Artigos Científicos - FEQ/ITEC

URI Permanente para esta coleçãohttps://repositorio.ufpa.br/handle/2011/2456

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Síntese hidrotérmica de zeólitas a partir de cinza volante de carvão mineral: aplicação na adsorção de íon amônio
(Universidade Federal do Pará, 2018-10) MAUES, Tamiris Cristina de Lima; ROCHA JUNIOR, Carlos Augusto Ferreira da; SOUZA, José Antônio da Silva
Fly ash is the main industrial waste generated by coal in steam and power plans. In Brazil, 1,4 million tons are produced every year. These ashes can be converted into zeolite products by alkaline hydrothermal treatment. The main objective of this paper was to induce this reaction which produces only zeolitic crystalline phases for ammonium ion absorption. So, some syntheses were done by different hydrothermal method (classical or two stages), work time (24 or 30 h) and many NaOH bulks. The characterization of ash (in natura and calcined) and products was performed by X-ray diffraction method, scanning electron microscopy and, in some cases, differential thermal and thermogravimetric analysis The product by two stages method was used in ammonium ion absorption in solution at Sips Mathematic Model: the highest capacity of 2,71 mg.g-1.
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Comportamento higroscópico de partes aéreas de pimenta-de-macaco (Piper aduncum L.)
(2015-04) SILVA, Carolina de Lourdes Oliveira Cruz e; FARIA, Lênio José Guerreiro de; COSTA, Cristiane Maria Leal
Desorption isotherms of monkey pepper were determined by static gravimetric method at temperatures 35, 45, and 55 ºC, over a relative humidity range of 5.5-81%. Three mathematical models were applied to analyse the experimental data. The modified GAB model showed the best adjustment of the experimental data. The isosteric heat and differential entropy were determined by applying Clausius-Clapeyron and Gibbs-Helmholtz equations, respectively. The isosteric heat and the entropy of desorption isotherm presented similar behavior. The enthalpy-entropy compensation theory was applied to the isotherms, indicating that the aerial parts desorption mechanism are enthalpy-controlled.
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Inibição e reversão da agregação plaquetária de eqüinos in vitro com o uso de ketoprofeno, fenilbutazona e flunixim meglumine
(2009-10) LEME, Fabiola de Oliveira Paes; WURZINGER, Laurenz; ALVES, Geraldo Eleno Silveira; BICALHO, Adriane Pimenta da Costa-Val; BARBOSA, Marcos Pinott; PAES, Paulo Ricardo de Oliveira; OLIVEIRA, Marcos Enê Chaves
Several diseases may lead to platelet pre-activation and hypercoagulability states in horses. The activity of many drugs against platelet aggregation may, not only contribute to the evaluation of a disease but also its response to the therapy. With the aim to study in vitro prevention and reversion of platelet aggregation, the non steroidal anti-inflammatory drug (NSAID): ketoprophen, phenylbutazone and flunixin-meglumin were evaluated. The comparison demonstrated that phenylbutazone and ketoprophen prevented platelet aggregation induced by ADP better than flunixin-meglumin, in a superior manner to the monoclonal antibody Reopro, and in a better way than the membrane receptor blockers Ro-438857 and RGDS. The reversion of platelet aggregation demonstrated that even phenylbutazone or ketoprophen have a dose-dependent effect.
Acesso aberto (Open Access)
Investigação do processo de corrosão causado pela polpa de bauxita em mineroduto de aço carbono
(2015-03) SANTOS, Marcelo Costa; PINHEIRO, Clairon Lima; CARDOSO FILHO, José Carlos de Araújo
The corrosion caused by the ore slurry transported plays a fundamental role in the lifetime of a pipeline. Thus, the corrosion of API 5L-X70 carbon steel was investigated using process water and bauxite pulp (5% w./v.) as solution and electrochemical techniques. The results of open circuit potential (OCP), polarization and electrochemical impedance spectroscopy (EIS) showed that presence of bauxite caused changes when it compared to water process results and the corrosion rate increased in the bauxite presence. The micrographs of specimens surface obtained by scanning electron microscopy (SEM) showed cracks formation in the oxide in the metal surface and this phenomenon may be responsible for increased corrosion in bauxite presence. The methodology described in this work show to be useful for the investigation of corrosion in pipelines.
Acesso aberto (Open Access)
Collecting and evaluation of germplasm of spiked pepper from Brazilian Amazon
(2010-06) GAIA, José Maria Demetrio; MOTA, Milton Guilherme da Costa; CONCEIÇÃO, Carmen Célia Costa da; MAIA, José Guilherme Soares
Spiked pepper (Piper aduncum L.) is an aromatic plant species with high essential oil production. It is a species that occurs abundantly in the Brazilian Amazon. Its essential oil has exploitable biological properties in the human health and agriculture. Aiming to study its germplasm toward future use in genetic breeding programs, collecting was carried out (inflorescences, cuttings, leaves and thin branches) in ten provenances from the Brazilian Amazon. Twelve morphoagronomic traits were determined to take the data: number of leaves by branch, length of leaf, width of the leaf, circumference of the older branch, height of the plant, number of orthotropic branches, number of plageotropic branches, length of the internodes, number of spikes per branches, yielding of oil, content and production of dillapiole, as well as data on the environment and populations of spiked pepper. The inflorescences and cuttings were encoded and sent for the Federal Rural University from Pará State (UFRA), Brazil, for propagation. The leaves and thin branches were sent for the Emílio Goeldi Museum, from Pará State (MPEG) for extraction of essential oil (hydrodistillation). Estimators of amplitude of variation, mean, standard deviation and coefficient of variation were utilized to study the phenotypical variability. The morphoagronomic traits of largest variability were number of orthotropic branches, number of spikes per branch, circumference of the older branch and the content and production of dillapiole. This species has adapted to many different environments of vegetation, soil, climate, relief and drainage becomming easy the domestication and cropping. There is morphoagronomic variability pleasing the selection and genetic breeding.
Acesso aberto (Open Access)
Morphologic characterization of spiked pepper's germplasm
(2011-06) GAIA, José Maria Demetrio; MOTA, Milton Guilherme da Costa; CONCEIÇÃO, Carmen Célia Costa da; MAIA, José Guilherme Soares
Spiked pepper is a plant species with properties that allow the development of natural agrochemicals and medicines, showing large potential of use by humanity. With aim to ascertain the phenotypical variability, 41 parentals were analyzed, sampled in the States of Pará and Amazonas. Principal Component analysis and Jolliffe's criterion were utilized for discarding of variables, subsidized by the Pearson's Correlation. It took seven components to explain 80% of the variation. The essential oil yield and number of leaves per branch were suggested to be discarded because they are the characteristics that have contributed least to the total variance. The 3D scatter diagram constituted a relatively homogeneous and continuous clustering, identifing a divergent pair: PA-020 (Marabá-PA) and PA-035 (Santa Isabel-PA). The analyzed traits have variability potentially able to discriminate the parentals, whereas 83.3% of such traits can be used for this purpose. The divergent genotypes identified on 3D scatter diagram analysis can be used in breeding programs for the development of superior genotypes. A comparison with preexisting molecular data of some genotypes permited to conclude that there was one certain agreement degree between morphological and molecular characterizations and that molecular characterization presented higher discriminatory power, using a smaller number of genotypes, identifying dissimilar genotypes and clusters, although analyzed by different multivariate statistic methods.
Acesso aberto (Open Access)
Síntese e caracterização de argila esmectita Zn-estevensita
(2014-06) HILDEBRANDO, Edemarino Araujo; VALENZUELA, Maria das Graças da Silva; NEVES, Roberto de Freitas; DIAZ, Francisco Rolando Valenzuela
Clay of the smectite group was successfully obtained at a low temperature hydrothermal processing using sodium metasilicate, zinc nitrate and urea as precursor materials. During the synthesis step, the molar composition of the mixture and the temperature remained constant varying the reaction time. The synthesized samples were characterized by X-ray diffraction, scanning electron microscopy, diffuse reflectance Fourier Transform infrared spectroscopy, differential thermal analysis and thermogravimetry, cation exchange capacity (CEC) and BET surface area measurements. The results show that in the methodology utilized is obtained Zn-stevensite with specific surface area of 171.6-203.4 m2/g and good crystallinity as present single phase in the reaction product after static synthesis at 90 ºC for 44 to 138 h, indicating that, the increased synthesis time is an important parameter for crystallization process of the clay.
Acesso aberto (Open Access)
Alumina para utilização cerâmica, obtida a partir do rejeito de beneficiamento de caulim
(1997-12) FLORES, Silvia Maria Pereira; NEVES, Roberto de Freitas
The kaolin processing for paper covering produces a great volume of residues formed primarily by kaolinite claymineral, here the starting material for the synthesis of ammonium alumen aiming to obtain free sodium alumina with fine grade for ceramic manufacturing. The synthesis process to obtain ammonium alumen consisted of the following procedures: residues calcination and sulphuric leaching of metakaolinite followed by neutralization/crystallisation of aluminum sulphate solution with ammonium hydroxide concentrated solution. The effect of calcination temperature (650 °C, 700 °C and 750 °C), calcination time of residues (30 min, 60 min and 120 min), sulphuric acid concentration as well as leaching temperature (70 °C, 80 °C and 90 °C) on the kinetics of aluminum leaching were studied. The influence of pH on ammonium alumen crystallization was also studied. Data on chemical analysis, XRD, DTA, TGA and granulometry of the material utilized and synthesized are presented and discussed.
Acesso aberto (Open Access)
Desorption of heavy metals from ion exchange resin with water and carbon dioxide
(2006-06) SILVA, Denilson Luz da; BRUNNER, Gerd
Adsorption and regeneration of ion exchange resins were studied using a subcritical solution of a CO2-H2O mixture and a fixed bed column. The commercial Amberlite IRC-50/IRC-86 cation exchange resins and Amberlite IRA-67 anion exchange resin were tested for heavy metals (Pb, Cu, Cd) adsorption from a solution with different initial metal concentrations at different temperatures. After adsorption, the loaded resins were regenerated with water and carbon dioxide at different temperatures and a pressure of 25 MPa. The efficiency of the IRC-50 resin was lower than that of the IRC-86 resin for the adsorption of metals like Cd, Cu and Pb. Results obtained for desorption of these metals indicated that the process could be used for Cd and in principle for Cu. Sorption of metal ions depended strongly on feed concentration. Mathematical modeling of the metal desorption process was carried out successfully as an extraction process. For this purpose, the VTII Model, which is applied to extraction from solids using supercritical solvents, was used in this work.
Acesso aberto (Open Access)
On the prediction of pickup and saltation velocities in pneumatic conveying
(2014-03) GOMES, Luiz Moreira; MESQUITA, André Luiz Amarante
This paper presents a comparative study of the critical pickup and saltation velocities of particles in horizontal pipelines for pneumatic conveying design. A comparative study is performed using different existing correlations in the literature for the determination of the minimum velocity of transport as a function of the particle and pipe diameter, particle density, solid mass flow rate and particle sphericity. Their limitations and difficulties in predicting those critical velocities are analyzed. For the pickup velocity, an experimental study was also carried out in order to support the analysis. Recommendations are presented on the use of such correlations.
Acesso aberto (Open Access)
Obtenção e caracterização de carvão ativado de caroço de buriti (Mauritia flexuosa L. f.) para a avaliação do processo de adsorção de cobre (II)
(Instituto Nacional de Pesquisas da Amazônia, 2013-03) PINTO, Marcos Vinicios de Souza; SILVA, Denilson Luz da; SARAIVA, Augusto Cesar Fonseca
In the Amazon region some industries discharges copper into watercourse that in high concentrations is toxic to the biota. The removal of copper from industrial effluent is performed by several processes such as adsorption. This work shows the result of copper (II) adsorption on activated carbon obtained from buriti kernel, carbonized at 400 °C and activated at 900 °C. The activated carbon was characterized according to specific area, pore size, apparent and real density, porosity, scanning electron microscopy, ash content, pH, moisture, fixed carbon and surface functional groups. The study of adsorption equilibrium evaluated the influence of the coal particles diameter, contact time adsorbent/adsorbate, pH and copper (II) solution initial concentration on copper (II) remotion. The results showed a higher removal efficiency of copper (II) to the diameter D < 0.595 mm, contact time of 300 minutes, pH of 4.01 and the copper (II) initial concentrations of 50 and 80 mg L-1. The mathematical model of Langmuir was the best fit to the adsorption equilibrium data. From the contact time of 15 minutes, all the equilibrium concentrations were below the allowed maximum of 1,0 mg L-1 provided by law for discharging effluents into receiving bodies.
Acesso aberto (Open Access)
Rosewood (Aniba rosaeodora Ducke) oil in broiler chickens diet
(2014-03) AGUILAR, César Augusto López; LIMA, Kedson Raul de Souza; MANNO, Maria Cristina; MAIA, José Guilherme Soares; FERNANDES NETO, Dário Lisboa; TAVARES, Fernando Barbosa; ROQUE, Thiago José Lima Ribeiro; MENDONÇA, Rita de Cássia Almeida de; CARMO, Elder Santana Natividade do
A study was conducted to evaluate the effects of Rosewood oil (RO) on performance, carcass and commercial cut yields and microbiology of the gastrointestinal tract of broiler chickens. Five hundred and forty one-day-old male broiler chicks were arranged in a completely randomized design with six treatments and six repetitions consisting of 15 broiler chicks each. The treatments were: inclusion levels of 0.00mL (0.00EO); 0.15mL (0.15 EO); 0.30mL (0.30 EO); 0.45mL (0.45 EO) and 0.60mL (0.60 EO) of RO/kg diet and control (commercial promoter virginiamycin). At 21 and 40 days old, no significant differences in body weight, feed intake, feed conversion and viability of birds were observed when comparing the controls with the different levels of inclusion of RO. The carcass yields of commercial cuts were not affected by treatments. The increased level of RO reduced the relative weight of the intestines. The broilers consuming growth promoter had the highest concentration of Escherichia coli in the intestinal contents, compared to 0.00 EO and 0.30 EO. It was concluded that, Rosewood oil does affect the performance and yield slaughter, but it does reduce the relative weight of the intestines. RO does not show a consistent antimicrobial activity in vivo against Escherichia coli.
Acesso aberto (Open Access)
Preliminary risk analysis applied to the handling of health-care waste
(2002-12) CARVALHO, Samira Maria Leão de; SILVA, Meuris Gurgel Carlos da
Between 75% and 90% of the waste produced by health-care providers no risk or is "general" health-care waste, comparable to domestic waste. The remaining 10-25% of health-care waste is regarded as hazardous due to one or more of the following characteristics: it may contain infectious agents, sharps, toxic or hazardous chemicals or it may be radioactive. Infectious health-care waste, particularly sharps, has been responsible for most of the accidents reported in the literature. In this work the preliminary risks analysis (PRA) technique was used to evaluate practices in the handling of infectious health-care waste. Currently the PRA technique is being used to identify and to evaluate the potential for hazard of the activities, products, and services from facilities and industries. The system studied was a health-care establishment which has handling practices for infectious waste. Thirty-six procedures related to segregation, containment, internal collection, and storage operation were analyzed. The severity of the consequences of the failure (risk) that can occur from careless management of infectious health-care waste was classified into four categories: negligible, marginal, critical, and catastrophic. The results obtained in this study showed that events with critics consequences, about 80%, may occur during the implementation of the containment operation, suggesting the need to prioritize this operation. As a result of the methodology applied in this work, a flowchart the risk series was also obtained. In the flowchart the events that can occur as a consequence of a improper handling of infectious health-care waste, which can cause critical risks such as injuries from sharps and contamination (infection) from pathogenic microorganisms, are shown.
Acesso aberto (Open Access)
Adsorção de cromo (VI) por carvão ativado granular de soluções diluídas utilizando um sistema batelada sob pH controlado
(Instituto Nacional de Pesquisas da Amazônia, 2009-09) SOUZA, Renata dos Santos; CARVALHO, Samira Maria Leão de; GARCIA JÚNIOR, Márcio Ronald de Lima; SENA, Rafael dos Santos Fernandes
In Amazonia, chromium is mainly used in the leather and wood industries. It is responsible for many health problems, because of its toxicity. These industries remove chromium waste by various processes, such as adsorption. This work shows the results of Cr(VI) adsorption by commercial granular activated carbon (GAC) as adsorbent from diluted solutions, and batch systems with controlled pH. The functional groups on the CAG surface was carried out by the Boehm method. In addition, effect of pH on the Cr(VI) adsorption, adsorption equilibrium, and kinetic were studied under experimental conditions (pH = 6, MA = 6g, for 90min.). On the GAC surface, carboxylic groups were found to be in higher concentrations (MAS=0,43 mmol/gCAG), which increase the Cr(VI) adsorption, principally in acidic pH values. The adsorption capacity is dependent on the pH of the solution, due to its influence on the surface properties of the CAG and different ionic forms of the Cr(VI) solutions. The adsorption equilibrium data was adjusted satisfactorily by the Langmuir isotherm (R2=0,988), favorable type. From kinetics adsorption of 20 mg/L and 5 mg/L, the results were compatible with the national legislation (Res. nº 357/05). Therefore, the experimental system using (CAG) was efficient in removing the Cr(VI) from liquid streams containing low concentrations of the metal.
Acesso aberto (Open Access)
High pressure vapor-liquid equilibria of palm fatty acids distillates-carbon dioxide system
(1997-12) MACHADO, Nélio Teixeira de; BRUNNER, Gerd
Vapor-Liquid equilibria of palm fatty acids distillates/carbon dioxide system has been investigated experimentally at temperatures of 333, 353, and 373 K and pressures of 20, 23, 26, and 29 MPa using the static method. Experimental data for the quasi-binary system palm fatty acids distillates/carbon dioxide has been correlated with Redlich-Kwong-Aspen equation of state. Modeling shows good agreement with experimental data. Selectivity obtained indicates that supercritical carbon dioxide is a reasonable solvent for separating saturated (palmitic acid) and unsaturated (oleic+linoleic acids) fatty acids from palm fatty acids distillates in a continuous multistage countercurrent column.
Acesso aberto (Open Access)
Separation of satured and unsaturated fatty acids from palm fatty acids distillates in continuous multistage countercurrent columns with supercritical carbon dioxide as solvent: a process design methodology
(1997-12) MACHADO, Nélio Teixeira de; BRUNNER, Gerd
In this work the separation of multicomponent mixtures in counter-current columns with supercritical carbon dioxide has been investigated using a process design methodology. First the separation task must be defined, then phase equilibria experiments are carried out, and the data obtained are correlated with thermodynamic models or empirical functions. Mutual solubilities, Ki-values, and separation factors aij are determined. Based on this data possible operating conditions for further extraction experiments can be determined. Separation analysis using graphical methods are performed to optimize the process parameters. Hydrodynamic experiments are carried out to determine the flow capacity diagram. Extraction experiments in laboratory scale are planned and carried out in order to determine HETP values, to validate the simulation results, and to provide new materials for additional phase equilibria experiments, needed to determine the dependence of separation factors on concetration. Numerical simulation of the separation process and auxiliary systems is carried out to optimize the number of stages, solvent-to-feed ratio, product purity, yield, and energy consumption. Scale-up and cost analysis close the process design. The separation of palmitic acid and (oleic+linoleic) acids from PFAD-Palm Fatty Acids Distillates was used as a case study.
Acesso aberto (Open Access)
Extraction of oil from pressed palm oil (Elaes guineensis) fibers using supercritical CO2
(1997-12) FRANÇA, Luiz Ferreira de; MEIRELES, Maria Angela de Almeida
Residual fibers from palm oil production are a good source of carotene, since they contain more than 5% of the original oil, with about 5000 ppm of carotenoids. As carotenoids are thermosensitive molecules, supercritical CO2 can be used for oil recovery, because this technique employs low temperatures. In this work results of oil extraction experiments from pressed palm oil fibers are shown. Fibers were from AGROPALMA, an industry which is located in Tailândia (Pará, Brazil). Extractions were carried out at 200, 250 and 300 bar and at temperatures of 45 and 55oC. Oil was analyzed by UV/vis spectrophotometry for total carotene determination. Results showed a large increase in extraction rate from 200 to 250 bar and a small variation from 250 to 300 bar. The total amount of carotenes did not increase in the course of extraction at 300 bar, but it showed a large increase at 200 and at 250 bar. Free fatty acids are present in amounts larger than those found in commercial oils.
Acesso aberto (Open Access)
Supercritical extraction of pupunha (Guilielma speciosa) oil in a fixed bed using carbon dioxide
(2000-09) ARAÚJO, Marilena Emmi; MACHADO, Nélio Teixeira de; FRANÇA, Luiz Ferreira de; MEIRELES, Maria Angela de Almeida
The pupunha (Guilielma speciosa) is the fruit of a palm tree typical of the Brazilian Northern region, whose stem is used as a source of heart of palm. The fruit, which is about 65% pulp, is a source of oil and carotenes. In the present work, an analysis of the kinetics of supercritical extraction of oil from the pupunha pulp is presented. Carbon dioxide was used as solvent. The extractions were carried out at 25 MPa and 323 K and 30 MPa and 318 K. The chemical composition of the extracts in terms of fatty acids was determined by gas chromatography. The amount of oleic acid, a saturated fatty acid, in the CO2 extracts was larger than that in the extract obtained with hexane. The overall extraction curves were modeled using the single-parameter model proposed in the literature to describe the desorption of toluene from activated coal.
Acesso aberto (Open Access)
Optimization of annatto (Bixa orellana L.) drying in fixed bed
(2000-12) FARIA, Lênio José Guerreiro de; ROCHA, Sandra Cristina dos Santos
The drying of annatto seeds (Bixa orellana L.), red piave cultivate, was studied in a fixed bed dryer. The best conditions were estimated to minimize the loss of coloring and to obtain final moisture of the seeds in appropriate levels to its conservation and maintenance of quality. The quantification of the influence of entrance variables in the final contents of bixin and moisture seeds and the identification of the optimal point was performed through the techniques of factorial design, response surfaces methodology, canonical analysis and desirability function. It was verified that the final moisture of the seeds may be estimated by a second-order polynomial model and that the final content of bixin is only significantly influenced by the time of drying being described properly by a linear model, for the seeds used in this study.
Acesso aberto (Open Access)
Alkaloids and volatile constituents from the stem of Fusaea longifolia (Aubl.) Saff. (Annonaceae)
(2005-06) TAVARES, Josean Fechine; BARBOSA FILHO, José Maria; SILVA, Marcelo Sobral da; MAIA, José Guilherme Soares; CUNHA, Emidio Vasconcelos Leitão da
A phytochemical study of the ethanol extract and an extraction of the volatile compounds, performed by means of Clevenger apparatus were carried out with the stem of Fusaea longifolia (Aubl.) Saff. (Annonaceae). The ethanol extract yielded O-methylmoschatoline, isolated for the first time in this species, and stepholidine, reported for the first time in genus Fusaea. The structural identification of the alkaloids was made based on the analysis of their NMR spectra. Through the use of GC and GC-MS, two sesquiterpenoids, a-cadinol (12.5%) and spatulenol (12.0%) were identified as the major constituents of the essential oil.