Incorporação de resíduo de perfuração em matriz cerâmica: estabilização por solidificação

One of the waste generated during the drilling of oil wells are gravel which are impregnated of drilling fluid. This residue consists of highly toxic chemicals, including toxic metals. This study suggests an alternative process to the treatment of this waste, by incorporating it the form of raw material in the ceramic matrix , and by solidification and stabilize the metals present, Aluminum (Al), Iron (Fe), Manganese (Mn) and Zinc (Zn). The raw materials were characterized by the techniques of X ray fluorescence (FRX), X ray diffraction (DRX), laser granulometry (GL), thermogravimetry (TG) and differential thermal analysis (ADT). To evaluate the percentage of gravel effect the environmental and technological properties were obtained from formulations containing 0, 10 and 20 % by weight of gravel in the ceramic matrix. After sintering at temperatures 1080, 1120 and 1160 °C, the samples were tested for water absorption, the linear shrinkage firing, voltage of rupture and solubility. The results obtained showed that the stabilization by solidification, is a viable alternative to safe disposal of waste drilling. Ceramics products can be used in the manufacture of solid bricks

Estudo da estabilidade térmica de adoçantes naturais e artificiais

Sweeteners provide a pleasant sensation of sweetness that helps the sensory quality of the human diet, can be divided into natural sweeteners such as fructose, galactose, glucose, lactose and sucrose, and articial sweeteners such as aspartame, cyclamate and saccharin. This work aimed to study the thermal stability of natural and artificial sweeteners in atmospheres of nitrogen and syntetic air using thermogravimetry (TG), derivative thermogravimetry (DTG), Differential Thermal Analysis (DTA) and Differential Scanning Calorimetry (DSC). Among the natural sweeteners analyzed showed higher thermal stability for the lactose and sucrose, which showed initial decomposition temperatures near 220 ° C, taking advantage of the lactose has a higher melting point (213 ° C) compared to sucrose (191 ° C). The lower thermal stability was observed for fructose, it has the lowest melting point (122 °C) and the lower initial decomposition temperature (170 °C). Of the artificial sweeteners studied showed higher thermal stability for sodium saccharin, which had the highest melting point (364 ° C) as well as the largest initial decomposition temperature (466 ° C under nitrogen and 435 ° C in air). The lower thermal stability was observed for aspartame, which showed lower initial decomposition temperature (158 ° C under nitrogen and 170 ° C under air). For commercial sweeteners showed higher thermal stability for the sweeteners L and C, which showed initial temperature of thermal decomposition near 220 ° C and melting points near 215 ° C. The lower thermal stability was observed for the sweetener P, which showed initial decomposition temperature at 160 ° C and melting point of 130 °C. Sweeteners B, D, E, I, J, N and O had low thermal stability, with the initial temperature of decomposition starts near 160 °C, probably due to the presence of aspartame, even if they have as the main constituent of the lactose, wich is the most stable of natural sweeteners. According to the results we could also realize that all commercial sweeteners are in its composition by at least a natural sweeteners and are always found in large proportions, and lactose is the main constituent of 60% of the total recorded

Estudo termoanalítico da perlita hidrofobizada com óleo de linhaça

In this work, expanded perlite, a mineral clay, consisting of SiO2 and Al2O3 in the proportions of 72.1 and 18.5%, respectively, was used as an adsorbent for oil in its pure expanded form as well as hydrofobized with linseed oil. Thermogravimetry (TG), Derivative Thermogravimetry (DTG) and Differential Thermal Analysis (DTA) were used to study the thermal behavior and quantify the percent adsorption of perlite in differents processes comparing the results with the ones obtained using Gravimetric Analysis. In the process of hydrophobization with linseed oil granulometric fractions > 20, 20-32 and 32-60 mesh were used and adsorption tests with crude oil were performed in triplicate at room temperature. The results obtained by TG/DTG in dynamic atmosphere of air showed mass losses in a single step for the expanded perlite with pure adsorbed oil, indicating that the adsorption of oil was limited and that the particle size did not in this process. Linseed oil has performed well as an agent of hydrophobized perlite (32 to 60 mesh) indicating a maximum percentage of 59.9% and 68.6% the linseed with a fraction range from considering the data obtained by thermogravimetry and Gravimetry, respectively. The adsorption of oil in the expanded perlite and hydrofobized pure perlite with linseed oil did not produce good results, characterizing an increase of 0.5 to 4.6% in pure perlite and 3.3% in hydrofobized perlite with granulometric 32 to 60 mesh

Avaliação da estabilidade térmica e oxidativa do biodiesel de algodão e do efeito da adição de antioxidantes (α-tocoferol e BHT)

This work aims to study the effects of adding antioxidants, such as, α- tocopherol and BHT on the thermal and oxidative stability of biodiesel from cottonseed (B100). The Biodiesel was obtained through the methylical and ethylical routes. The main physical and chemical properties of cotton seed oil and the B100 were determined and characterized by FTIR and GC. The study of the efficiency of antioxidants, mentioned above, in concentrations of 200, 500, 1000, 1500, 2000ppm, to thermal and oxidative stability, was achieved by Thermogravimetry (TG), Differential Thermal Analysis (DTA), Differential Scanning Calorimetry (DSC), Differential Scanning Calorimetry - Hi-Pressure (P-DSC) and Rancimat. The Biodiesel obtained are within the specifications laid down by Resolution of ANP No7/2008. The results of TG curves show that the addition of both antioxidants, even in the lowest concentration, increases the thermal stability of Biodieseis. Through the DTA and DSC it was possible to study the physical and chemical transitions occurred in the process of volatilization and decomposition of the material under study. The initial time (OT) and temperature (Tp) of oxidation were determined through the P-DSC curve and they showed that the α-tocopherol has a pro-oxidant behavior for some high concentrations. The BHT showed better results than the α-tocopherol, with regard to the resistance to oxidation

Complexos metálicos de cobalto, níquel e cobre com a Pirazina-2-carboxamida e 4- hidrazida ácida piridincarboxílica: síntese e caracterização

This work involved the synthesis, characterization and proposing the molecular structure of coordination compounds involving ligands pyrazine-2-carboxamide (PZA) and 4- hydrazide acidic pyridine carboxylic (INH) and metals of the first transition series (M = Co2+, Ni2+ and Cu2+). For the characterization of the compounds used were analytical techniques such as infrared absorption spectroscopy average (FT-IR) molar conductivity measurements, CHN elemental analysis, EDTA Complexometric, measurement of melting point, X-ray diffraction by powder method, Thermogravimetry (TG) and Differential Thermal Analysis (DTA) and Simultaneous Differential Scanning Calorimetry (DSC). The absorption spectra in the infrared region suggested that the ligand coordination to the metal center occurs through the carbonyl oxygen atom and nitrogen alpha pyrazine ring to those complexes formed with PZA. For INH complexes with metal-ligand coordination is through the carbonyl oxygen and nitrogen of the terminal hydrazide grouping. The conductivity measurements of the complexes in aqueous solution they suggest to all behavior of the type 1:2 electrolytes, and conduct of non-electrolytes in acetonitrile. The results obtained by CHN elemental analysis and EDTA Complexometric allowed to infer the stoichiometry of the compounds synthesized. For all of the complexes obtained was possible to record the melting points, neither of which melted near the melting temperature of the free ligands. The X-ray diffraction showed that the complexes of pyrazinamide exhibited diffraction lines, suggesting that these compounds are crystalline, while compounds of isoniazid, with the exception of cobalt, exhibited diffraction lines, indicating that they are crystalline. The results from the TG-DTA and DSC allowed information regarding the dehydration and thermal decomposition of these complexes

Desenvolvimento de uma rota química alternativa de síntese de SrCo0,8Fe0,2O3- e LaNi0,3Co0,7O3- para aplicação na reação de oxidação do CO

This thesis focuses on the coprecipitation synthesis method for preparation of ceramic materials with perovskite structure, their characterization and application as catalytic material in the reaction of converting CO to CO2 developing a methodological alternative route of synthesis from the middle via oxalate coprecipitation material SrCo0,8Fe0,2O3-d. In order to check the influence of this method, it was also synthesized using a combined citrate - EDTA complexing method. The material was characterized by: X-ray diffraction (XRD), Rietveld refinement method, thermogravimetry and differential thermo analysis (TG / DTA), scanning (SEM) and transmission (TEM) electron microscopy, particle size distribution and surface analysis method BET. Both methods led to post-phase synthesis, with pH as a relevant parameter. The synthesis based on the method via oxalate coprecipitation among particles led to the crystalline phase as those obtained using a combined citrate - EDTA complexing method under the same conditions of heat treatment. The nature of the reagent used via oxalate coprecipitation method produced a material with approximately 80 % lower than the average size of crystallites. Moreover, the via oxalate coprecipitation method precursors obtained in the solid state at low temperature (~ 26 oC), shorter synthesis, greater thermal stability and a higher yield of around 90-95 %, maintaining the same order of magnitude the crystallite size that the combined citrate - EDTA complexing method. For purposes of comparing the catalytic properties of the material was also synthesized by the using a combined citrate - EDTA complexing method. The evaluation of catalytic materials SrCo0,8Fe0,2O3-d LaNi0,3Co0,7O3-d was accompanied on the oxidation of CO to CO2 using a stainless steel tubular reactor in the temperature range of 75-300 oC. The conversion CO gas was evaluated in both materials on the results shaved that the firm conversion was loves for the material LaNi0,3Co0,7O3-d

Preparação e caracterização do complexo sólido de estanho(II)-EDTA e influência do tratamento térmico sobre a morfologia do resíduo SnO2

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Obtenção da fase peroviskita via microemulsão

Pequenas partículas de fase peroviskita de BaMnO3 foram preparadas por dois métodos: a rota da coprecipitação convencional (RCC) e o método convencional de microemulsão (MCM). As técnicas instrumentais utilizadas para caracterizar as amostras foram: microscopia eletrônica de varredura (SEM), difratometria de raios X (XRD), termogravimetria (TG) e análise térmica diferencial (DTA). A síntese de materiais em sistemas coloidais auto-organizados tem por objetivo aumentar a homogeneidade de tamanho e forma das partículas. Nos últimos anos aumentou a busca por materiais mais uniformes visando o aperfeiçoamento da microestrutura. A rota de microemulsão é um método alternativo para a síntese de materiais porque permite o controle da relação entre as concentrações de água e do tensoativo, (w), o qual controla o tamanho das gotículas de microemulsão denominadas microreatores. Peroviskita pura obtida de microemulsão forma-se em temperatura menor do que a fase precipitada, e resulta.em partículas com distribuição de tamanho mais adequada, de aproximadamente 0,1 mm de diâmetro comparado com a média de 0,5 mm das partículas coprecipitadas.

Sintering and crystallite growth of nanocrystalline copper doped tin oxide

The effect of Cu2+ contents and of firing temperature on sintering and crystallite growth of nanocrystalline SnO2 xerogels was analyzed by thermoanalysis (mass loss (TG), linear shrinkage, and differential thermal analysis (DTA)), X-ray powder diffraction (XRPD), and EXAFS (extended X-ray absorption fine structures) measurements. Samples were prepared by two methods: (a) coprecipitation of a colloidal suspension from aqueous solution containing both Sn(IV) and Cu(II) ions and (b) grafting copper(II) species on the surface of tin pride gel. The thermoanalysis has shown that the shrinkage associated with the mass loss decreases by increasing the amount of copper. The EXAFS measurements carried out at the Cu K edge have evidenced the presence of copper in substitutional solid solution for the dried xerogel prepared with 0.7 mol % of copper, while for higher concentration of doping, copper has been observed also at the external surface of crystallites. The solid solution is metastable and copper migrates toward the surface during firing. The XRPD and DTA results have shown a recrystallization process near 320 degrees C, which leads to crystallite growth. The presence of copper segregated near the crystallite surface controls its growth.

Influence of pH and precipitation temperature on the structural characteristics of aluminium hydroxides prepared form nitrate aqueous solutions

Aluminium Hydroxides were precipitated from Aluminium Nitrate and Ammonium Hydroxide, at the temperatures 64 degrees C (hot) and 25 degrees C (cold), under the pH conditions 5, 7 and 9. The samples were characterized by X-Ray Diffraction (XRD) and Differential Thermal Analysis (DTA). The hydroxide precipitated at pH 9 and 64 degrees C is built up by pseudoboehmite and a minor share of others apparently amorphous hydroxides. The crystallinity of the hot yielded pseudoboehmite diminishes with the pH. The crystallite size was evaluated as about 40 Angstrom for the best crystallized sample. The cold precipitated product is apparently composed by amorphous or very poorly crystallized hydroxides. Upon heating, the cold precipitated hydroxides, and the low pH and hot precipitated hydroxide, release their structural water before the occurrence, about 430 degrees C, of the transition of the pseudoboehmite to gamma-alumina, and exhibit a shifting (towards low temperature side) and a broadening in the peak of the transition to alpha-alumina, which occurs at 1200 degrees C in the pseudoboehmite pattern. The yielded pseudo-boehmite peptized by HNO3, addition and gelified by evaporation in a critical concentration approximately 0.17 gcm(-3).

Thermoanalytical study of some anti-inflammatory analgesic agents

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Caracterização e estudo do comportamento térmico de lodo proveniente da indústria sucroalcooleira

Pós-graduação em Química - IBILCE

Caracterização térmica de sacarose de cana-de-açúcar: amostras de padrão de referência, comercial e purificada

Pós-graduação em Química - IBILCE

Estudo do comportamento térmico de hidrocarbonetos policíclicos aromáticos (HPAs) em fuligem de cana-de-açúcar

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Estudo da atividade biológica de compostos de paládio (II)

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)