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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Acesso aberto (Open Access)
Reciclagem de resíduo a partir de cinzas de carvão mineral: produção de argamassas
(Universidade Federal do Pará, 2001-07-06) SIQUEIRA, Jacilene Siqueira de; SOUZA, José Antônio da Silva; http://lattes.cnpq.br/6157348947425968; SOUZA, Célio Augusto Gomes de; http://lattes.cnpq.br/0800747860976046
This work aims to evaluate the possibility of use of waste obtained from the combustion of coal in fluidized bed boilers, an alumina refinery in Pará state. In this context, we evaluated the incorporation of fly ash as pozzolan, to partially replace cement in mortar production. To that end, samples were prepared using Portland cement type CPII-E-32. The mixtures were in the ratio 4:1, that is 4 parts aggregate (silica) and 1 part of binder (cement and ash), with the inclusion of the ash of 10, 20, 30, 40 and 50 percentage with respect to the cement, beyond the mortar without addition. We defined two relation water / binder, 0,4 and 0,8. After 7 and 28 days curing time, were tested for compressive strength analysis of behavior. In addition, the mortar with the water / binder 0.8 were subjected to further analysis of X-ray diffraction, scanning electron microscopy, water absorption, porosity and bulk density, the results obtained were consistent when compared with literature data, showing that viable application of ash studied in the construction industry.
Acesso aberto (Open Access)
Síntese e caracterização de analcina obtida a partir de rejeito caulim com aplicação em adsorção
(Universidade Federal do Pará, 2006-12-19) CORREA, Edinelson Saldanha; NEVES, Roberto de Freitas; http://lattes.cnpq.br/9559386620588673
In this work from kaolin processing industries from Ipixuna-PA were used in order to synthesi analcime derived zeolite as predominant crystalline phase though the hydrothermal process. The sample was converted into metakaolinite by calcinations at 700°C during 4 hours. From sample this metakaolinite a reacting mixture consisting of diatomite and sodium hydroxide was prepared. In order to determine of ideal conditions for analcime synthesis, a number of process variables were measured such as sodium availability, silicon ratio, nature of the silica source, pH of the reacting mixture, and auto clave residence time. Some important properties of the adsorbent where measured as well, such as thermal stability in the presence of acids hydrogen desorption kinetics, the trends of the adsorption isotherms as such as selectivity for copper, cadmium, zinc and nickel ions. Analcime synthesis from kaolin processing wastes was feasible. A displacement in the (h, k, l) planes was observed at 400 °C and was maintained up to 600°C, caused by the withdrawal of oxygen in positions 1/8 in analcime, shrinking the unit cell and in active channels and sites of zeolite, affecting its adsorption capacity.
Acesso aberto (Open Access)
Modelagem e simulação do processo de separação por membrana difusa polimérica para a extração de metais
(Universidade Federal do Pará, 2007-02-16) CARDOSO, Simone de Aviz; QUARESMA, João Nazareno Nonato; http://lattes.cnpq.br/7826389991864785
Metal extraction process using polymeric membranes is analyzed by using the lines-Gear method in the solution of the related equations of specie conservations. The mathematical modeling of the physical problem is done by considering the diffusion process of metals in polymeric membranes in order to extract metals, such as Cd (II), Au (III) and Pd (II) from acid solutions. Therefore, the behavior of concentration profiles of metals to be extracted from the feeding phase is discussed in the light of the influence of relevant parameters in the extraction process, such as, composition and thickness of the membrane, diffusion coefficient and constant extraction. Comparisons with previously reported results in the literature for typical situations are also performed. The obtained results were very satisfactory when they were compared with other found results in the literature.
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)
Produção de biodiesel da gordura de murumuru (Astrocaryum murumuru) via catálise heterogênea
(Universidade Federal do Pará, 2010-09-24) TEIXEIRA, Louise Carolina Gonçalves; FRANÇA, Luiz Ferreira de; http://lattes.cnpq.br/6545345391702172; CORRÊA, Nádia Cristina Fernandes; http://lattes.cnpq.br/5763999772352165
This work investigated the feasibility of Murumuru oilseed (Astrocaryum murumuru) as raw material for biodiesel production through the use of heterogeneous catalysis in the basic transesterification. Murumuru is a fruit composed of pulp and kernel, producing about 50% of white fat, odorless, with the advantage of not be tasteless easily because it is rich in saturated fatty acids of short-chain such as for lauric and myristic. The biodiesel is conventionally production through the basic homogeneous catalysis. However this catalysis presents a few inconvenients, such as saponification of esters and the difficulty of removing the catalyst. On the otter hand, the heterogeneous catalytic route avoids the drawbacks of homogeneous catalysis, reducing the amount of aqueous effluent generated during the process and reuse of catalysts. The heterogeneous catalyst hydrotalcite, was synthesized and evidenced by analysis of X-ray fluorescence, X – ray diffraction, thermal analysis, textural analysis (BET method) and electronic scanning microscopy. A complete factorial planning was conducted using methanol as reacting product. Independent variables were temperature, molar ratio and catalyst concentration and the response variable was the conversion, measured through spectrophotometric method. These reactions were conducted in to a pressurized batch reactor. The best conversion found through factorial planning was 88,97% for molar ratio of methanol/oil worth 12, temperature of 200ºC and catalyst concentration equaling 6% in 1 hour of reaction. For this condition, kinetic studies were performed and tested the use of ethanol; through the kinetic study a good correlation can be achieved between the kinetic constants and conversion when using the model that considers reversible reaction, chemical reaction as controlling stage following the Eley Rideal mechanism.
Acesso aberto (Open Access)
Avaliação das condições de secagem no rendimento e na qualidade do óleo de linhaça (Linum usitatissimum L.)
(Universidade Federal do Pará, 2011-06-20) VALENTE, Maria da Conceição da Costa; COSTA, Cristiane Maria Leal; http://lattes.cnpq.br/0581730621014796; SOUZA, Célio Augusto Gomes de; http://lattes.cnpq.br/0800747860976046
From Asian origin flaxseed (Linum usitatissimum L.) and belongs to the linaceae family and it is obtained from flax. It is considered a functional food, because it contains substances that may prevent diseases such as degenerative and cardiovascular diseases. Flaxseeds are still a major lignans source, that are photochemical compounds similar estrogen, which it may performs cancer-preventative. In addition to being one of the richest sources of α-linolenic acid oil and soluble fibre. The drying is a unit operation, in general, usually means removal of relatively small amounts of water from material by evaporation or by sublimation, applying heat under control conditions. Aiming to analyze the behavior of flax seeds during the drying operation, this study aimed to perform the experimental design and statistically analyze the results used to quantify the influence of air temperature (T), drying time (t) fluidization air velocity (Uf) and solids loading (Cs) on the humidity ratio (Xr), oil yield (Rend.) and the parameters oleochemicals. The estimate of the optimal point of operation was determined according to the input variables by applying the concept of global desirability. Among the conditions set out in this work, the optimal value of the function you want and when T is shifted to high level (72 oC), Uf is shifted to high level (0,83 m/s), t you for the minimum (3h ) and Cs for the secondary level (500 g), thus obtaining: 0.126 to Xr, 36,92 % for Rend.; 4.51 mg KOH/g for IA, 22,52meq O2/g IP and 0,31% for DC. We obtained the sorption isotherms of flaxseed at temperatures 40, 60 and 80 °C. Six mathematical models were applied to analyze the experimental data. The enthalpy and differential entropy were determined by appying Clausius-Clapeyron and Gibbs-Helmholtz equation, respectively. Peleg model and GAB model showed the best fit to experimental data. The enthalpy-entropy compensation theory was applied to the isotherms, indicating that they are enthalpy - controlled. The flaxseed Drying were evaluated in a fixed and fluidized bed dryer, the experimental runs were done at temperatures 40, 60 and 80 °C. Five mathematical models were evaluated and the Midilli et al. model was found to be the best model for describing the flaxseeds drying behavior. It was observed that the effective diffusivity for the flaxseeds increased with increasing drying air temperature. The diffusivity dependence by temperature was described by the Arrhenius equation. It was estimated the activation energy.
Acesso aberto (Open Access)
Produção de biodiesel através da hidroesterificação do óleo de andiroba (Carapa guianensis, Aubl.) via Catalise Heterogenea Acida
(Universidade Federal do Pará, 2011-06-30) TEIXEIRA, Evilácio Luz; SOUZA, Mariana de Mattos Vieira Mello; http://lattes.cnpq.br/8882084525542926; FRANÇA, Luiz Ferreira de; http://lattes.cnpq.br/6545345391702172
The process of hidroesterification (hydrolysis followed by esterification) is constituted as an alternative to the conventional process for producing biodiesel, because it allows the use of raw materials of any content of fatty acids and moisture. Biodiesel is derived from the esterification of Andiroba oil with high content of fatty acids being used niobium oxide powder (HY-340) from Brazilian Company of Metallurgy and Mining - CBMM – as a catalyst. For the execution of experiments was used an autoclave reactor (batch). The hydrolysis reaction was conducted at 300oC, 1200 psi and molar ratio water/oil equal 20. In the esterification reactions were observed the effects of molar ratio methanol/fatty acid (1,2; 2,1 an 3,0), temperature (150, 175 and 200oC) and the concentration of catalyst (0, 10 and 20%) on conversion and initial rate of reaction. The data were conducted according to experimental design (factorial with 23 and adding 3 plants points) analyzed by the program Statistica. The conversion of esterification reaction was monitored from measurements of titrimetric acidity of aliquots removed at times of 5, 10, 15, 20, 25, 30, 45 and 60 minutes. In the experiments of esterification the highest conversion obtained was 96.1% with temperature of 200 o C, 20% m / m of catalyst and molar ratio methanol / acid equal to 3.0. Eliminating the catalyst and recital the same levels for the other two analyzed variables (temperature and molar ratio), was obtained a conversion of 95.3%, however was observed a conversion rate child, taking-if an increase of 35 minutes in the time of compared with the reaction catalyzed reaction.
Acesso aberto (Open Access)
Craqueamento termocatalítico do óleo de buriti (Mauritia flexuosa L.), óleo de palma (Elaeis guineensis) e sabões do óleo de buriti (Mauritia flexuosa L)
(Universidade Federal do Pará, 2011-06-30) SILVA, Marcilene Silva da; MACHADO, Nelio Teixeira; http://lattes.cnpq.br/5698208558551065; BORGES, Luiz Eduardo Pizarro; http://lattes.cnpq.br/8756886156388456
The present work aims to investigate the Thermocatalytic Cracking Process of the Buriti Oil ( L.), Palm Oil (Elaeis guineensis) and burit oil soap, considering the transformation of vegetable oils and soaps using the thermocatalytic cracking in biofuels, using Na2CO3 (Sodium Carbonate), CaCO3 (Calcium Carbonate), CaO (Calcium Oxide) and Acidic Zeolites (HZSM-5) as catalysts and temperatures of 420, 450 and 480 ° C. The fruit of Buriti (Mauritia flexuosa L) was collected and extracted from the pulp oil, and then this oil was characterized in relation to the Acidity Index, Saponification Number, Viscosity, Density, Refractive Index and CHN analysis. In preliminary tests it was used the refined and neutralized palm oil, so they were not characterized. Buriti soap was prepared in the laboratory with potassium hydroxide and sodium hydroxide and stored for thermal pyrolysis. The catalysts were also characterized in relation to Infrared, Nuclear Magnetic Resonance of 29Si and 27Al, XRay Diffraction, thermal analysis, chemical analysis and TPD of ammonia. In the process of thermocatalytic cracking the liquid products produced were analyzed regarding the parameters: yield, acidity index, infrared spectrum, NMR and CHN analysis and then were characterized in relation to density and kinematic viscosity. However, regarding the level of acidity of the liquid products, only basic catalysts produced cracked with acceptable values for use as fuel. From the results it was verified the efficiency of catalysts in which the sodium carbonate catalyst gave products with low acidity and good characteristics for use as fuel.
Acesso aberto (Open Access)
Estudo do processo de salga e secagem de camarão (Litopenaeus vannamei) cultivado no estado do Pará
(Universidade Federal do Pará, 2011-08-10) CORREA, Ana Cristina Leite; CORRÊA, Nádia Cristina Fernandes
We conducted the study of two forms of food preservation, salting and drying, the shrimp come from cultivation in the state of Pará. The salting process was conducted in brines with 36% concentrations m/m at 80°C and 38% m/m 100°C, using the shrimp in natura in shell and shelled, with and without agitation to evaluate the influence of these variables in the process. The drying process was carried out in the pre-cooked and salted shrimp at “Fazenda Nossa Senhora de Fátima”, in the municipality of Curuçá/Pará, at temperatures of 60°C, 80°C and 100°C. Regarding the treatment of salting, the factors that most influenced the process were the concentration and agitation; as the drying process, there was less drying time for the 100°C temperature. It proposed a mathematical model of the salting process from Fick's Law. The best fit for the process was carried out with the shrimp headless, shelled, with shaking (R2 = 0.99), effective diffusivity values ranged from 0,9x10-8 the 2,0x10-8. The kinetics of shrimp drying was set with models of Henderson and Pabis, Midilli et al., Newton, Page and Wang and Singh. The Midilli et al. model showed the best fit to the kinetic data drying shrimp at temperatures of 80ºC and 100ºC.
Acesso aberto (Open Access)
Estudo da influência da granulometria no comportamento reológico de polpa de bauxita e no fator de atrito
(Universidade Federal do Pará, 2011-09-14) BRUM, Sebastião Martins; SOUZA, José Antônio da Silva; http://lattes.cnpq.br/6157348947425968; MACÊDO, Emanuel Negrão; http://lattes.cnpq.br/8718370108324505
This paper presents studies of the rheological characterization and determination of friction factors in three bauxite slurries originating in Miltonia Mine, Paragominas - Para, resulting from operating conditions with different degrees of grinding. Thus, the basic difference between them lies in the size distribution. The goal is to make a proposal to revise the specification of the product particle size (for the bauxite slurry pipeline), allowing a comparison with the slurries of the project (pilot plant) and the current operation (processing plant) and the response to changes, especially, viscosity and friction factors. The slurry proposal incorporates a higher percentage of fines (<10 microns) compared with other slurries. The benefits can earn recovery with the incorporation of this portion of fines, which currently is discarded to the tailings pond. The material was characterized by size analysis of the series Tyler, physical and physical-chemical, electron microscopy (SEM) and X-ray spectrometry energy dispersive (EDS). Testes were conducted in coaxial cylinder viscometer, Searle type, in order to determine the rheological behavior of these slurries, depending on the size distribution and varying the concentration of solids. The rheological properties were measured viscosity, yield stress and also behaviors that show the dependence of viscosity with the time of application of a constant shear rate, verifying through the hysteresis curve, the presence or absence of thixotropy and reopexia. The experimental results showed that for the slurries tested, the particle size and solids concentration are important parameters in determining the viscosity. Tests with these three bauxite slurries of different sizes, were performed at predetermined concentrations, to determine the model whose rheological parameters showed the best correlation coefficients (R2), and the best fits were found using the Herschel-Bulkley model. The friction factors were obtained for formulations involving a logarithmic relationship, using the Law of the Wall as a method of obtaining these expressions apply to non-Newtonian viscoplastic fluid, and compared with those calculated by Dodge and Metzner correlation and found that in general there is agreement between the model studied in the three slurries. The factor analysis of friction in the concentration of 50% solids, which is the concentration of pumping by pipeline, shows that the behavior of the slurries studied is similar, with the best settings for the range from 10,000 to 100,000 Reynolds (average work range for the turbulent flow of the ore pulp, homogeneous and heterogeneous).
Acesso aberto (Open Access)
Adsorção de cromo hexavalente por carvão ativado granulado comercial na presença de surfactante aniônico (LAS)
(Universidade Federal do Pará, 2011-09-22) SILVA, Maria Vitória Roma da; CARVALHO, Samira Maria Leão de; http://lattes.cnpq.br/6192858937057152
The hexavalent chromium removal from solutions of anionic surfactant (LAS) by granular activated carbon (GAC) commercial was studied. At CAG characterization was used ASTM standard method (Sauter mean diameter, dDMS e pH) and method BET (S, specific surface area). Adsorbent surface group and PCZ were determined by the method of Boehm and potentiometric titration, respectively. The adsorbent characterization results: dDMS=2.4 mm, pH=9.0,S=677.4 m²/g; basic groups (70%) compared with the acidic groups and PCZ in the range (4.8 – 8.6). Tests of adsorption of the surfactant LAS were carried out in shaker (140 rpm/24 h./27ºC), 2.0 g CAG/50 mL, the LAS concentration were determined by methylene blue standard method. The removal results versus initial concentration and removal versus time of all LAS concentrations were more than 99%. The adsorption of Cr(VI) (5 – 20 mg/L) were carried out in thermostatic bath (140 rpm/27ºC); 2,0 g CAG/50 mL; 1 and 24 hours of processing; without and with addition of surfactant (70, 140, 210, 280, 350, 533 and 700 mg/L). The initial e residual concentrations of metal were determined by 1,5-diphenylcarbazide colorimetric method. The metal removal without the addition of LAS was not satisfactory values were obtained, around 15%. The metal removal with surfactant reached values, around 70% to the lowest metal concentration (5 mg/L) and between (58-65%) for the other concentrations.
Acesso aberto (Open Access)
Análise experimental do comportamento fluidodinâmico e da secagem de sementes de linhaça (Linum usitatissimum L.) em leito de jorro
(Universidade Federal do Pará, 2011-09-30) SANTANA, Elza Brandão; PINTO, Cláudio Roberto Orofino; http://lattes.cnpq.br/4833991906165550; COSTA, Cristiane Maria Leal; http://lattes.cnpq.br/0581730621014796
Flaxseed is the seed of the flax plant (Linum usitatissimum L.) is polymorphic native flax, and is considered one of the six plants currently recognized by the National Cancer Institute of the United States (U.S. National Cancer Institute - NCI) for their properties specific anti-cancer. Part of this recognition should be the remarkable characteristic of being the richest source of lignin precursors (vegetable steroid action analogous to the mammalian estrogen) in the human diet. The variety used in this work was the "Linseed" brown and objective of this study was to analyze the fluid-dynamics of spouted bed. The fluid-dynamics was defined by the measurements of the bed pressure drop as a function of the flow rate for different seeds loads, so getting information to determine parameters related to the process, such as: minimum spouting velocity, maximum pressure drop, stable spout pressure drop and minimum spouted pressure drop. These values were compared with the values obtained by empirical equations found in the literature. It was also studied the drying of raw material, through a full factorial design 22 with com three central point and the statistical analysis of the results were realized and the effects of independent variables spouting air temperature (Tg) and time (t) on the responses humidity ratio (Xr, adim.), germination (G, %) and germination speed index (GSI, t-1) were evaluated. The optimal operational point was determined as function of the entrance variables applying the concept of global desirability. The kinetics of drying was performed at temperatures of 45, 55 and 65 °C, and the Midilli et al. model showed the best fitting to the experimental data. For the fluid-dynamic parameters showed that the correlation of Gorshtein and Mukhlenov (1965) showed the lowest deviations for minimum spouted pressure drop and pressure drop in the steady spouted, Abdelrazek (1969) showed the smallest deviation to the minimum spouting velocity and Pallai and Németh (1969) described adequately the maximum pressure drop. It was observed that the mass of seeds processed and air-spouted temperature exerted a significant influence on fluid-dynamic. Based on the statistical analysis of experimental noticed that all variable Tg e t are statistically significant for the responses: humidity ratio, germination and germination speed index, proposing models representative of these parameters with the presence of curvature, obtaining the coefficient of determination (R2) greater than 99 %.
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)
Estudo hidrometalúrgico de compostos de titânio proveniente do resíduo do processo Bayer
(Universidade Federal do Pará, 2012-03-28) QUARESMA, Danielly da Silva; SOUZA, José Antônio da Silva; http://lattes.cnpq.br/6157348947425968
Studies performed in the Bayer process residue, red mud, for recycling this material has been intensified by their physicochemical characteristics. The residue has several oxides, these stands out the iron oxide content above 30% by weight and titanium oxide at concentrations above 5% by weight. This work studies the possibility of extracting iron oxide, aiming at concentration of titanium compounds. The extraction was carried through process of calcination of red mud at 900°C followed by acid leaching with concentration of H2SO4 at 20% and 30% by volume at 60°C, 80°C and 90°C, with removal of an aliquot every 30 minutes. During the leaching process, there was intense extraction of iron compounds, resulting in an increased concentration of titanium at the red mud. This was found in all experiments, especially those which were performed at 90°C and H2SO4 at 30% v/v, where was a extraction of 95% iron and concentration of up to 14% titanium considering the global mass balance. From the data obtained, the red mud becomes an interesting material to be used as an alternative source of minerals titanium, which are found in nature with a percentage of around 8%.
Acesso aberto (Open Access)
Estudo eletroquímico de ligas metálicas alumínio-silício em meio ácido
(Universidade Federal do Pará, 2012-03-30) SANTOS, Luana Santana dos; CARDOSO FILHO, José Carlos; http://lattes.cnpq.br/7033790503322903
The alloys based on aluminum-silicon have low specific weight, good mechanical strength and corrosion resistance, have been widely used as substitutes for some ferrous alloys in manufacturing parts for various industries. In this research we studied the electrochemical behavior of aluminum and aluminum-silicon alloys 0.3 and 0.7% by mass in electrolytes sulfuric acid and hydrochloric acid, both at 0.1 mol/L. The results of electrochemical techniques showed that the Si caused a shift to more positive values corrosion potential was observed a region of passivity anodic curves of the electrodes in sulfuric acid, this phenomenon was not observed in hydrochloric acid. The Nyquist diagrams show two arcs, a capacitive region of high frequencies related to the formation of the layer oxidizes and an inductive at low frequencies attributed to adsorption of anions on the metal surface, the similarities in the diagrams show that the electrochemical phenomena are identical and independent addition of Si. The impedance diagrams also showed low polarization resistance of the alloys Al-Si. Considering only the electrochemical studies it can be stated that the electrodes did not show significant differences between themselves and susceptibility to corrosion in these acidic solutions does not imply a negative feature to your application.
Acesso aberto (Open Access)
Produção de carvão ativado a partir da biomassa residual da castanha do Brasil (Bertholletia excelsa L.) para adsorção de cobre (II)
(Universidade Federal do Pará, 2012-09-20) MELO, Selma dos Santos; SILVA, Denilson Luz da; http://lattes.cnpq.br/4241759369873376
Activated carbon was produced from the Brazil nut bark (Bertholletia excelsa l.) to be used in the cooper (II) removing, in adsorption process in bath system. The bark is a waste material from the chestnut improvement which was collected, selected, washed in running water and then it was dried up in stove at 150 °C in 24 h. The carbons were charred at 400 °C for 3h and thermally activated at 800 °C in 1, 2 and 3 hours time when they received its encodings CA1, CA2 and CA3 respectively. Then they were characterized as: the specific superficial area, volume and pores size, X-ray diffraction, scanning electron microscopy (SEM) coupled to EDS (energy dispersive X-ray system) and Fourier transformed infrared spectroscopy FTIR). Preliminary tests were performed to assess the carbon efficiency as cooper (II) removing in synthetic solution of 50 mg L-1 initial concentration. As the results were satisfactory to CA1, CA2 and CA3 (93,43, 97,23 and 96,92 % to those carbons), decided by what had higher removing percentage of. The CA2 was produced and characterized as: the real and apparent densities, porosity in fixed bed, pH, moisture (wet basis), ashes, fixed carbon and functional groups by Boehm method. There were preformed tests to determine the cooper (II) efficiency removing concerning the carbon particle diameter influence, pH of the solution, contact time influence and variation of the initial concentration. The results of higher removing percentage were to diameter 0,595≤D≤1,19 mm, pH 5,09, in time of 5 min and concentrations of 50, 100 e 150 mg L-1. The adsorption kinetic study that best fit according to data was pseudo-second order model. The experimental data that presented good fit according to mathematical models of Langmuir and Frendlich isotherm. In this sense, was obtained activated carbon at a low cost from the Brazil nut bark which one showed a good efficiency in cooper (II) removing process and also allowing the using in the effluents treatment.
Acesso aberto (Open Access)
Caracterização e proposta de tratamento de lixiviados de resíduos de madeira
(Universidade Federal do Pará, 2012-09-24) ALMEIDA JÚNIOR, Walter Figueiredo de; SILVA, Denilson Luz da; http://lattes.cnpq.br/4241759369873376
This is a characterization study and proposal for treatment of woodwaste leachate produced in laboratory. Woodwaste leachate or stormwater runoff or log yard runoff are generated when wood waste resulting fi-om the manufacturing process, are arranged inappropriately, making the interaction with water, generally climate rainfall, resulting in a dark colored liquid which can contam n a number of components with the potential negative impact on aquatic environments. The effluent generated in the laboratory was studied by two separate experiments. In Experiment A, in polyethylene bottles, were mixed water and sawdust in proportion 9:1, in an open system and room temperature for 90 days. At times 0, 1, 5, 10, 20, 30, 45, 60, 75, 80 and 90 days, the solution was filtered and brought to the laboratory for analysis. In Experiment B, stored in a plastic container (bucket type) about 5 kg of sawdust, where the bottom was adapted a drain to collect effluent. This system was exposed to sunlight and rainfall climate, so as to simulate the minimum conditions for generation ofleachate fi-om a waste pile of wood in the real case. In both observed the generation of a liquid amber beige to dark, strong characteristic odor, slightly acidic (pH 5.53 to 6.97), high oxygen demand (BOD 17 — 310 mg.L-1; COD 857 — 3161 mg.L-1; DO 0.63 — 5.56 mg.L-1), high charges of organic matter (TC 170.93 — 425.19 mg.L-1, TOC 167.66 — 415.66 mg.L-1 and TIC 2.22 — 34.05 mg.L-1), high solids concentrations (SS 10 — 23 mL.L-1; TSS 463 — 1330 mg.L-1; TDS 31 — 640 mg.L-1 and turbidity 10.0 — 638.5 UNT). Due to these characteristics has been proposed a physicochemical treatment for runoff produced by combining the processes of coagulation/flocculation and oxidation with potassium permanganate, which resulted, respectively, in the removal of 20.95% and 88.53 % of COD, 98.18% and 43.31% of color, 40.45% and 98.16 of turbidity, 65.71% and 100% of TSS, per process. The overall removal efficiency of the proposed treatment was 90.93% of the values of COD, 98.97% in true color values, 98.90% of turbidity and 100.00% values of TSS.
Acesso aberto (Open Access)
Estudo da utilização de polímeros naturais como auxiliares de floculação no tratamento de água para fins industriais
(Universidade Federal do Pará, 2012-09-27) SILVA, Juliane da Silva e; SILVA, Denilson Luz da; http://lattes.cnpq.br/4241759369873376
This work is to evaluate the effectiveness of new alternatives for use with natural species of okra (Abelmoschus esculentus) seed angico red (Anadenanthera peregrina (L.) Speng) and seed-eye dragon (Adenanthera pavonina L.) also known as ‘falso angico’, sprayed with a particle size of 0.074 mm, sieving for water treatment as natural polymers, helping the flocculation on removal of main parameters in turbidity and color through tests in the scanner equipment using Jar Test static bench adding a chemical coagulant (aluminium sulfate). The powder of polymers were obtained after washing, drying, crushing, grinding, sieving, and used in the coagulation process, flocculation and sedimentation to test the efficiency of each one, when used alone and when used in conjunction with the chemical coagulant, followed by the analysis of physical-chemical parameters pH, turbidity, apparent color, true color and temperature. The results showed that the polymer of okra presented better efficiency in removing turbidity and color compared to the same doses used with other polymers considered and when reducing the dosage of coagulant used in conjunction with the polymers, it was observed a great removal of turbidity, especially with the conjunction of coagulant and polymer of okra, with the removal efficiency of 94% of turbidity and 98% of color with optimum dosage of okra equal to 1.0 mg/L and coagulant equal to 10 mg/L. Therefore it is possible to reduce the dosage of the coagulant when used in conjunction with the auxiliary flocculation, as the polymer of okra can be used for water treatment and facing the possibility of multiple economic and ecological uses in industry.
Acesso aberto (Open Access)
Modificação da superfície de carvão ativado comercial (CAG) para a aplicação na adsorção de benzeno e tolueno
(Universidade Federal do Pará, 2012-09-28) LOPES, Anna Sylmara da Costa; CARVALHO, Samira Maria Leão de; http://lattes.cnpq.br/6192858937057152; BRASIL, Davi do Socorro Barros; http://lattes.cnpq.br/0931007460545219
In this work they were studied the characteristics of surface of CAG commercial in natura (CA-1) and treated for (HNO3) (CA-2) and their applications in the adsorption of benzene and tolueno. Characterization of the adsorventes: specific superficial area - SBET and distribution of pores (adsorption of N2/77 K), pH (norm ASTM D3838-05), functional groups of surface (FTIR and method of Boehm). Adsorption tests were performed in batch system and fixed bed column (25 ° C/140 rpm/25 minutes), where the samples were quantified by gas chromatography with headspace extraction by EPA method 0010. The SBET and the average volume of the pores of the adsorbent CA-2 decreased with relation to the values of CA1 as well as the pH. There was an increase of acidic functional groups determined by the method Boehm of the adsorbent CA-2 in relation to CA-1, which was confirmed by determining FTIR, in which the intensity of the absorption bands were more intense for CA-2. Test data were fitted satisfactorily by kinetic mathematical model of pseudo-second order, based on statistical tests applied, with statistically significant differences between the treated adsorbent (CA-2) and in natura (CA-1). Assays were performed equilibrium adsorption, and the results correlated by the Langmuir isotherm, with satisfactory response for that model. From the adsorption system in a fixed bed column and considering the highest volumetric flow (Q = 100 mL / min) used in this system yielded the most important results of adsorption of benzene and toluene using (CA-2) as adsorbent.
Acesso aberto (Open Access)
Avaliação do processo de produção de etanol pela fermentação do caldo de mandiocaba (Manihot esculenta Crantz)
(Universidade Federal do Pará, 2013-02-28) SOUZA, Leiliane do Socorro Sodré de; FRANÇA, Luiz Ferreira de; http://lattes.cnpq.br/6545345391702172
The physico-chemical characteristics identified at sweet cassava root, was: moistures (%), fiber (%), protein (%), ash (%), total lipids (%), reducing sugars and total reducing sugars (%); the sap extract from sweet cassava root was characterized by pH, soluble solids (%), glucose and titratable acidity. This study used the yeast Saccharomyces cerevisiae PE-2. Was realized 15 tests that followed the conditions determined by the experimental design of Box- Behnken, with 3 independent variables: temperature (oC) (X1), pH (X2) and concentration of inoculum (g/L) (X3). The statistical analysis was performed with p>0,05. Through the analysis of variance (ANOVA) was proposed a second order polynomial model to the alcohol content (ºGl), and by analysis of response surfaces it was determined the optimum condition to the fermentation of sap extract from sweet cassava root without addition of nutrients, on original substrate concentration of it (6,46 g/L): 28ºC (temperature), 4,88 (pH) and 10 g/L (inoculum concentration). Under these conditions a test was conducted, which aimed to raise the curves of cell growth (yeast), CO2 production, consumption of sugars and ethanol production, to better understand the process of fermentation broth of sweet cassava. Through the cellular growth curve was determined the duration of the exponential phase, using the method of linear regression; this step in this study occurred at different time intervals. The value found to μm was 0,05 h-1.