Mestrado em Energia
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- ItemSíntese e otimização de compositos de ferro e bismuto para a fotodegradação de poluentes orgânicos(Universidade Federal do Espírito Santo, 2025-02-25) Costa, Kaio Reis; Proveti, José Rafael Cápua ; https://orcid.org/0000-0002-8809-9791; http://lattes.cnpq.br/2820404320026694; Muniz, Eduardo Perini ; https://orcid.org/0000-0002-0500-4786; http://lattes.cnpq.br/8285018770645807; https://orcid.org/0009-0000-0866-1442; http://lattes.cnpq.br/5804147672203766; Andrade, George Ricardo Santana ; https://orcid.org/0000-0002-1772-9477; http://lattes.cnpq.br/1419428893704446; Ferreira, Nilson dos Santos ; https://orcid.org/0000-0002-8421-2558; http://lattes.cnpq.br/1199350032937783The increasing contamination of water bodies by detergents, with linear sodium alkylbenzene sulfonate (LAS) as the main component, constitutes a major environmental challenge. This research analyzed the synthesis and optimization of iron and bismuth oxides for application in heterogeneous photocatalysis, aiming at the degradation of the detergent, having as a parameter to determine whether the destruction of the detergent molecules occurred the decrease in their absorbance and fluorescence. The composites were synthesized via the sol-gel route using iron nitrate, bismuth nitrate and pectin present in orange peel. The synthesis variables were the calcination temperature (500; 550; 600; 700; 800 °C) and the Bi/Fe molar ratio (0; 0.25; 0.5; 0.75; 1.0; 1.25). X-ray diffraction revealed the formation of a multiphase system with BiFeO₃, Bi₂Fe₄O₉, α-Fe₂O₃ and γ-Fe₂O₃. Presenting up to 88% BiFeO₃ in the bismuth-rich sample and 98% α-Fe₂O₃ in the iron-rich sample. Scanning electron microscopy (SEM) demonstrated the formation of a “flower-like” morphology for samples calcined between 500 and 600 °C. The degradation efficiency via photocatalysis was quantified in a solution of 100 mg/l of liquid detergent, using LEDs from a discarded television and 15 mg of iron-bismuth composite as radiation source. Among all the samples, the one produced with 0.5 mol of iron for 1 mol of bismuth and calcined at 500°C was the one that decreased absorbance the most, by more than 40%, with a reduction of more than 10% in fluorescence
- ItemRota de conversão de resíduos poliolefínicos em combustíveis : simulação e previsão do índice de mistura em reatores de leito de jorro(Universidade Federal do Espírito Santo, 2025-02-24) Louvem, Renata Falqueto; Ribeiro, Daniel da Cunha ; https://orcid.org/0000-0003-3690-1938; http://lattes.cnpq.br/8563308324482367; Bacelos, Marcelo Silveira ; https://orcid.org/0000-0002-0838-6839; http://lattes.cnpq.br/3741207242086712; https://orcid.org/0009-0009-9292-7586; https://orcid.org/0009-0009-9292-7586; Santos, Kassia Graciele dos ; https://orcid.org/0000-0001-7452-6900; http://lattes.cnpq.br/9680475824447820; Siqueira, Renato do Nascimento ; https://orcid.org/0000-0002-8397-8180; http://lattes.cnpq.br/9791817633014124Pyrolysis in spouted bed reactors with mixtures of polyethylene/aluminum composite particles (LDPE/Al) and sand promotes the waste valorization route for fuel production. However, unstable regimes caused by mixtures of particles with different sizes and specific masses can compromise thermal conversion in the reactor. To contribute to the carton waste management route, this work aims to validate gas-solid flow model in beds composed of sand and composite mixtures through experimental data from the literature. The 2D Euler-Euler granular model is tested with particle mixtures at 30% and 50% composite concentrations and diameter ratios of 1.39 and 2.54. The simulation can predict stable conditions and segregation levels of Mantegazini et al. (2021) and is consistent with experimental data on glass spheres reported by San José et al. (1994). The model can determine the mixing index (Im) of the bed in spouting and collapse regimes with an error of less than 10%. The results indicated that decreasing the diameter ratio and composite concentration in the bed promotes more homogeneous mixtures with Im values close to 1. This research contributes to the fuel production route, in addition to enhancing the valorization and management of solid carton-based waste
- ItemSimulação computacional do efeito da turbulência na hidrodinâmica de misturadores estáticos Kenics® aplicados à fotocatálise(Universidade Federal do Espírito Santo, 2024-11-13) Schneider, Bruno de Oliveira; Xavier, Thiago Padovani; https://orcid.org/0000-0001-7148-9921; http://lattes.cnpq.br/8669754182140698; Lira, Taisa Shimosakai de ; https://orcid.org/0000-0002-2690-242X; http://lattes.cnpq.br/8699243861996813; https://orcid.org/0009-0005-2273-2266; http://lattes.cnpq.br/7397231442316912; Bacelos, Marcelo Silveira; https://orcid.org/0000-0002-0838-6839; http://lattes.cnpq.br/3741207242086712; Santos, Kassia Graciele dos ; https://orcid.org/ 0000-0001-7452-6900; http://lattes.cnpq.br/9680475824447820The treatment of industrial effluents can be considered an essential factor for sustainable development. Among the advanced oxidative processes (AOPs) applied, heterogeneous photocatalysis stands out due to the possibility of using solar energy and because it occurs at ambient pressure and temperature. Its large-scale application depends on improving the performance of photocatalytic reactors, with the compound parabolic collector reactor being one of the most promising. In this context, the use of static mixers has emerged as an alternative to improve mixing parameters and increase the rate of pollutant degradation. Although there are studies evaluating the main commercial mixers or geometries developed by the author, there is a lack of analysis of the hydrodynamic effect of using mixers in heterogeneous photocatalysis processes. The aim of this work was to numerically evaluate the effect of static mixers on the hydrodynamics of the photocatalytic process in a compound parabolic trough reactor. To do this, the flow inside the reactor was numerically simulated using Ansys Fluent® software for Reynolds numbers of 4,500 and 30,000. The contour plots and current lines of the normalized axial velocity along the tube and in different sections of the mixer were analyzed. The pressure drop resulting from the use of mixers was also evaluated. The results showed that the static mixer promoted the formation of vortices in different regions of the tube, an increase in the velocity gradient and turbulence in the flow. In addition, the geometry of the mixer favored the direction of the fluid towards the edge of the tube, a region that is most affected by radiation. These phenomena contribute to a better dispersion of the catalyst and the effluent in this region, which favors the heterogeneous photocatalytic reaction. Increasing the Reynolds number from 4500 to 30000 contributed to the formation of well-defined vortices, a reduction of the vortices, a reduction in backflow and an increase in higher velocity zones. Therefore, there was a positive effect on the hydrodynamic performance of the reactor
- ItemCompósito de Luffa cylindrica e óxido de cobre para a dessalinização da água do mar(Universidade Federal do Espírito Santo, 2024-09-25) Flores Vasquez, Katherine Jisselle; Bacelos, Marcelo Silveira ; https://orcid.org/0000-0002-0838-6839; http://lattes.cnpq.br/3741207242086712; Andrade, George Ricardo Santana ; https://orcid.org/0000-0002-1772-9477; http://lattes.cnpq.br/1419428893704446; https://orcid.org/0009-0002-3589-5118; http://lattes.cnpq.br/8713161231510324; Meireles, Carla da Silva ; https://orcid.org/0000-0003-4450-5708; http://lattes.cnpq.br/9685470701740945; Barbosa, Cintya D' Angeles do Espirito Santo ; https://orcid.org/0000-0003-2620-8240; http://lattes.cnpq.br/1197509333716425The increasing demand for water requires more efficient, economical and sustainable desalination processes. Solar desalination is a promising solution, but its low energy efficiency limits large-scale production. Research indicates that the addition of photothermal absorbing materials (PTMs) can improve this technology. This study aims to develop PTMs by combining loofah (Luffa cylindrica) and Cu2O, to increase the efficiency of conventional solar desalination. Thus, the composites were prepared by adsorbing copper ions on loofah (in natura or after alkaline treatment) followed by a heat treatment at 220ºC. Characterization was performed using OM, XRD, UV-Vis, SEM, ZPC, and thermographic imaging techniques. The XRD results revealed the presence of peaks related to the graphitic phases and Cu2O with cubic structure. OM and SEM/EDS data showed that the loofah structure remained unchanged after heat treatment and that Cu2O particles were uniformly distributed on the surface of the loofah fibers. The composites presented high light absorption in the UV-vis region and, consequently, higher surface temperature after exposure to sunlight. Solar evaporation tests using the composite without alkaline treatment, chosen because it presented the highest surface temperature when exposed to direct solar radiation, resulted in conversion efficiencies between 76.9% and 98.6% for distilled water and 88.1% for seawater. These results indicate the direct influence of the amount and exposed surface of the composite on efficiency. In addition, a distiller with a glass body was designed and built, which, when incorporating the absorbing material, increased the average desalination efficiency by 94%. Physicochemical analyses of the water obtained, such as pH, chloride quantification and electrical conductivity, confirmed the desalination of seawater. The composite showed better conversion efficiency and a significant increase in the productivity of solar distillation than other similar materials in the literature. Therefore, this work innovates by developing a material with high potential for solar desalination, contributing to mitigate the effects of water scarcity
- ItemAvaliação da eficácia de um reator retangular, contínuo, com eletrodos em formato de chicanas no tratamento de efluentes oleosos por eletrocoagulação(Universidade Federal do Espírito Santo, 2024-10-29) Leite, Daniela Luz; Andrade, George Ricardo Santana; https://orcid.org/0000-0002-1772-9477; Porto, Paulo Sérgio da Silva; https://orcid.org/0000-0002-6486-7813; Faria, Rochkhudson Batista de; Pinto, Luiz Antônio de AlmeidaOily waters from various industrial sectors are effluents containing millions of liters of oil-in-water (O/W) emulsions, requiring prior treatment before disposal. Research on electrocoagulation (EC) to recover oily effluents has been highlighted. Electrolysis, a non-spontaneous reaction that releases metal into the medium, decomposes the synthetic emulsion, resulting in the formation of flakes in the medium. The flakes integrated with the gas bubbles culminate in the separation of the oil and the obtaining of the treated effluent. This research explored the rectangular geometry, applied to an EC reactor, in the search for an efficient and rapid recovery of emulsified oil in water. The influence of the volumetric flow rate and the polarity inversion time in this process were evaluated. The dependent variables include turbidity, pH, aluminum (Al) concentration, residual oil content and zeta potential. The rectangular reactor was equipped with Al electrodes arranged in the form of baffles, connected by a polarity inverter, operating in continuous mode. The best results were obtained using 2.58 mL/s in the inlet flow rate and 20 s of polarity inversion time, achieving 95.62% oil removal and 97.87% turbidity removal. The highest energy efficiency was obtained using 4 mL/s and 20 s of the parameters recently mentioned, obtaining 89.86% oil removal and 95.70% turbidity removal. The zeta potential analysis showed that the EC alters the stability of the emulsion. The pH remained within the legal requirements throughout all experiments. The wear of the plates was minimal, stipulating that their reuse can be implemented. Complementary tests indicated that the use of perforated electrodes increases the efficiency of contaminant removal, as well as indicating that the reuse of electrodes for twice the time reduced the aluminum concentration at the reactor outlet. Despite this, in all experiments the amount of aluminum obtained was higher than the current standard, indicating the need to add another step in this process, in order to retain Al3+ ions.