containing Portland cement and diatomite as light mineral load. Successful formulations are potential cementing materials for low fracture gradient oilwells. The experimental procedures used for slurry preparation and characterization were based on the American Petroleum Institute and ABNT guidelines Slurries containing a pre-established concentration of the air-entraining admixture and different contents of diatomite were prepared aiming at final densities of 13 to 15 lb/gal. The results revealed that the reduction of 15 to 25% of the density of the slurries did not significantly affect their strength. The addition of both diatomite and the air-entraining admixture increased the viscosity of the slurry providing better air-bubble retention in the volume of the slurry. Stable slurries depicted bottom to top density variation of less than 1.0 lb/gal and length reduction of the stability sample of 5.86 mm. Finally, permeability coefficient values between 0.617 and 0.406 mD were obtained. Therefore, lightweight oilwell cement slurries depicting a satisfactory set of physicochemical and mechanical properties can be formulated using a combination of diatomite and air-entraining admixtures for low fracture gradient oilwells / Atualmente, busca-se a formula??o de pastas de cimento leves para prevenir o fraturamento de forma??es de baixa resist?ncia ou depletadas e combater a perda de circula??o, com boa ader?ncia e isolamento hidr?ulico entre cimento e meio poroso. O cimento espumado composto pela mistura de cimento com incorporador de ar ? um material alternativo para essa aplica??o. A perda de press?o hidrost?tica durante o processo de hidrata??o causa expans?o das bolhas de g?s, mantendo o grau de contato cimento-meio poroso, diferentemente do que ocorre apenas com o uso do cimento tradicional. A ader?ncia entre o cimento e o meio poroso (forma??o rochosa) faz com que haja estabilidade da pasta, impedindo a perda de ?gua do cimento no estado fresco para o meio. O presente trabalho tem como objetivo estudar a estabilidade e a permeabilidade de comp?sitos ciment?ceos contendo diatomita (carga leve) e incorporador de ar, verificando se o uso desses aditivos ? vi?vel para cimentos projetados para ambientes de baixo gradiente de fratura. A metodologia empregada no trabalho consiste na prepara??o e avalia??o de pastas comp?sitas, por meio de procedimentos adotados pelo American Petroleum Institute e pela Associa??o Brasileira de Normas T?cnicas. Partiu-se de uma dosagem fixa do incorporador de ar e variou-se a concentra??o de diatomita. As densidades calculadas foram 13,0 lb/gal, 14,0 lb/gal e 15,0 lb/gal, com o intuito de observar a contribui??o do fator ?gua/cimento na estabiliza??o das espumas geradas pela adi??o do incorporador de ar em rela??o a uma pasta padr?o, sem incorporador de ar. Os resultados revelaram que as pastas tiveram suas densidades reduzidas entre 15% e 25%, com a adi??o do incorporador de ar e diatomita e boa resist?ncia mec?nica. O aumento da viscosidade nas formula??es com diatomita proporcionou maior reten??o das bolhas, visto que houve redu??o acentuada da migra??o de ar para a superf?cie do cimento durante cura em repouso. Observou-se que pastas est?veis apresentaram varia??o entre o valor de densidade de fundo e topo de 0,96 lb/gal e rebaixamento de topo de 5,86 mm, al?m de baixos coeficientes de permeabilidade (0,617 mD a 0,406 mD). Concluiu-se que ? poss?vel formular pastas ciment?ceas espumadas de baixa densidade com propriedades mec?nicas e reol?gicas satisfat?rias, al?m de boa estabilidade e baixa permeabilidade, a partir de uma combina??o de cimento, diatomita e incorporador de ar. Os materiais resultantes s?o adequados visando ? cimenta??o de po?os de petr?leo com forma??es de baixa resist?ncia ou depletadas / 2020-01-01

Made available in DSpace on 2014-12-17T14:08:50Z (GMT). No. of bitstreams: 1 MarcoABL_DISSERT.pdf: 3031485 bytes, checksum: ee9422376e7cb63c045cc578494d0199 (MD5) Previous issue date: 2011-02-08 / Cementing operations may occur at various stages of the life cycle of an oil well since its construction until its definitive abandonment. There are some situations in which the interest zones are depleted or have low fracture pressure. In such cases, the adoption of lowdensity cement slurries is an efficient solution. To this end, there are basically three ways to reduce the density of cement slurries: using microspheres, water extending additives or foamed cement. The objective of this study is to formulate, to study and to characterize lowdensity foamed cement, using an air entrainment surfactant with vermiculite or diatomite as water extenders and stabilizers. The methodology consists on preparation and evaluation of the slurries under the American Petroleum Institute (API) and the Brazilian Association of Technical Standards (ABNT) guidelines. Based on calculated densities between 13 and 15 ppg (1.559 and 1.799 g/cm3), the slurries were prepared with fixed surfactant concentration, varying the concentrations of vermiculite and diatomite and were compared with the base slurries. The results of plastic viscosity, yield point and gel strength and the compressive strength for 24 h showed that the slurries presented suitable rheology and mechanical strength for cementing operations in oil wells, and had their densities reduced between 8.40 and 11.89 ppg (1.007 and 1.426 g/cm3). The conclusion is that is possible, under atmospheric conditions, to obtain light weighted foamed cement slurries with satisfactory rheological and mechanical properties by means of air entrainment and mineral additions with extenders and stabilizers effects. The slurries have great potential for cementing operations; applicability in deep wells, in low fracture gradient formations and in depleted zones and bring cost savings by reducing the cementing consumption / As opera??es de cimenta??o podem ocorrer em diversas etapas do ciclo de vida de um po?o, desde a sua constru??o at? seu abandono definitivo. H? situa??es em que as zonas de interesse se apresentam depletadas ou com baixa press?o de fratura. Nesses casos, a ado??o de pastas cimentantes de baixa densidade constitui solu??o eficiente. Para tanto, h? basicamente tr?s maneiras de reduzir a densidade de pastas de cimento: usando microesferas, aditivos estendedores de ?gua ou pastas espumadas. O objetivo deste trabalho ? formular, estudar e caracterizar pastas cimentantes espumadas de baixa densidade, utilizando um surfactante incorporador de ar juntamente com adi??es de vermiculita ou diatomita como estendedores e estabilizantes. A metodologia do trabalho consiste na prepara??o e avalia??o das pastas por meio de procedimentos adotados pelo American Petroleum Institute (API) e pela Associa??o Brasileira de Normas T?cnicas (ABNT). Partindo de densidades calculadas entre 13 e 15 lb/gal (1,559 e 1,799 g/cm3), as pastas foram preparadas com dosagem fixa do surfactante, variando as concentra??es de vermiculita e diatomita e foram comparadas com pastas base. Os resultados dos ensaios que determinam viscosidade pl?stica, limite de escoamento e for?as g?is, bem como os de resist?ncia ? compress?o para tempos de 24 h mostraram que as pastas apresentaram reologia e resist?ncia mec?nica adequadas para opera??es de cimenta??o em po?os de petr?leo, al?m de terem suas densidades reduzidas entre 8,40 e 11,89 lb/gal (1,007 e 1,426 g/cm3). Conclui-se que ? poss?vel, sob condi??es atmosf?ricas, obter pastas cimentantes espumadas de baixa densidade com propriedades reol?gicas e mec?nicas satisfat?rias, por meio de incorpora??o de ar e adi??es minerais com efeitos estendedores e estabilizantes. As pastas possuem grande potencial para opera??es de cimenta??o, t?m aplicabilidade em po?os profundos, forma??es de baixo gradiente de fratura e zonas depletadas e trazem redu??es de custo pela diminui??o do consumo de cimento

The subject of this thesis is selected parameters cement mortars with partial replacement of Portland cement diatomaceous earth. This work provides information on the basic properties of diatomaceous earth and its deposits with a focus on deposit in Borovany. From the properties is very important pozzolanic activity due to the high content of amorphous silica of this soil. The main use of diatomaceous earth is in the area filtration and is used widely as a nutritional supplement. In the building industry, diatomite can be applied as an admixture to mortar and concrete, where it can, with its abilities, improve some physical mechanical properties. In the experimental part was diatomaceous earth, in its raw and calcined form, tested as admixture for cement pastes and mortars. The main criterion for evaluating these composites was bulk density, flexural and compressive strength. It was also investigated mineralogical composition, microstructure, freeze–thaw resistance and sulfate resistance.

Made available in DSpace on 2014-12-17T14:08:30Z (GMT). No. of bitstreams: 1 RenataMB.pdf: 1298674 bytes, checksum: 2e9416ef564ec644655637fb323bdd4d (MD5) Previous issue date: 2008-10-06 / Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico / The oil production in Brazil has been increasing each year. Consequently, increasing volumes of water produced are generated with large quantities of contaminants, which brings many problems in disposing of these waters. The concern that the concentrations of contaminants in water produced meet existing laws for disposal of effluents, has been extremely important for the development of different techniques for treatment of water produced. The study of clay minerals as adsorbents of organic contaminants has grown considerably so in order to combine the low cost with the efficiency of environmental preservation and health issues. Thus, this study aims to understand the characteristics of vermiculite clay, sodium bentonite, calcium bentonite and diatomite and evaluate their performance as adsorbents for phenol in the water produced. Through adsorption isotherms it was possible to observe the behavior of these adsorptive clay and diatomite for adsorption of phenol, the main phenolic compound found in water produced. Different concentrations of synthetic solutions of phenol were put in touch with these adsorbents under same conditions of agitation and temperature. The adsorbents were composted adsorptive favorable, but the vermiculite and diatomite showed little capacity for absorption, being suggested for absorbs small concentrations of phenol in the balance isothermal / A produ??o de petr?leo no Brasil vem aumentando a cada ano. Em conseq??ncia, volumes crescentes de ?gua de produ??o s?o gerados com grandes quantidades de contaminantes, o que traz v?rios problemas no descarte dessas ?guas. A preocupa??o para que as concentra??es dos contaminantes da ?gua produzida atendam as legisla??es vigentes para descarte de efluentes, tem sido extremamente importante para o desenvolvimento de diferentes t?cnicas de tratamentos da ?gua produzida. O estudo de argilominerais como adsorventes de contaminantes org?nicos tem crescido de forma consider?vel, a fim de se aliar o baixo custo com a efici?ncia da preserva??o ambiental e sa?de publica. Assim, este trabalho tem como objetivo conhecer as caracter?sticas dos argilominerais vermiculita, bentonita s?dica, bentonita c?lcica e da diatomita e avaliar seus desempenhos como adsorventes de fen?is na ?gua produzida. Atrav?s das isotermas de adsor??o p?de-se abservar os comportamentos adsortivos desses argilominerais e da diatomita para adsor??o do fenol, principal composto fen?lico encontrado na ?gua produzida. Diferentes concentra??es de solu??es sint?ticas de fenol foram postas em contato com estes adsorventes sob agita??o e mesmas condi??es de temperatura. Os adsorventes apresentaram comportamento adsortivo favor?vel, por?m a vermiculita e diatomita apresentaram pequena capacidade de adsor??o, sendo sugeridas para adsorver pequenas concentra??es de fenol no equil?brio isot?rmico

Made available in DSpace on 2014-12-17T14:08:40Z (GMT). No. of bitstreams: 1 VilsineiaAF_DISSERT.pdf: 2438653 bytes, checksum: 9241425e98a35008922b9e1dd051a3af (MD5) Previous issue date: 2010-08-02 / The acceleration of industrial growth in recent decades on all continents aroused the interest of the companies to counter the impacts produced on the environment, spurred primarily by major disasters in the petroleum industry. In this context, the water produced is responsible for the largest volume of effluent from the production and extraction of oil and natural gas. This effluent has in its composition some critical components such as inorganic salts, heavy metals (Fe, Cu, Zn, Pb, Cd, ), presence of oil and chemicals added in the various production processes. In response to impact, have been triggered by research alternative adsorbent materials for water treatment and water produced, in order to removing oils and acids and heavy metals. Many surveys of diatomaceous earth (diatomite) in Brazil involve studies on the physico-chemical, mineral deposits, extraction, processing and applications. The official estimated Jazi are around 2.5 million tonnes, the main located in the states of Bahia (44%) and Rio Grande do Norte (37,4%). Moreover, these two states appear as large offshore producers, earning a prominent role in research of adsorbents such as diatomite for treatment of water produced. Its main applications are as an agent of filtration, adsorption of oils and greases, industrial load and thermal insulator. The objective of this work was the processing and characterization of diatomite diatomaceous earth obtained from the municipality of Maca?ba-RN (known locally as tabatinga) as a low cost regenerative adsorbent for removal of heavy metals in the application of water produced treatment. In this work we adopted a methodology for batch processing, practiced by small businesses located in producing regions of Brazil. The characterization was made by X-ray diffraction (XRD), scanning electron microscopy (SEM) and specific surface area (BET). Research conducted showed that the improvement process used was effective for small volume production of diatomite concentrated. The diatomite obtained was treated by calcination at temperature of 900 oC for 2 hours, with and without fluxing Na2CO3 (4%), according to optimal results in the literature. Column adsorption experiments were conducted to percolation of the in nature, calcined and calcined fluxing diatomites. Effluent was used as a saline solution containing ions of Cu, Zn, Na, Ca and Mg simulating the composition of produced waters in the state of Rio Grande do Norte, Brazil. The breakthrough curves for simultaneous removal of copper ions and zinc as a result, 84.3% for calcined diatomite and diatomite with 97.3 % for fluxing. The calcined fluxing diatomite was more efficient permeability through the bed and removal of copper and zinc ions. The fresh diatomite had trouble with the permeability through the bed under the conditions tested, compared with the other obtained diatomite. The results are presented as promising for application in the petroleum industry / A acelera??o do crescimento industrial nas ?ltimas d?cadas despertou em todos os continentes o interesse das empresas em se contrapor aos impactos produzidos sobre o meio ambiente, incentivadas principalmente pelas grandes cat?strofes ocorridas na ind?stria do petr?leo. Nesse contexto, a ?gua produzida ? respons?vel pelo maior volume de efluentes provenientes de processos de produ??o e extra??o de petr?leo e g?s natural. Este efluente tem em sua composi??o alguns componentes cr?ticos como sais inorg?nicos, metais pesados (Fe, Cu, Zn, Pb, Cd,...), presen?a de ?leo e de produtos qu?micos adicionados nos diversos processos de produ??o. Como resposta a estes problemas foram desencadeadas pesquisas com materiais adsorventes alternativos para o tratamento de ?guas produzidas e ?guas residuais, com a finalidade de remo??o de ?leos e graxos e de metais pesados. Muitas pesquisas feitas com terras de diatom?ceas (diatomita) no Brasil envolvem estudos sobre as caracter?sticas f?sico-qu?micas, jazidas, extra??o, beneficiamento e aplica??es. As jaziadas oficiais estimadas s?o da ordem de 2,5 milh?es de toneladas, sendo as principais localizadas nos estados da Bahia (44%) e Rio Grande do Norte (37,4%). Por outro lado, esses dois estados apresentam-se como grandes produtores de petr?leo em terra, merecendo um destaque importante nas pesquisas de adsorventes como a diatomita para tratamento de ?gua produzida. Suas principais aplica??es s?o como agente de filtra??o, adsor??o de ?leos e graxas, carga industrial e isolante t?rmico. Esse trabalho tem como objetivo o beneficiamento e a caracteriza??o da diatomita do munic?pio de Maca?ba-RN (conhecida na regi?o como tabatinga) como um adsorvente regenerativo de baixo custo para fins de remo??o de metais pesados na aplica??o do tratamento de ?guas produzidas. No presente trabalho adotou-se uma metodologia de beneficiamento por batelada, praticada por pequenas empresas estabelecidas nas regi?es produtoras do Brasil. A caracteriza??o foi feita por difra??o de raios-X (DRX), microscopia eletr?nica de varredura (MEV) e ?rea superficial espec?fica (BET). A investiga??o conduzida mostrou que o processo de beneficiamento utilizado foi eficaz para produ??o em pequena escala de diatomita concentrada. A diatomita obtida foi tratada por calcina??o na temperatura de 900 oC por 2 horas, sem e com fluxante carbonato de s?dio (Na2CO3, 4 %), de acordo com resultados otimizados na literatura. Ensaios de adsor??o em coluna de percola??o foram realizados para as diatomitas in natura, calcinada, e calcinada com fluxante. Como efluente foi utilizado uma solu??o sint?tica contendo ?ons de Cu, Zn, Na, Ca e Mg, simulando a composi??o de ?guas produzidas no estado do Rio Grande do Norte-Brasil. As curvas de ruptura para remo??o simult?nea dos ?ons de cobre e zinco apresentaram como resultados, 84,3 % para diatomita calcinada e 97,3 % para diatomita com fluxante. A diatomita calcinada com fluxante apresentou maior efici?ncia na permeabilidade atrav?s do leito e na remo??o dos ions de cobre e zinco. A diatomita in natura teve dificuldade com a permeabilidade atrav?s do leito nas condi??es testadas, comparada com as outras diatomitas. Os resultados obtidos apresentam-se como promissores para aplica??o na ind?stria do petr?leo

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / Currently there are many studies involving Nanocrystals (NC) incorporated into different types of matrices, including, matrices with porous surface. However, little information is known about the incorporation of NC in Diatomite matrix, and there is a lack of studies on the use of this material. In this context, zinc oxide (ZnO) semiconductor nanoparticles were prepared using two sol-gel methods, microwave and autoclave, at 100 ºC and 180 ºC, respectively. The nanocrystals of ZnO obtained by microwaves were incorporated into a matrix of diatomite (DE) in natura and modified. The modifiers used were APTES (3- aminopropyltriethoxysilane) and MPTS (3-Mercaptopropyltrimetoxysilane) for the study. The material DE/ ZnO, in which ZnO was synthesized with mercaptoethanol (ZnO: ME), was applied for the degradation of Methylene Blue (AM) dye, while ZnO, synthesized with diethyleneglycol (ZnO: DEG), was used for degradation of Rhodamine 6G dye (R6G) by photocatalysis. The results of UV-vis and FTIR spectra show that synthesis carried out by heating under adsorption method is more efficient for the incorporation of ZnO in Diatomite matrix. The FTIR spectra showed that the use of modifiers had no significant influence on the structure. According to the UV-Vis spectra, the DE / ZnO material was successful for application to AM photocatalysis and follows a pseudo-first order kinetics. The ZnO:DEG material used for degradation of R6G obtained higher efficiency due to the wide absorption in the UV-Vis of the photocatalyst material. / Atualmente existem diversos estudos envolvendo Nanocristais (NC) incorporados em matrizes de diferentes tipos, incluindo matrizes com uma superfície porosa. Entretanto, pouco se conhece sobre a incorporação de NC em matriz de Diatomita, além de ser limitado a presença de estudos sobre aplicação desse material. Neste contexto, foram preparadas nanopartículas semicondutoras de óxido de Zinco (ZnO) utilizando dois métodos sol-gel, por micro-ondas e autoclave, numa temperatura de 100 ºC e 180 ºC, respectivamente. Os nanocristais de ZnO obtidos por micro-ondas foram incorporados em matriz de Diatomita (DE) in natura e modificada. Foram utilizados os modificadores APTES (3-Aminopropiltrietoxissilano) e MPTS (3- Mercaptopropiltrimetoxissilano) para o estudo. O material de DE/ZnO, no qual o ZnO foi sintetizado com mercaptoetanol (ZnO:ME), foi aplicado para a degradação do corante Azul de Metileno (AM), enquanto o ZnO, sintetizado com dietilenoglicol (ZnO:DEG), não incorporado foi utilizado para degradação do corante Rodamina 6G (R6G) por fotocatálise. Os resultados de UV-Vis e FTIR mostram que a síntese realizada pelo método de adsorção sob aquecimento é mais eficiente para a incorporação de ZnO na matriz de Diatomita. Os espectros de FTIR mostraram que a utilização de modificadores não exerceu influência significativa na estrutura da DE. Segundo os espectros de UV-Vis, o material de DE/ZnO foi bem-sucedido para aplicação em fotocatálise de AM e segue uma cinética de pseudo-primeira ordem. O material de ZnO:DEG utilizado para degradação de R6G obteve maior eficiência devido a ampla absorção no UV-Vis do material fotocatalisador.

The release of various organic and inorganic pollutants into the environment has been considered a major global problem since it has effects on human health and other forms of life. Among the various methods for treating this problem, heterogeneous photocatalysis using semiconductor nanoparticles has been considered one of the most promising. In this work, nanoparticles of cadmium sulfide anchored onto different diatomite species were synthesized using a fast and simple method. Through the UV/visible spectra, variations in the absorption maxima and spectral shifts to hight wavelengthts were observed with the increase of the reaction time, whereas the XRD data showed the formation of the hexagonal phase for the nanoparticles of cadmium sulfide, while the morphological analyzes showed nanoparticles with an approximately spherical shape. Also, the degradation of the methylene blue dye, ciprofloxacin and the reduction of Cr(VI) to Cr(III) ion reduction were studied via photocatalysis. For the dye degradation tests, studies were carried out under UVA and solar irradiation. It was observed that the photocatalysis process was more effective during irradiation with sunlight. For the photocatalytic tests with chromium and ciprofloxacin, it was noticed that the photocatalysis is much more efficient when compared to the adsorption and photolysis processes, showing a reduction rate around 86% for Cr(VI) to Cr(III), after 210 min of solar irradiation, and a pseudo-first order kinetics, whereas the degradation of ciprofloxacin reached approximately 90% after 180 min of exposure with a secondorder kinetic model. / A presença de diversos poluentes orgânicos e inorgânicos que são lançados diretamente no meio ambiente, tem sido considerada um grande problema mundial, uma vez que traz efeitos à saúde dos seres humanos e a outras formas de vida. Dentre os diversos métodos de tratamento empregados, a fotocatálise heterogênea utilizando nanopartículas semicondutoras tem sido considerada uma das mais promissoras. Neste trabalho, nanopartículas de sulfeto de cádmio ancoradas em diferentes espécies de diatomitas foram sintetizadas com diferentes tempos de síntese, por meio de um método rápido e simples. Através dos espectros no UV/visível, notaram-se variações nos máximos de absorção e descolamentos para maiores comprimentos de onda com o aumento do tempo de reação, já os dados de DRX evidenciaram a formação da fase hexagonal para as nanopartículas de sulfeto de cádmio, enquanto que as análises morfológicas apresentaram nanopartículas de forma aproximadamente esféricas. Adicionalmente, estudos de fotocatálise foram realizados na degradação do corante azul de metileno, do antibiótico ciprofloxacina e na redução dos íons Cr(VI) a Cr(III). Para os testes de degradação do corante foram realizados estudos sob irradiação UVA e solar. Foi observado que o processo de fotocatálise foi mais efetivo durante a irradiação com a luz solar. Já para os testes fotocatalíticos com o Cr(VI) e o ciprofloxacina, notou-se que a fotocatálise é muito mais eficaz quando comparada aos processos de adsorção e fotólise, apresentando uma redução do Cr(VI) a Cr(III) em torno de 86%, após 210 min de irradiação solar,e uma cinética de pseudo-primeira ordem, enquanto que a degradação do ciprofloxacina atingiu aproximadamente 90% após 180 min de exposição solar, apresentando um modelo cinético de segunda ordem. / São Cristóvão, SE

The subject of this thesis are the rheological properties of cement paste with the addition of amorphous silicon dioxide. The basic rheological parameters are that describe the behavior of cement pastes in the fresh state. The work also included rheological tests including measurement principle and method of evaluation. Effect of mineral admixtures with high content of amorphous SiO2 is summarized the available scientific articles. In the experimental part, the effects of impurities with a high content of amorphous SiO2 on the rheological properties of fresh cement paste. It was tested by substitution of up to 10 % by weight of cement in the cement pastes mineral admixtures of different chemical composition, particle size and pozzolanic activity. Flow measurement was measured yield value, viscosity, and flow index. The stability of cement pastes was investigated oscillatory measurements. To complement the behavior pastes in the fresh state was determined by calorimetry. Test results were compared with those determined by reference samples and compared the effect of various ingredients.