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Dissertations |
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ELISA GABRIELA COSTA GOUVEIA
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SYNTHESIS AND CATALYTIC EVALUATION OF MORDENITE ZEOLITE WITH HIERARCHICAL PORE SYSTEM IN THE PRESENCE OF MONOSODIUM GLUTAMATE
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Advisor : ANTONIO OSIMAR SOUSA DA SILVA
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COMMITTEE MEMBERS :
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ANTONIO OSIMAR SOUSA DA SILVA
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BRUNO JOSÉ BARROS DA SILVA
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LUCAS MEILI
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PAULO HENRIQUE LEITE QUINTELA
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Data: May 31, 2023
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Show Abstract
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Mordenite is a synthetic zeolite with a relatively high Si/Al ratio, with values between 5 and 20, which has potential in the field of catalysis in different industrial processes, such as hydrocracking, hydroisomerization and alkylation reactions, due to its high acidity and thermal stability. However, mordenite is generally considered a one-dimensional pore system, which causes diffusional limitations to the active sites. To overcome this issue, introducing mesopores is a facile approach. The present work promoted the study of a new approach to the synthesis of the mordenite zeolite using monosodium glutamate via hydrothermal method at 170 ºC in an oven with agitation of 60 rpm at different crystallization times. Zeolites were characterized by X-ray diffraction, X-ray energy dispersion spectroscopy, scanning electron microscopy, thermogravimetric analysis, adsorption/desorption of nitrogen and temperature-programmed desorption of ammonia. The selected samples were evaluated in the n-hexane and ultra-high molecular weight polyethylene cracking reactions. The materials were obtained with high crystallinity, with the increment in the Si/Al ratio and decrease in the density of acid sites with the increase in the monosodium glutamate content. Thermal analysis revealed complete removal of the amino acid salt from the zeolite structure after washing. The micrographs showed crystal clusters of <10 μm with variable geometry and partial disaggregation of the crystals with the use of glutamate. Nitrogen adsorption/desorption measurements simultaneously indicated an improvement in micro and mesoporosity for the materials synthesized with monosodium glutamate/alumina ratio of 2 and 4, with an increase of 8% and up to 33% in the volume of micropores and mesopores, respectively. The catalytic tests of nhexane cracking resulted in a higher tendency for the formation of olefins. Lower values for the apparent activation energy were obtained in the thermocatalytic degradation of ultra-high molecular weight polyethylene in the presence of zeolites, with a percentage reduction ranging from 19 to 36% compared to pure polymer
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2
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TAINÁ DE BORBOREMA HITA
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DEVELOPMENT OF A CARBON TETRACHLORIDE INFERENTIAL MODEL ON A VCM PRODUCTION UNIT
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Advisor : JOAO INACIO SOLETTI
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COMMITTEE MEMBERS :
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JOAO INACIO SOLETTI
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JOAO BATISTA MAIA ROCHA NETO
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RODOLFO JUNQUEIRA BRANDAO
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SANDRA HELENA VIEIRA DE CARVALHO
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JULIO INACIO HOLANDA TAVARES NETO
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Data: Jun 29, 2023
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Show Abstract
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In the production of Vinyl Monochloride (MVC) the 1,2-Dichloroethane (1,2-DCE) must undergo a purification process, as the 1,2-DCE cracking process is highly susceptible to inhibition and deposition by traces of impurities. It must have a purity greater than 99.5 %wt/wt. One of the impurities with the greatest inhibiting capacity in the cracking reaction is the presence of Carbon Tetrachloride (CCl4). Therefore, having an online CCl4 measurement at the output of the 1,2-DCE purification process allows for greater control of the cracking reaction, avoids production losses, allows for an optimization of the process, in addition to generating a reduction in the campaign time of the cracking ovens. The importance of this real-time analysis, the need to control this impurity and the difficulties in maintaining the analytical instruments motivated the work of developing a model for inferring the analysis. The partial results obtained indicate paths of input variables for inference of the composition of CCl4, in addition to a viable virtual analyzer model so that these results can be included in the process control.
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3
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4
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WANDERSON DOS SANTOS CARNEIRO
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AGGLOMERATION PROCESS OF THE CYANOBACTERIUM Spirulina platensis IN FLUIDIZED BED TOWARDS FOOD APPLICATION
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Advisor : CARLOS EDUARDO DE FARIAS SILVA
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COMMITTEE MEMBERS :
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ANA KARLA DE SOUZA ABUD
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CARLOS EDUARDO DE FARIAS SILVA
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KACIANE ANDREOLA
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RODOLFO JUNQUEIRA BRANDAO
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Data: Jul 31, 2023
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Show Abstract
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In view of the intense increase in research with a perspective for the development of food sources that are conventional and that are able to meet the demand of the population, the cyanobacterium Spirulina platensis has stood out due to its nutritional properties, being a source of proteins, vitamins, minerals, pigments, between others. However, this cyanobacteria in powder form has fine particles, which leads to undesirable physical properties, such as low dispersion in liquids and poor flow, in addition to losses of fines in handling, limiting its industrial use. The fluidized bed agglomeration process is used to increase the size of fine particles, improving physical properties. Thus, the objective of this work was to study the agglomeration process of the cyanobacteria Spirulina platensis in a fluidized bed, in order to improve the physical properties of the powder, as well as to evaluate the quality of the agglomerated powder. The process study was carried out using a 22 full factorial design in order to identify possible improvements in terms of process, product quality and influence of operational variables on process performance. The planning tests were carried out varying the operating conditions of fluidization air temperature (65 °C - 85 °C) and binder solution flow rate (1,5 mL/min - 3,5 mL/min), which was a 30% maltodextrin solution. The responses evaluated were process yield, humidity, average particle size (D50), fluidity, wetting time and water activity. The information studied revealed a powder that showed particle growth, moisture below 15%, powders with flow characterized as reasonable, improvement in wetting time and water activity below the value of 0,65. The powders were also characterized according to the color parameters, obtaining a decrease in the L* and b* parameters and an increase in the a* parameter and finally, characterized in the centesimal composition. The results revealed that the best process conditions were obtained using a fluidization air temperature of 85 °C and a binder atomization flow rate of 2,5 mL/min and a fluidization air temperature of 75 °C and an atomization flow rate of binder of 2,0 mL/min, making it possible under these conditions to obtain yields above 50%, as well as an agglomerated powder with high protein content with values above 56%, low moisture content (5,46% for the condition with temperature of 85°C and 6,51%-7,4% for the condition with a temperature of 75°C) which are within the tolerable limit established by ANVISA, good fluidity, increase in the average particle size by 3,5 times and improvement in wetting time.
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5
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LARISSA FARIAS QUEIROZ
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Feasibility of using construction and demolition waste as adsorbents for application in the treatment of contaminated water.
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Advisor : LUCAS MEILI
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COMMITTEE MEMBERS :
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DANIEL PINTO FERNANDES
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DANILO HENRIQUE DA SILVA SANTOS
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LUCAS MEILI
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POLLYANNA VANESSA DOS SANTOS LINS
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RODOLFO JUNQUEIRA BRANDAO
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Data: Aug 10, 2023
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Show Abstract
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The growth of urbanization and, consequently, the construction industry plays an important role in the global economy. However, this sector is responsible for significant environmental impacts, mainly related to the production of large quantities of solid waste, which, combined with issues arising from excessive consumption of natural raw materials, pose significant challenges for global sustainable development. To address these challenges, the development of processes that enable recycling and/or reutilization of these waste materials, considered the most environmentally friendly alternatives, has been the main focus of study in this field. In this context, this work aims to evaluate the potential use of construction and demolition waste (CDW) as adsorbent material in the treatment of contaminated water. To achieve this, a bibliometric study and adsorption experiments were conducted. The main results of the bibliometric analysis indicate a significant growth in interest in the studied topic worldwide in recent years. A total of 70 documents from 31 countries were retrieved, with China (26) standing out as the most productive country. The keyword network used by the authors indicates that the recovered publications mainly address aspects related to the acquisition, treatment, and utilization of construction and demolition waste (CDW) for the removal of various pollutants. The synthesis route and the combination with other materials and/or techniques were also depicted in the retrieved works. These results constitute an important tool for guiding future research on the subject. In the adsorption tests, the material was chemically and thermally treated, and its adsorption efficiency was tested. The material with the best performance was then characterized (FTIR, XRD, SEM, TG, BET, and EDX) and used in the adsorption experiments. The kinetic tests showed an adsorption rate of 0.065 mg/min during the first 120 minutes, which then decreased over time, reaching 0.026 mg/min until reaching adsorption equilibrium after 5 hours. The experimental data obtained showed a better fit to the Elovich model with an adsorption capacity of 8 mg/g. For the isotherms, the Sips model provided the best fit. Thermodynamic studies indicated that the reaction is spontaneous, and the process is exothermic. Through the regeneration tests, a maximum regeneration efficiency of approximately 65% was achieved when using 100 mmol/L of H2O2 in the presence of Fe2+ for a period of 4 hours. These results demonstrate the high potential of using CDW as adsorbent material.
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6
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KÉSSYA JAYNE GONÇALVES DE ARAÚJO
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Advisor : LEONARDO MENDONCA TENORIO DE MAGALHAES OLIVEIRA
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COMMITTEE MEMBERS :
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JOSE LEANDRO DA SILVA DUARTE
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LEONARDO MENDONCA TENORIO DE MAGALHAES OLIVEIRA
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LIVIA MARIA DE OLIVEIRA RIBEIRO
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SAMUEL TEIXEIRA DE SOUZA
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VANDERSON BARBOSA BERNARDO
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Data: Nov 17, 2023
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Show Abstract
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Thesis |
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1
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RAISA AMORIM SACRAMENTO
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MESOPOROUS SILICA MATERIALS TEMPLATED WITH SUCROSE FOR CO2 ADSORPTION
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Advisor : ANTONIO OSIMAR SOUSA DA SILVA
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COMMITTEE MEMBERS :
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ANTONIO OSIMAR SOUSA DA SILVA
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JOAO INACIO SOLETTI
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LEONARDO MENDONCA TENORIO DE MAGALHAES OLIVEIRA
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JOHNNATAN DUARTE DE FREITAS
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PAULO HENRIQUE LEITE QUINTELA
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Data: Mar 30, 2023
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Show Abstract
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The capture and storage of carbon dioxide (CO2) has been indicated as an effective strategy to reduce the emissions of this gas with the greatest impact on the greenhouse effect. Several studies have focused on the application of mesoporous silica materials in CO2 adsorption processes. And SBA-15 has stood out as a CO2 capture capture agent to its large pore volume and diameter and high thermal and hydrothermal performance. However, the synthesis of these materials still has a high cost due to the complexity in the processing to obtain tetraethylorthosilicate and the use of synthetic surfactants to model these materials. The objective of the present work was the synthesis of mesoporous silica materials, using sodium silicate (Na2SiO3) as a silica source and sucrose as a structure modeler, for the adsorption of CO2. The materials were synthesized with sucrose in different molar ratio (0, 0,3, 1, 2 e 3) in relation to silica (SiO2). The structures of mesoporous were prepared and characterized by thermogravimetric analysis (TG/DTG) and nitrogen adsorption at -196°C, confirming the formation of a mesoporous silica structure and showing that increasing sucrose composition during synthesis resulted in improved properties and textures of these materials. The samples prepared with higher sucrose composition obtained the best results obtained the best results for surface area, 322 and 343 m2 ∙g-1, and pore diameter, 7 and 9 nm, respectively. The results obtained in the adsorption tests found that the structures synthesized with sucrose correlated better with the Elovich Kinetic model, indicating that chemisorption is a rate-limiting step in the CO2 adsorption process of these materials. The adsorbents prepared with higher sucrose composition showed better adsorption capacities, 44.37 and 47.81 mg.g-1, respectively, reaching adsorption capacity superior to other mesoporous silica structures.
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2
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RAFAELA GABRIEL
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STUDY OF THE EFFECTS OF STIRRING AND MIXING IN THE SYNTHESIS PROCESS OF LAMELLAR DOUBLE HYDROXIDES (LDHs)
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Advisor : LUCAS MEILI
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COMMITTEE MEMBERS :
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GABRIELA SILVEIRA DA ROSA
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JOAO INACIO SOLETTI
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KLEBER JEAN LEITE DOS SANTOS
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LIVIA MARIA DE OLIVEIRA RIBEIRO
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LUCAS MEILI
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RODOLFO JUNQUEIRA BRANDAO
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Data: Mar 31, 2023
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Show Abstract
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The stirring and mixing process comprises the determination of mechanical parameters and sizing of the reactors, such as: stirring speed, types of impellers, baffles, among others. Such characteristics are crucial in promoting mass and energy transfer to the system and are associated with tank configurations. Process variables are commonly studied to define design and scale-up criteria for complex mixtures, such as processes that crystallize. The synthesis by coprecipitation of lamellar double hydroxides (HDLs), clays belonging to the class of mineral nanoparticles, is governed by the steps of nucleation and crystal growth, directly associated with the efficiency of the mixing and dispersion process of the reagents. However, in the literature there is no specific study on these effects and what they imply for the formation of LDH. Due to the lack of this information, this work proposes the study of mechanical parameters (process variables) in a batch reactor, for the synthesis of LDH by the coprecipitation method at variable pH. The study was carried out by evaluating the influence of the following process variables: stirring speed (200, 600 and 1000 rpm), stirring time (2, 10 and 18 h) and presence or absence of baffles, in response to the planning the structural and morphological characteristics of LDH. The evaluation of parameters should serve as a basis for improving the characteristics of LDH such as crystallinity, porosity and phase purity. In this sense, efforts are directed towards improving synthesis processes and optimizing the production of LDH and ensuring robustness and safety in industrial applications. In general terms, mechanical variables had an influence on the structural characteristics of HDLs, with significant changes in viscosity, density, yield (23.15 - 34.61%), crystallinity and crystallite size (70.99 - 174.79 nm).
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3
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FRANCINE PIMENTEL DE ANDRADE
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Use of microalga and filamentous fungi in the treatment of industrial effluents (whey and petroleum produced water)
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Advisor : CARLOS EDUARDO DE FARIAS SILVA
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COMMITTEE MEMBERS :
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ANA KARLA DE SOUZA ABUD
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CARLOS EDUARDO DE FARIAS SILVA
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CRISTINA FERRAZ SILVA
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JOAO INACIO SOLETTI
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RENATA MARIA ROSAS GARCIA ALMEIDA
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Data: May 9, 2023
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Show Abstract
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This work aimed to obtain information regarding the use of microalgae and the co-cultivation of microalgae with other microorganisms (bacteria, filamentous fungi and yeasts) in the treatment of wastewater, specifically the dairy wastewater, and petroleum produced water. For this, a literature review regarding open system cultivation revealed information about the ability to remove contaminants (mainly Chemical Oxygen Demand (COD), Total Nitrogen (TN) and Total Phosphorus (TP)) present in industrial effluents by microalgae and their consortia with other microbial groups. Microalgae-bacteria consortia are used mainly due to the great capacity to remove organic matter from bacteria and better assimilation of nitrogen and phosphorus by microalgae. On the other hand, lines of research using the consortium of microalgae with yeasts and filamentous fungi have gained attention, first because yeasts can accumulate a high lipid content, as well as microalgae, and can therefore be used, for example, in the production of biodiesel, and in the case of filamentous fungi to increase the capacity of effluent treatment containing molecules complex organic compounds (the metabolic power of fungi is superior to that of microalgae) and helps in the process of harvesting microalgal biomass. But it is recognized that the biotechnological applications for these two groups can be expanded, therefore, research is necessary. The type of bioreactor and mode of operation significantly influence the effluent treatment process using microalgae. Thus, a review of the operating modes showed that batch and fed-batch cultivations present lower risks of contamination, while the continuous and semi-continuous modes have higher productivity rates. Combining the use of effluents, reactors and mode of operation in conjoint with the nutritional and environmental requirements, can reach removal rates for COD, nitrogen and phosphorus greater than 90%. After, a kinetic model was developed to describe simultaneous removal of organic carbon, nitrogen and phosphorus, and microbial growth in wastewater treatment using microalgae, applying the n-order model for contaminant consumption, Monod (a limiting substrate) and Silva and Cerqueira (multiple substrates) for microbial growth. The results demonstrate the ability of these models to predict the treatment behavior of different industrial effluents. Additionally, an experimental procedure was performed, in which the cultivation of the microalgae Tetradesmus obliquus in the treatment of whey in open ponds was evaluated through experiments carried out at different organic loads (0.5-4% v/v) and light intensities (25- 200 µmol m-2 s-1). It was possible to efficiently remove COD, nitrogen and phosphorus with rates greater than 80% at higher light intensities (25-200 µmol m-2 s-1) in all analysed organic loads, with emphasis on the lower ones (0.5 and 1% v/v) because they have a final concentration of contaminants in accordance with the legislation. In addition, a literature review on the biological treatment of oil produced water was carried out, and it was shown that there are few published works when compared to other effluents, mainly due to the characteristic of this wastewater, such as xenobiotic substances, high oil and grease content, and high salinity. In this sense, physical and chemical processes are more applied, although they are more effective when the treated water is used for reinjection in the wells, but due to the high salinity and the presence of toxic compounds, it is suggested the bioremediation of the effluent when the water produced it can be used for other noble purposes such as irrigation. Studies using bacteria, microalgae, filamentous fungi and yeasts were found, the first one being the most prominent, but showing the potential and need for further studies with other microbial groups. In this sense, experiments were conducted to treat produced water in a bubble column reactor using the co-culture of microalgae (Tetradesmus obliquus) and filamentous fungi (Aspergillus niger, Penicillium oxalicum and Cunninghamella echinulata). The species C. echinulata achieved higher TOG removal rates (90-95%), initially with 312-2500 mg L-1, being more efficient than microalgae for this parameter. At different salinity concentrations (5-50 g L-1), and T. obliquus remained alive up to 25 g L-1, while the fungus C. echinulata grew at all salinity concentrations and removed TOG at rates between (80-95%). Finally, the co-culture of T. obliquus-C. echinulata removed up to 63.4 and 36.58% of nitrogen and phosphorus, with initial concentrations between 50-150 and 30 mg L-1, respectively.
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4
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TARSILA SANTOS DA SILVA
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SYNTHESIS, CHARACTERIZATION AND APPLICATION OF LAYERED DOUBLE HYDROXIDES FROM ALUMINUM WASTE
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Advisor : SIMONI MARGARETI PLENTZ MENEGHETTI
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COMMITTEE MEMBERS :
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ANTONIO OSIMAR SOUSA DA SILVA
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LIVIA MARIA DE OLIVEIRA RIBEIRO
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LUCAS MEILI
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PAMELA MARGARITA SEPULVEDA
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PAULO ANSELMO ZIANI SUAREZ
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SIMONI MARGARETI PLENTZ MENEGHETTI
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Data: May 25, 2023
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Show Abstract
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One of the most important and strategic essential industries is the aluminum production. Aluminum is the third most abundant element on Earth and the second most used metal after iron. Inappropriate recycling and reuse of aluminum waste, large amounts of these materials are disposed of in landfills, facing health, ecology and safety risks due to their toxicity and high flammability. These issues are driving the development of new cost-effective and ecologically sound methods of reusing aluminum waste. The production of Lamellar Double Hydroxides (LDH) using aluminum residues can be achieved through the leaching of Al3 + ions, in the form of hydroxide, followed by reaction with the divalent ions. Aluminum ions can be extracted by dissolving the residue in an alkaline or acidic medium. This work had as objective the synthesis and characterization of LDHs obtained from the residues of aluminum frames. The syntheses of LDHs were carried out by the co-treatment and hydrothermal treatment methods, maintaining a 3:1 ratio of Mg/Al. Infrared absorption spectroscopy (FT-IR), X-ray diffraction (XRD), thermogravimetry (TGA) and specific surface area (BET). The FT-IR wavelengths referring to the synthesized HDL chemical groups did not diverge, the input being commercial aluminum hydroxide or coming from aluminum frames. The X-ray diffractograms of LDHs with indicated peaks characteristic of materials of the hydrotalcite type, which are more intense diffraction elements for the LDH synthesized from the hydrothermal treatment. From the Scherrer equation, an increase in the crystallite size was observed with the increase in the synthesis temperature. A thermogravimetric analysis proceeds by the loss of water adsorbed between the layers, followed by the dehydroxylation of the coverslips with water release, different values in the loss of mass for the studied synthetic conditions. The LDHs obtained showed type IV and the presence of type H3 hysteresis, which evidences the existence of mesoporous structures. The surface area and pore diameter range from 27.66 m2/g to 96.08 m2/g and 36 Ǻ to 39 Ǻ, respectively. From the results obtained, it is possible to verify that LDH produced from aluminum waste has potential for future applications in the areas of catalysis and adsorption.
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5
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TACIANA CARNEIRO CHAVES
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Anaerobic co-digestion of vinasse and sugarcane molasses for H2 production
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Advisor : RENATA MARIA ROSAS GARCIA ALMEIDA
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COMMITTEE MEMBERS :
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CARLOS EDUARDO DE FARIAS SILVA
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DAYANA DE GUSMAO COELHO
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EDUARDO LUCENA CAVALCANTE DE AMORIM
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FERNANDA SANTANA PEITER
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LUCAS MEILI
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RENATA MARIA ROSAS GARCIA ALMEIDA
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Data: Oct 23, 2023
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Show Abstract
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The use of industrial waste containing abundant carbohydrates, lipids and proteins represents an alternative source of renewable energy that is gaining prominence today. Waste from the sugar and alcohol agroindustry, such as vinasse and sugar cane molasses, are rich in organic matter and, therefore, when subjected to the anaerobic digestion process, they can be converted into hydrogen, organic acids and methane. By maintaining control of specific operational parameters, it is possible to inhibit the formation of methane and favor the production of only H2 and/or acids. In this context, the objective of this study was to use the co-fermentation of vinasse and molasses to produce hydrogen. To this end, in a first phase (F1), based on the experimental design of the Simplex Lattice mixture, batch tests were carried out to evaluate the synergistic and/or antagonistic effects of vinasse (V) and molasses (M) in search of the best percentage composition of substrates (V100/M0 = R1, V75/M25 = R2, V50/M50 = R3, V25/M75 = R4, V0/M100 = R5) that resulted in maximum H2 production and used the highest possible percentage of vinasse, for This is the substrate that in the sugar and alcohol industry is the final residue of the process and has a great environmental impact. Based on the best condition observed in F1, a second phase (F2) was implemented, also in batch reactors. The influence of the initial concentration in terms of chemical oxygen demand (COD 6 and 9 g/L), temperature (T between 35 and 45 °C) and initial pH (5.5 and 6.5) were tested based on in a complete factorial design (23). At this stage, five response variables were evaluated, three of which were obtained from adjusting the data to the Modified Gompertz model (maximum production potential - P, maximum production rate - Rm and duration of the lag phase - ʎ). The other dependent variables were the volumetric production rate (VHPRDQOapl) and the volumetric hydrogen yield (VHYDQOapl). In F1, the results showed that the use of vinasse at 75% or more caused instability in H2 production. Maximum values of 595.63 mL-H2/g-DQOapl and 50.63 mL-H2/(g-DQOapl.d) were obtained, both verified in the V50/M50 condition, which, according to the Tukey test, these were results statistically similar to those observed at V25/M75 and V0/M100. Vinasse and molasses interacted synergistically in the mixtures. Highly significant (p ≤ 0.05) quadratic models with good fits were obtained for yield (R2 = 0.98) and H2 production rate (R2 = 0.92). In F2, with the initial composition of the feed fixed at 50% of each substrate, the maximum values of P (925.05 mL-H2), Rm (1.24 mL-H2/h), VHYDQOapl (1.56 L-H2/g-DQOapl) and VHPRDQOapl (54.98 mL-H2/g-DQOapl/d) in the condition of lower temperature and higher COD and pH. The lag phase lasted from 0.00 hours (6 g/L, pH 6.5 and 35 °C) to 36.30 hours (9 g/L, pH 5.5 and 45 °C). pH was the most influential factor with a positive effect on the response variables, except under ʎ, which presented temperature as the most influential factor and pH with a negative effect. Temperature revealed a negative influential effect on responses, except under ʎ. The effect of COD was significantly positive for P, Rm and ʎ, but had negligible influence in relation to VHY and VHPR. Significant and well-adjusted linear models were obtained to relate the COD, pH and T factors with each response, all with R2 > 0.9.
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6
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RODRIGO DE OLIVEIRA FARIAS
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COCONUT STALK PYROLYSIS FOR THE PRODUCTION OF PHENOLS AND ACTIVATED CARBON
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Advisor : JOAO INACIO SOLETTI
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COMMITTEE MEMBERS :
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ANTONIO MARTINS DE OLIVEIRA JUNIOR
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JOAO INACIO SOLETTI
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LAIZA CANIELAS KRAUSE
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MOZART DALTRO BISPO
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RODOLFO JUNQUEIRA BRANDAO
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SANDRA HELENA VIEIRA DE CARVALHO
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Data: Oct 31, 2023
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Show Abstract
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The coconut crop has great economic relevance in Asia-Pacific and Brazil. Due to the high amount of fibers and waste generated, researchers have given special attention to adding value to these materials. Among them, some biomasses such as coconut inflorescence have been little researched. Using pyrolysis technology, coconut crop residues can be transformed into both liquid (bio-oil) and solid (coal) fuels. In the case of coal, it can also be used as an adsorbent. In this work, coconut inflorescence biomasses were pyrolyzed. Effects of pyrolysis temperature (290–710 °C) and heating rate (2–58 °C∙min-1) were evaluated. A rotatable central composite design was developed to identify interaction effects of these variables. Yield of products (biochar, gas and bio-oil) and concentration of phenol in bio-oil (Cphenol) were the response variables investigated. Response surface methodology was used to obtain optimal phenol concentration. Furthermore, the biomass and bio-oil were characterized by analysis of thermogravimetry, derived thermogravimetry and gas chromatography coupled to mass spectrometry. Temperature and heating rate showed significant effects on responses. A linear model was suitable for gas yield, while quadratic models were suitable for the other responses. A trade-off analysis between bio-oil yield and phenol concentration detected optimal values of 42.8% and 46.9 mg∙g-1 at 530 ºC and 10.0 ºC∙min-1. Phenolic compounds accounted for 77.8% of the total bio-oil area based on the chromatography results. The charcoal produced by inflorescence pyrolysis at 650 ºC and 10 ºC∙min-1 was chemically activated with K2CO3 and applied to remove methylene blue in aqueous solutions. The coal produced was characterized using point of zero charge, FTIR, TGA/DTG, XRD, BET, SEM and CHNS techniques. Experiments were carried out to evaluate the adsorption kinetics using adsorbate concentrations of 25 mg·L-1, 50 mg·L-1 and 100 mgL-1. Coconut inflorescence charcoal had a point zero charge of 7.8, while activated charcoal had a point of zero charge of 5.8. Functional groups such as methyl, methylene, alkyl, carbonyl and aromatic groups were observed in the FTIR. Thermogravimetric analysis revealed three zones of degradation related to the weight loss of hemicellulose, cellulose, lignin and other organic components. In X-ray diffraction, no cellulose peaks were observed in the coals, indicating conversion during pyrolysis. Surface area analysis showed that raw charcoal had a surface area of 113.000 m²·g-1, while activated carbon had 515,345 m²·g-1. CHNS analyzes were similar to coals from coconut fiber. The pseudo-second order model was the most suitable for kinetic data adjustments. The SIPS model better represented the isotherms in the equilibrium study, and the thermodynamic parameters indicated that the adsorption is endothermic and spontaneous in 30 ºC and 40 ºC, although it is non-spontaneous in 50 ºC and 60 ºC. Therefore, the activated carbon produced was a good alternative adsorptive material for the treatment of water contaminated with methylene blue.
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7
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GEORGIA NAYANE SILVA BELO GOIS
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Co-digestion of BRS-Capiaçu elephant grass broth with swine effluent aiming at methane production
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Advisor : EDUARDO LUCENA CAVALCANTE DE AMORIM
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COMMITTEE MEMBERS :
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CARLOS EDUARDO DE FARIAS SILVA
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EDUARDO LUCENA CAVALCANTE DE AMORIM
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FERNANDA SANTANA PEITER
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LIVIA MARIA DE OLIVEIRA RIBEIRO
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NORMA CANDIDA DOS SANTOS AMORIM
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RODOLFO JUNQUEIRA BRANDAO
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Data: Nov 16, 2023
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Show Abstract
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Lignocellulosic biomass and agricultural residues rich in carbohydrates, lipids and proteins are promising sources for the production of renewable energy that are currently growing in the area of biofuel production. Analyzing the Brazilian agricultural and industrial market, there is a growing production of elephant grass and the consumption of pork. The juice of elephant grass and the effluent of swine farming, for presenting high levels of carbohydrate and nitrogen, can represent a favorable combination for the process of anaerobic codigestion aiming at the production of biogas. The objective of this study is to carry out the co-digestion of elephant grass (BRS-Capiaçu) (CC) and swine effluent (ES) to produce methane. With this, in a first step (E1) the experimental design of the Simplex Lattice type was applied in benchtop reactors in batch mode. Different proportions of the mixture (CC0/ES100, CC20/ES80, CC40/ES60, CC60/ES40, CC80/ES20, CC100/ES0) were evaluated by adjusting the linear and quadratic models. In E1, the results showed carbohydrate removal efficiency between 42.00 and 72.48%, COD between 18.78 and 53.82% and SVT between 34.81 and 54.78%. Co-digestion was favorable for the production of CH4, maximum values of 3921.90 mL-CH4/g-CODapl and 98.11 mL-CH4/(g-DQOapl.d) were obtained, both observed in the CC20/ES80 condition. The reactors CC40/ES60, CC60/ES40 showed similar results among themselves 3432.70 mL-CH4/g-CODapl and 3446.69 mL-CH4/g-CODapl, respectively. The quadratic model had the best fit (R2 equal to 0.92 and 0.94 for yield and methane production rate, respectively). The second stage (E2) will also be carried out in batch reactors, aiming at the production of methane, where the effect of the initial substrate concentration (COD), alkalizing concentration (NaHCO3) and the two best CC/ES compositions verified in E1.
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8
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NADJANE LEITE DOS SANTOS TELLES
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Hydrogen production from craft brewery wastewater by natural fermentation
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Advisor : EDUARDO LUCENA CAVALCANTE DE AMORIM
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COMMITTEE MEMBERS :
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AMANDA SANTANA PEITER
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ANTONIO PEDRO DE OLIVEIRA NETTO
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EDUARDO LUCENA CAVALCANTE DE AMORIM
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RENATA MARIA ROSAS GARCIA ALMEIDA
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RODOLFO JUNQUEIRA BRANDAO
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Data: Dec 12, 2023
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Show Abstract
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Technological development and changes in people's habits have increased the global need for energy and have been a concern of modern society. The search for sustainable energy development is an important issue in order to avoid an energy crisis and minimize the environmental impacts that occur due to the use of fossil fuels for many years. Given this scenario, hydrogen appears as an alternative source of energy, since its combustion generates only oxygen and water, thus being considered a clean and renewable fuel. The biological production of hydrogen, through anaerobic digestion, appears as an alternative for the processing of craft brewery waste, making it possible to combine energy generation (biogas) with the environmental framework of this waste without interfering with its quality. In this sense, the objective of this study was to evaluate the production of hydrogen from beer residue as a carbon source, seeking to establish optimal experimental conditions, using an experimental design 23, to evaluate the effect of the variables (Chemical Oxygen Demand - COD, type of inoculum and agitation) in two levels, resulting in 8 different experiments, carried out in duplicate, totaling 16 assays. The COD concentrations used were approximately 5 and 10 g. L-1, inoculum from natural fermentation and an anaerobic sludge, some reactors were submitted to agitation at 120 rpm and others kept without agitation. The effects of the dependent variables on the production of H2 were examined by analysis of variance (ANOVA) and the accumulated production was adjusted by means of the modified Gompertz function using the average of the values obtained by the replicas of the reactors in each treatment of the experimental design. The coefficients of determination (R2) of all adjustments were from 0.9916 to 0.9975, indicating that the applied model satisfactorily describes the progress of the cumulative hydrogen production. The maximum potential for hydrogen production and the production rate were obtained in reactor 5 (COD of 5 g. L-1, inoculum of natural fermentation and agitation of 120 rpm) in the values of 163.30 mL, and 0.52 mL /h, respectively.
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