Dissertações em Engenharia Química (Mestrado) - PPGEQ/ITEC

URI Permanente para esta coleçãohttps://repositorio.ufpa.br/handle/2011/2309

O Mestrado Acadêmico iniciou-se em 1992 e pertence ao Programa de Pós-Graduação em Engenharia Química (PPGEQ) do Instituto de Tecnologia (ITEC) da Universidade Federal do Pará (UFPA).

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Agora exibindo 1 - 7 de 7

Acesso aberto (Open Access)
Adsorção de ácido 2,4-diclorofenoxiacético em carvão ativado granular de resíduos de buriti (mauritia flexuosa l.): estudo em batelada e leito fixo. Orientador: Lênio José Guerreiro de Faria. 2024. 135 f.
(Universidade Federal do Pará, 2024-12-27) ARAÚJO, Raíssa Cristine Santos de; FARIA, Lênio José Guerreiro de; http://lattes.cnpq.br/7428609361678173
Pesticides, when applied responsibly, are essential for agricultural productivity, however, depending on their dosage or frequency of exposure, they can cause numerous problems for human health, in addition to the contamination of soil and surface or underground water. Following this problem, this manuscript aimed to evaluate the adsorption of the herbicide 2,4- dichlorophenoxyacetic acid (2,4-D) using physically activated granular carbon (CAT) and chemically activated granular carbon with ZnCl2 (CAQ) produced from the endocarp and endosperm of buriti (Mauritia flexuosa L.), typical fruit from the Amazon region. The adsorbents were characterized in terms their textural and physicochemical properties through the percentage of ash, moisture, specific surface area (SBET), pore volume (Vtotal), by SEM/EDS, XRD, FTIR spectroscopy, TGA/DTA, the surface functional groups, point of zero charge (pHPCZ) and the surface pH of the carbon. Batch adsorption tests were carried out to elucidate the influence of activated carbon dosage and the effect of solution pH. The adsorption mechanisms and the nature of the process were investigated by studying the kinetics, equilibrium and thermodynamics for the coal with the highest performance. The best results for adsorbate removal percentage were CAT (96.93%) and CAQ (92.46%) and the adsorption capacity CAT (29.00 mg.g-1 ) and CAQ (137.70 mg.g -1 ) within 24 hours, pH 2.0 and dosage of 0.25 g of CAT and 0.05 g of CAQ. The CAQ adsorbent showed superior results in removal and adsorption capacity, with its kinetics fitting the pseudo-second order model, with external diffusion being the determining stage of the adsorption process. The isotherms were satisfactorily fitted to the Sips model. The thermodynamic data revealed the endothermic, physical and spontaneous nature of the adsorption process. The adsorption on fixed bed confirmed that the adsorvent mass, concentration of solution and the inlet flow were influent in the adsorption process, highlighting the efficiency of simultaneous optimization tecnic, within the experimental region explored in this work. Both interactions showed that the charcoals produced present high yield, with the development of pores and surface groups, and excellent performance in removing the 2,4-D herbicide, promising substitutes for commercial carbons.
Acesso aberto (Open Access)
Caracterização, análise fluidodinâmica e secagem de sementes de painço em leito de jorro
(Universidade Federal do Pará, 2014-05-16) NASCIMENTO, Lidiane Diniz do; COSTA, Cristiane Maria Leal; http://lattes.cnpq.br/0581730621014796; FARIA, Lênio José Guerreiro de; http://lattes.cnpq.br/7428609361678173
S. italica seeds were analyzed in chemical, physical and qualitative aspects and then the fluidynamics was evaluated at ambient temperature, for different loads of material in two spouted bed configurations: conical (500, 800, 1100 and 1400 g ) and conventional ( 1300, 1700 and 2100 g). From the experimental data it was found that the particles were suitable for the system used, so the operating parameters of the spouted bed were collected , which were compared with their theoretical values calculated by empirical correlations available in literature. According to experimental conditions, it was necessary to choose only one of the configurations of spouted bed, so it was decided to operate the conventional spouted bed. For the seed drying kinetics only the optimal load (1700g) was utilized and the temperatures used were 44 , 65 and 86 °C, verifying the absence of constant drying rate, indicating that drying was controlled by diffusion mechanisms. The effective moisture diffusivity was estimated, resulting in the range from 0.7729x10-11 to 2.3189x10-11 and the relationship between the temperature and the effective moisture diffusivity was described by Arrhenius equation, providing an activation energy of 24,86 kJ/mol. The mathematical models that best described the drying curve were Diffusion Approximation, Page and Midilli et al. Furthermore, a rotational central composite design was applied with the objective of evaluating the influence of the independent variables time (X1) and temperature (X2) on the responses moisture ratio (XR), germination (G) and speed germination index (SGI) . The chosen answers are necessaries in the seeds quality control, as in the case of the moisture content during the storage. The G and SGI responses are indicative of the physiological state of the seeds, which are also important, in accordance with the purpose of the product. Through statistical analysis, for a confidence interval of 95%, it was found that XR and SGI were influenced only by X1, X2 and X22 , while G was statistically affected by X2 and X22 . The effects for all responses were negative , indicating that SGI and XR decrease with increasing of temperature and drying time. The answer G decreases with increasing of temperature. Quadratic models were proposed by the statistical analyzes, reaching good correlation coefficients (R2); 0.9632 (XR), 0.8998 (G) and 0.9724 (SGI). Then, the optimal value of the foxtail millet drying process was determined, using the concept of Desirability Function, which was corresponding to a drying time of 121 min at a temperature of 64 ° C, getting seeds with 82.99% of germination; speed germination index of 29.33 (dimensionless) and final moisture content of 11%.
Acesso aberto (Open Access)
Destilação fracionada do óleo essencial de P. aduncum L. rico em dilapiol
(Universidade Federal do Pará, 2011-09-30) MARTINS, Gisele Luciana Domont; FARIA, Lênio José Guerreiro de; http://lattes.cnpq.br/7428609361678173
The species Piper aduncum L. is a shrubby plant, popularly known in the Amazon as monkey-pepper (spiked pepper). An essential oil, rich in dillapiol, can be extracted from this plant, which is of great economic interest for its insecticidal and pesticide action in agriculture. This biopesticide is an alternative to replace synthetic insecticides as it is from natural origin and does not cause damage to the environment and human health. In this paper the physical properties of the essential oil of spiked pepper were analyzed. The oil was obtained by steam distillation which showed mean values of refractive index of 1.516 and specific mass 1.08 g/cm³. The fractional distillation of the essential oil was studied, in order to concentrate the compound of interest, thus, adding greater economic value and enabling its use in the production of new products. In this process a high purity compound is obtained. The assessment was performed using a mathematical model to evaluate the concentration of dillapiol at the bottom of the distillation flask by regression analysis as a function of operating time which set the experimental data very well. The analysis of the results suggests that the process of fractional distillation can be used to separate the useful constituents from the essential oils. This is only possible because the essential oils are constituted of several volatile organic compounds with different boiling points and steam pressures, making the separation viable. The highest content of dillapiol obtained experimentally by the method of fractional distillation was 95 %, operating under vacuum conditions (40 mmHg) and mean temperature of the column of 122 ºC, and the average yield obtained was 41 % (v/v).
Acesso aberto (Open Access)
Fotocatalisadores de dióxido de titânio dopados com metais de transição: síntese, caracterização e aplicação na fotodegradação de fármacos
(Universidade Federal do Pará, 2024-12-27) AZEVEDO, Carla Arnaud de; FARIA, Lênio José Guerreiro de; http://lattes.cnpq.br/7428609361678173
Heterogeneous photocatalysis has shown promise in ecological remediation and in the adequate treatment of pharmaceuticals as emerging contaminants. This study evaluated the photocatalytic activity of materials synthesized from the modification of the TiO₂ surface with transition metals (copper and cobalt) at concentrations of 0.5% and 1.5%, analyzing the physical, chemical and textural properties of the materials by N2 physisorption (BET) analysis, X-ray diffractometry (XRD), scanning electron microscopy–energy-dispersive X-ray spectrometry (SEM-EDS) and Fourier transform infrared (FT-IR). The experimental tests were carried out in an annular photoreactor with UV mercury lamp, following the Box-Behnken design, to evaluate the influence of catalyst mass (50 – 150 mg.L-1 ), drug concentration (2 – 8 mg.L-1 ) and irradiation time (60 – 120 min) on the photodegradation of acetaminophen (ACT) and diclofenac sodium (DCF). The BET results indicated that the materials have a mesoporous structure with an average pore diameter of 14.52 nm. XRD characterization confirmed the mixed structure of anatase and rutile and the absence of metal oxide peaks. The SEM-EDS analysis revealed irregular surfaces formed by misshapen grains and small particles attributed to metal oxides. The FT-IR showed O-H and Ti-O stretching bands, characteristic of photocatalytic materials. The FTCu1.5 photocatalyst was chosen for use in the photodegradation tests of the drugs due to its surface area, porosity and good anatase and copper content. The photocatalysis tests, in comparison with the photolysis tests, showed superior results, evidencing the functionality of the photocatalyst used. The degradation percentages reached 100% for both drugs and the concentration of the pollutant solution had a negative effect on the response variables, indicating that degradation increases with the reduction of the initial concentration of this solution. The proposed polynomial models presented a coefficient of determination (R²) > 0.9 and good predictive capacity. The Response Surface Methodology (RSM) and Desirability Function analyses indicated that it is possible to obtain a substantial reduction in the amount of photocatalyst used, when combined with an adequate adjustment in the irradiation time. The optimal conditions within the experimental domain for ACT are mcat = 100 mg.L-1 , CFA = 2 mg.L-1 and tIRR = 75 minutes, resulting in EffACT(%) = 99.05% and for DCF, the optimal conditions were mcat = 72 mg.L-1 , CFA = 2 mg.L-1 and tIRR = 65 minutes, resulting in EffDCF(%) = 90.39%. The developed photocatalyst significantly degraded the drugs and demonstrated promise for photocatalysis applications.
Acesso aberto (Open Access)
Influência das características do fluido na corrosão e erosão em amostras de aço 5l x65
(Universidade Federal do Pará, 2024-09-30) NASCIMENTO, Nina Benchimol Xavier do; FARIA, Lênio José Guerreiro de; http://lattes.cnpq.br/7428609361678173
The objective of this research was to evaluate the corrosive and erosive behavior of API 5L X65 carbon steel samples with an external FBE coating used for transporting an aqueous suspension containing around 40% solids with a high content of aluminum hydrated silicates, mainly kaolinite and water, to identify the best operational method for intermittent pumping regimes, focusing on their influence on steel integrity. The samples were divided as follows: three samples of carbon steel pipes with an outer diameter (OD) of 14 inches, thickness (Th) of 8.74 mm (original), and 1 meter in length; a sample of process water and a sample of aqueous suspension with an average of 40% solids with a high content of aluminum hydrated silicates and acidic pH, each with approximately 60 liters (divided into two plastic containers of 30 liters). The results show that the KM-0 sample presented a yield limit below the specified minimum, and the KM-23 sample also showed a high standard deviation, suggesting a lack of homogeneity. The new pipe samples presented values within specifications. The significant difference in hardness between samples lies in the very low carbon percentage presented in the TR sample. This minimizes issues with potential weak points and increases material weldability; however, in some cases, pipes treated by controlled rolling achieve high mechanical strength and toughness with relatively low hardness, which can provide greater erosion resistance than tempered pipes. Samples KM-23 and KM-0, although having similar hardness and chemical composition, showed differences in absorbed energy and area reduction. This may be attributed to the higher sulfur content in sample KM-23, evidenced by detected sulfur-rich inclusions. Overall toughness was high for all samples, with no indication of brittleness under the tested conditions. The results of uniform and localized corrosion, disregarding the influence of oxygen, indicated that the acidic pH slurry is less corrosive than water. During water operation, the corrosion rate stabilizes over time; however, when production is intermittent, the film formed by water disappears, returning this rate to its initial condition, being even more detrimental to the pipe's integrity.
Acesso aberto (Open Access)
Otimização do processo de extração do óleo essencial de priprioca (Cyperus articulatus L.) por arraste com vapor
(Universidade Federal do Pará, 2009-05-29) CORUMBÁ, Lorena Gomes; FARIA, Lênio José Guerreiro de; http://lattes.cnpq.br/7428609361678173
It is analyzed the process of extraction of the essential oil of priprioca (Cyperus articulatus L.) rhizomes experimentally with water steam, in a prototype in bench scale. Through design of experiments and response surfaces methodology, they are considered the optimal conditions to maximize the response variables yield and mustakone concentration, majority component of the essential oil of priprioca, in function of operational entrance variables of the process. The independent variables and respective levels are: load or mass of priprioca rhizomes, in grams (64, 200, 400, 600, 736); granulometry of the rhizomes, in millimeters (0,61; 1,015; 1,6; 2,19; 2,58) and extraction time, in minutes (44, 60, 90, 120, 140). Using a central composite design, with aid of the application StatisticaR 7.0, mathematical models are proposed for the responses in function of the isolated independent variables and of their combinations. It is verified that the yield in essential oil and the mustakone tenors can be fitted appropriately for second order polynomials models. They are obtained larger yield simultaneously in oil and mustakone tenors, when the load of rhizomes varies from 105 to 400 grams for extraction times between 105 and 140 minutes.
Acesso aberto (Open Access)
Processo de secagem de Morinda citrifolia L. em secador de radiação com lâmpadas refletoras, utilizando planejamento composto central rotacional
(Universidade Federal do Pará, 2015-10-16) BARROS, Hellen Carvalho; BRASIL, Davi do Socorro Barros; http://lattes.cnpq.br/0931007460545219; FARIA, Lênio José Guerreiro de; http://lattes.cnpq.br/7428609361678173
Morinda citrifolia Linn, popularly known as Noni, is a plant in the Rubiaceae, family that has been used for many centuries in popular medicine. The ancestors of the Polynesians discovered the plant and there have been numerous reports of its therapeutic and nutritional properties. For that reason, it was decided to carry out a study with the fruits of the species Morinda citrifolia L., in order to encourage use of the fruit for consumption in people’s diet, as well as to confirm its functional potential after drying. In this research, the conditions for drying Noni fruits were studied, and the phenolic compounds and antioxidant activity of the extracts obtained were assessed and quantified. In the drying process a dryer with reflecting lamps was used at the laboratory scale. In analyzing the process a statistical model was used as a basis, to quantify the effects of the entry variables in the Responses, by means of regression analyses through rotational central compound planning (PCCR) with two entry variables and five levels, employing temperature and size of the pulp as entry variables and final humidity level, antioxidant capacity and free radical sequestration activity as responses. It was observed that increasing the drying temperature led to a decrease in the final humidity level of Morinda citrifolia L fruits.The values of the responses observed varied from 0,01 a 3,50 bs, for drying; 1,32% a 38,8%, and 12,54 to 26,56(mg Eag/g) for phenolic levels.Within the experimental domain, only the variable of the isolated entry X1 (temperature) in the linear and quadratic forms were statistically influential on the Xbsresponse variable.

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