Engenharia Química
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Programa de Pós-Graduação em Engenharia Química
Centro: CCAE
Telefone: (28) 3552 8719
URL do programa: http://www.engenhariaquimica.alegre.ufes.br/pos-graduacao/PPEQ
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Navegando Engenharia Química por Autor "Brito, Gilberto Augusto de Oliveira"
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- ItemEletrocatalisadores de platina promovidos com NiO aplicados na reação de oxidação de biocombustíveis.(Universidade Federal do Espírito Santo, 2018-02-26) Moraes, Maurício Carlos; Pinheiro, Christiano Jorge Gomes; Profeti, Demetrius; Profeti, Luciene Paula Roberto; Guimarães, Damaris; Brito, Gilberto Augusto de OliveiraRenewable energy is key to supplying new technologies, and a promising alternative to generate clean energy would be the fuel cell (CF), which produces electricity with reduction of pollutants, and with the use of biomass fuels, it becomes a sustainable source of energy. However, it is necessary to minimize the cost of production and to facilitate the supply of CFs to enable the large-scale application. In this context, catalysts composed of Pt and NiO were prepared, which were characterized by X-ray Diffraction, Dispersive Energy Spectroscopy and Scanning Electron Microscopy. The catalysts had a cracked-mud look, homogeneous distribution on the surface and concentrations close to the nominal ones. A direct relationship between crystallite size and Pt concentration was also observed. In addition, there was no alloying between Ni and Pt, since no changes were detected in platinum network parameters (cfc). The characterization of the electrocatalytic behavior of glycerol oxidation in PtxNi(1-x)Oy/Ti electrodes was investigated in alkaline medium. The catalysts were prepared by thermal decomposition of polymer precursors in different metal compositions with high electrochemical surface area. The results of cyclic voltammetry and chronoamperometry showed that glycerol oxidation current densities for mixed electrodes were higher than those obtained for electrodes containing only Pt at low potential values. In addition, the change in the onset potential of glycerol oxidation towards less positive values was also recorded, showing a facilitated oxidation with these materials compared to Pt. The electrodes that stand out are Pt0.8Ni0.2Oy/Ti and Pt0.9Ni0.1Oy/Ti because they have the highest electroactivity and the highest efficiency, respectively.
- ItemEstudo da adição de lítio a nanocatalisadores de óxido de cálcio para a produção de biodiesel(Universidade Federal do Espírito Santo, 2018-02-27) Soares, Thaís Machado; Pinheiro, Christiano Jorge Gomes; Barañano, Audrei Giménez; Guimarães, Damaris; Brito, Gilberto Augusto de OliveiraIn view of the environmental impacts caused by primary energy sources, federal agencies around the world are increasingly seeking to institute research aimed at new sources of energy from renewable natural resources. In this regard, we highlight biodiesel, created to replace diesel oil derived from petroleum. Industrially, the production of this biofuel is catalyzed by homogeneous catalysts, which end up giving certain limitations to the process. Thus, heterogeneous catalysis is an alternative that has been evaluated, being that calcium oxide (CaO) is one of the solid catalysts that has been highlighting, due to its high activity and low cost. However, CaO has presented leaching problems. In this context, the objective of this study was to present a diagnosis related to the addition of lithium in calcium oxide nanocatalysts, synthesized by the wet impregnation method and thermal decomposition, in order to evaluate which technical is more efficient to obtain a material with a greater stability and selectivity to serve as a heterogeneous catalyst in transesterification reactions of soybean oil via the methyl route. Using thermogravimetric (TGA), X - ray diffraction (XRD), spectroscopy (FTIR) and microscopy (SEM) and (TEM) techniques, for verification to the format and the elements present as well as the mean crystallite and the network parameters of the nanocatalysts. By means of the spectroscopy technique (1H NMR), it was possible to verify that the addition of lithium in the CaO nanocatalyst increased catalytic activity and selectivity in biodiesel. In addition, the techniques used for the synthesis of the nanoparticles provided greater stability to the material. For, the conversion of products into biodiesel was higher than 87% in the third reaction cycle.
- ItemEstudo de fatores que influenciam na macroporosidade de placas de baterias chumbo-ácido(Universidade Federal do Espírito Santo, 2019-02-20) Carvalho, Cynthia Mayara de; Brito, Gilberto Augusto de Oliveira; Pinheiro, Christiano Jorge Gomes; Freitas, Marcos Benedito José Geraldo de; Profeti, Luciene Paula Roberto; Profeti, DemétriusThe current global scenario of climate change requires the search for alternative energy sources and it is within this context that lead-acid batteries are, which have many advantages such as ease of manufacture, collection and recycling, low cost and good performance compared to other types of batteries. Due to the mentioned advantages, the lead-acid batteries will remain, for a long time, in the market. A leadacid battery owes its good performance also to the average pore size and the total porosity of its pasted plates. It is essential, for the purpose of control, that there be systematized studies of the influences that act on macropores and how they act, since these macropores are responsible for the mass transfer in the porous system of the plates of a lead-acid battery, besides making part of the charge and discharge reactions in these batteries. The objective of the present study is the understanding of how two factors affect macroporosity: Water quantity and soaking time. For this purpose, mini-plates of lead-acid batteries with variations in the water content added to the paste (made with PbO and water) from 8% up to 15% in mass fraction and miniplates that passed by soaking with time variations of 1h, 2h, 4h and 8h were prepared. The miniplates were characterized by macroporosity tests through the absorption of water to analyze the total porosity; X-Ray Diffraction (XRD) for analysis of crystalline phases; Scanning Electron Microscopy (SEM) for analysis of the morphologies and Brunauer, Emmett, Teller (BET) method for surface area analysis. The results showed an increasing and quadratic relationship between macroporosity and water quantity in the precursor and active positive materials and a decreasing and quadratic relationship between soaking time and macroporosity for the precursor material. For the BET surface area an increasing and quadratic relationship was found with the amount of water and macroporosity for the precursor material. For the positive active material the relation was decreasing and quadratic.
- ItemSíntese e caracterização de nanopartículas de Cu-ZnO e sua utilização no revestimento de superfícies de titânio por deposição eletroforética(Universidade Federal do Espírito Santo, 2017-07-05) Gênier, Francielli Silva; Brito, Gilberto Augusto de Oliveira; Pinheiro, Christiano Jorge Gomes; Barañano, Audrei Gimenez; Guimarães, DamarisThe majority of metallic implant failures is due to body rejection to the material’s surface and to postoperative infections. Therefore, preventing bacterial growth on these materials and simultaneously contributing to their body adaptation are the main goals of recent researches on nanomedicine. As a way to reach these objectives, coating metallic prosthesis with nanoparticles represents a viable alternative to traditional treatment methods such as antibiotic administration, whose efficacy decreases as antibiotic-resistant strains of bacteria rise. The present work presentes the use of cooper doped zinc oxide nanoparticles (Cu-ZnO) to coat titanium surfaces, a commonly used material in medical devices, by electrophoretic deposition. These nanoparticles were chosen due their antibacterial characteristics, as presented on recent publications. Through microscopy (SEM and TEM), spectroscopy (EDS), and X-ray diffraction (XRD), the format and composition of the nanoparticles was confirmed as well as their crystallite size (228.24 nm) and lattice parameters. This material was suspended and deposited by electrophoresis on titanium plates for 1 minute under voltages between 100 and 180 V in order to obtain the best deposition condition, which was 160 V. The pH and conductivity of the suspension was also evaluated before and after the EPD. The EDS results confirmed the presence of the nanomaterial in the deposit. SEM images confirmed the increased surface roughness after electrophoretic deposition. Hence, this work’s goal was to explore a new potencial coatings process for artificial implants, in the way of contributing to the nanotechnology research field and its applications on medicine.