Programa de Pós-Graduação em Engenharia Química - PPGEQ/ITEC

URI Permanente desta comunidadehttps://repositorio.ufpa.br/handle/2011/2308

O Programa de Pós-Graduação em Engenharia Química (PPGEQ) do Insituto de Tecnologia (ITEC) da Universidade Federal do Pará (UFPA). Sendo aprovado pela CAPES / MEC em 1991, foi oficialmente iniciado em março de 1992.

Navegar

Agora exibindo 1 - 20 de 42

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)
Adsorção monocomponente e binária de antiinflamatórios não esteroidais (Ibuprofeno e Diclofenaco) do meio aquoso por carvão ativado de resíduos da castanha-do-Brasil (Bertholletia excelsa H.B.K.)
(Universidade Federal do Pará, 2024-09-12) SILVA, João Paulo Sousa da; VIEIRA, Melissa Gurgel Adeodato; http://lattes.cnpq.br/6611289393148830; CARVALHO, Samira Maria Leão de; http://lattes.cnpq.br/6192858937057152
Emerging contaminants (ECs) present in low concentrations have caused damage to water bodies. This study investigated the single-component and binary adsorption of sodium ibuprofen (IBU) and diclofenac (DIC) using activated carbon (AC) produced from Brazil nut shells. The single-component adsorption process of IBU and DIC by AC was denoted as (AC_IBU and AC_DIC), and the binary adsorption process was denoted as (AC_IBU+DIC). The AC was synthesized by chemical activation using phosphoric acid (H3PO4) as the activating agent. The AC was characterized through physical, chemical, and textural analyses, including moisture content, ash content, yield, Thermogravimetric Analysis/Differential Thermal Analysis (TGA/DTA), X-Ray Diffraction (XRD), Fourier Transform Infrared Spectroscopy (FT-IR), Scanning Electron Microscopy/Energy Dispersive X-ray Spectroscopy (SEM/EDS), surface pH, point of zero charge (pHPZC), Boehm titration, and nitrogen (N2) adsorption/desorption at 77 K. The AC presented moisture and ash contents of 8.62% and 4.2%, respectively. The XRD analysis confirmed the amorphous nature of the AC, while FT-IR, surface pH, and pHPZC analyses indicated its acidic nature. The specific surface area (SBET) of the AC was 1,383.624 m².g-1 , with a predominance of micropores (VMIC=77.88%). From the analysis of the Central Composite Rotational Design (CCRD), the experimental conditions for the kinetic and equilibrium adsorption tests were defined for single-component adsorption: (i) IBU (pH = 6.1; initial adsorbate concentration, C0 = 50 mg.L-1 ; adsorbent dosage, DA = 0.5 g.L-1 ) and (ii) DIC (pH = 5.5; C0 = 50 mg.L-1 ; DA = 0.5 g.L-1 ). In the single-component adsorption kinetics study, the pseudofirst-order (PFO) and pseudo-second-order (PSO) models resulted in the best fits to the experimental data for the AC_IBU and AC_DIC adsorption processes, respectively, and external mass transfer was the rate-controlling step of the processes. In the singlecomponent adsorption equilibrium study, the Langmuir, Freundlich, Sips, DubininRadushkevich, and Redlich-Peterson isotherms were investigated. The Sips and Freundlich models showed the best correlations for AC_IBU and AC_DIC, respectively. The thermodynamic parameters calculated from the adsorption isotherms showed that the AC_IBU and AC_DIC processes are spontaneous, favorable, and exothermic. The CCRD, the experimental conditions for the binary adsorption kinetics and equilibrium tests were defined: (i) AC_IBU+DIC (C0IBU = 50 mg.L -1 ; C0DIC = 50 mg.L-1 ; DA= 0.5 g.L-1 ). Binary adsorption indicated, through the calculation of the separation factor parameter, that the adsorption preference order by the adsorbent is IBU > DIC, and the interaction between the adsorbates was antagonistic. In the binary adsorption process, the PSO model was well fitted to the experimental kinetics data of IBU and DIC; the intraparticle diffusion (IPD) kinetic models and the Boyd equation were correlated with the experimental data, and external mass transfer was the rate-controlling step of the adsorption processes. The isotherms of binary adsorption (AC_IBU+DIC) at different temperatures (26 ºC, 45 ºC, and 55 ºC) showed inflection points, and after these inflection points, there was an increase in the adsorption capacity values of AC (qe). The qe values of binary adsorption (AC_IBU+DIC) were lower than the qe values of the singlecomponent adsorption processes of the adsorbates IBU and DIC. The reduction percentages of the qe values were approximately 35% to 48% for IBU and about 52% to 53% for DIC.
Acesso aberto (Open Access)
Análise experimental da secagem do corante hidrossolúvel de urucum (Bixa orellana L.) em leito de jorro
(Universidade Federal do Pará, 2016-02-15) SILVA, Adriano Gomes Paixão da; FARIA, Lênio José Guerreiro de; http://lattes.cnpq.br/7428609361678173; https://orcid.org/0000-0002-9534-9998; COSTA, Cristiane Maria Leal; http://lattes.cnpq.br/0581730621014796
The water-soluble dye annatto norbixin salt is mainly used in the pharmaceuticals industry, cosmetics and especially in industrial food sector in breads, sausages, yogurts, confectionery, pasta, cheese, sandwich cookies, juice concentrates and others. The low toxicity and its coloring ability make the annatto norbixin salt a very attractive and convenient dye, replacing many synthetic dyes. These characteristics encourage to seek ways to facilitate the use of natural dyes in the various segments of industry, as well as promoting research about obtaining in order to get a product with the desired characteristics and qualities. This work it is carried out experimental analysis of water soluble dye drying annatto (Bixa orellana L.) in spouted bed, using cassava starch as a carrier agent and particles of low-density poliestileno (LDPE) as an inert material. The extraction of the dye was carried out by immersion and agitation of annatto seeds in 5% potassium hydroxide solution. It is statistically evaluated the influence of the drying process input variables, temperature (70, 80 and 90 ° C), atomization pressure (10, 15 and 20 psi), and atomization of the suspension flow (10, 7 and 8.5 mL/min) one the response variables: efficiency (η), moisture content (U) and norbixin salt content of the dye powder (S), using Statistica®7.0 application. The estimate of the optimum condition of drying within the analyzed experimental area is determined based on the input variables applying the concept of global desirability. The conditions in this work, it was reached a optimum value of Desirability Function considered as very good and that matches the temperature of the drying air 82.6 °C, atomization pressure of 13.7 psi and flow of suspension dye 10 ml / min, generating satisfactory values for the response variables corresponding to 71.69 % yield, 0.06161 g H2O/g dry solids of moisture and 2.3605 % dye of norbixin salt powder.
Acesso aberto (Open Access)
Aproveitamento da torta de dendê (elaeis guineenses) para a produção do acetato de celulose
(Universidade Federal do Pará, 2022-06-17) MORAES JUNIOR, Elio Ferreira de; ALMEIDA, Ossalin de; http://lattes.cnpq.br/7040173036131516; HTTPS://ORCID.ORG/0000-0003-3895-0952; CHAVES NETO, Antônio Maia de Jesus; http://lattes.cnpq.br/3507474637884699; https://orcid.org/0000-0002-9730-3512
This work aimed to produce cellulose acetate (CA) from in natura palm kernel pie (TD) it was subjected to different chemical treatments: bleaching (TDB), alkaline (TDA) and alkaline followed by bleaching (TDAB). The CA was obtained from the different materials by homogeneous acetylation in the mass ratios: 1:5, 1:10 and 1:15 (acetic acid), 1:15 (acetic anhydride) and 1:0.1 (sulfuric acid). Reactions were carried out at room temperature under constant stirring (120 rpm, 24 h). The characterization was performed using scanning electron microscopy (SEM), infrared spectroscopy (FTIR) and nuclear magnetic resonance (1H and 13C-NMR) techniques. The degree of substitution (GS) was determined by titration with 0.25 mol.L-1 sodium hydroxide solution, being confirmed by FTIR and 1H and 13C NMR with different GS. The CA synthesized from the combination of pre-treatments presented DS of 2.81 (TDAB5), 3.02 (TDAB10) and 3.07 (TDAB15), being, therefore, it characterized as cellulose triacetate, corresponding to the yield values (m/m) of 50.45%, 65.5% and 97.21%. By analyzing the results, TDAB15 was the best condition for obtaining cellulose acetate from palm kernel cake.
Acesso aberto (Open Access)
Aproveitamento de resíduos sólidos da mandiocaba (Manihot esculenta Crantz) para o desenvolvimento de bioadsorventes
(Universidade Federal do Pará, 2023-07-10) DIAS, Rafael Silva; MARTELLI, Marlice Cruz; http://lattes.cnpq.br/1213009262936026; BRASIL, Davi do Socorro Barros; http://lattes.cnpq.br/0931007460545219; https://orcid.org/0000-0002-1461-7306
The chemical contamination of water by dyes resulting from the disposal of industrial effluents triggered the need to develop technologies to remove such pollutants. Occurring naturally in the Amazon region, cassava differs from other cassava varieties in that it has high humidity and low starch yield. As part of a project on cassava technologies, this study analyzed the best conditions for the production of activated carbon from cassava solid waste for the adsorption of methylene blue dye. The Box-Behnken experimental design was used to determine the optimal production conditions. First, a physical-chemical analysis of the precursors was carried out, then 30 coal samples were produced according to the experimental plan. The maximum adsorbed amount and percentage of removal were determined under finite bath conditions, at a concentration of 120 mg/L and with 0.01 g of coal sample. The best conditions of temperature, acid concentration and heat contact time were observed at 600 ºC, 25 % and 3 h for peel and 600 ºC, 10.2 % and 3 h for pulp. These samples were subjected to physical-chemical and morphological characterization analyzes using scanning electron microscopy and Fourier transform infrared. For the adsorption kinetics tests, the models that best fitted the experimental data were intraparticle diffusion for shell and pulp coals, and for the adsorption equilibrium tests, the Freundlich and Langmuir models best fitted the experimental data for shell and pulp, respectively. Analysis of the adsorbents reveals a lower concentration of functional groups, however, in the pulp adsorbent, the loss of functional groups related to groups containing oxygen can be observed, which may help explain the lower adsorption capacity observed for pulp adsorbents. The activated carbons produced from the solid residues of cassava roots (pulp and peel) showed that, under the conditions used in this work, they can be applied as effective bioadsorbents in the removal of methylene blue in aqueous solution.
Acesso aberto (Open Access)
Ativação alcalina para a produção de geopolímeros a partir de resíduo industrial
(Universidade Federal do Pará, 2018-02-02) BRITO, Woshington da Silva; SOUZA, José Antônio da Silva; http://lattes.cnpq.br/6157348947425968
The sustainable construction of the future, and has low energy consumption and greenhouse gas emissions must also adopt the principle of reuse of wastes impacting the environment generated by the productive chain. The aluminum production chain has as one of the leading waste impact on the environment the gray generation. The present study focused on the research and development of a cement-based material. Refers to an inorganic polymer, formed by the activation of amorphous aluminosilicates (Al2O3. SiO2), which react in a strongly alkaline medium, called geopolymer. As a raw material furnace fly ash, mineral residue from the combustion of the boilers of the company of the municipality of Barcarena-PA; As a source of aluminosilicate, and the kaolin that underwent the process of burning at 800 ºC that became metakaolin; And the alkaline medium of sodium silicate (Na2SiO3) and sodium hydroxide (NaOH), used as activators. As fly ash partially crystallizes during burning and loses some of its amorphous state, so are its reactive properties to chemically combine during the geopolymerization reaction are reduced. To increase reactive properties of fly ash and added metakaolin. As the main analyzes, no X-ray diffraction (XRD), X-ray fluorescence (FRX), scanning electron microscopy (SEM) and EDS. Tests of resistance to compression of the traces in the hardened state were also carried out and the rheological test of the geopolymer was carried out at the start of the reaction in the fresh state. For Davidovits ratios in the range of 2.5 to 3.23, the best geopolymers with compressive strength were obtained reaching 25 MPa in 24 hours of cure. For 60 days of cure at room temperature the geopolymers reached a resistance of 45, 36 MPa. The research carried out through the characterization analysis of the samples and the mechanical and rheological tests were presented in a satisfactory way and demonstrated that the residues of fly ash and metakaolin, when activated with sodium silicate and sodium hydroxide, are an alternative for the possible application of Geopolymer materials in construction.
Acesso aberto (Open Access)
Avaliação da formação zeolítica em sínteses com diferentes proporções de Si/Al via processo hidrotermal a partir de caulim durp (flint)
(Universidade Federal do Pará, 2023-02-23) FERREIRA, Aline Lopes; PINHEIRO, Alice dos Prazeres; http://lattes.cnpq.br/6671972168040423; MACÊDO, Emanuel Negrão; http://lattes.cnpq.br/8718370108324505
The zeolite synthesis is composed of several reactional factors, in which changing a condition can significantly modify the intensity trend of the zeolite crystals or even the type of zeolite formed. In this context, this work aims to explore the change in the Si/Al ratio in different time periods and analyze the formed product. Initially, the characterization of hard kaolin was carried out through FRX, DRX, MEV, TG, DTG and DSC analyses. Subsequently, the hard kaolin was calcined at 650 °C for 2 hours, with the aim of transforming the starting material into metakaolinite, facilitating the restructuring into zeolite in the reaction medium of the dynamic hydrothermal process. Altogether, 7 hydrothermal syntheses with different Si/Al ratios were carried out, each lasting 6 hours. In each synthesis, aliquots were removed every half hour and filtered, the liquid of which was used to carry out the titration, while the particulate material from the period of 1, 2, 4 and 6 hours was applied for verification in the X-Ray Diffractogram (DRX) and MEV. In all products, the crystalline phases referring to zeolite A, sodalite and in some points of faujasite and cancrinite were observed. In view of the data obtained, it was verified that all the compositions used had satisfactory results with zeolite formation from 1 hour of synthesis, that is, a short period of time. Furthermore, it was possible to verify in a visible way, through the intensity of the peaks and appearance or disappearance of zeolite types, the interference of time and the proportion of Si/Al in the medium. In addition to the XRD, the dendrogram analysis was used in order to identify clusters, that is, which products had similar characteristics, being able to analyze intervals of better formation. The MEV was carried out with the 1-hour material, verifying the characteristic morphology of zeolite A and sodalite, mainly in the proportions of Si/Al=1 and 1,5. The concentration of NaOH in the medium, verified by titration, showed little consumption of this reagent throughout the synthesis. However, it was concluded that the reaction conditions applied to the hard kaolin showed the capacity to form zeolites, allowing the verification of the formation.
Acesso aberto (Open Access)
Decomposição catalítica do glicerol em fase vapor usando a perovskita cecuxni1-xo3 (x=0;0.25) como precursor catalítico
(Universidade Federal do Pará, 2017-03-09) ESTRADA, Marcial Antonio Fuentes; FRANÇA, Luiz Ferreira de; http://lattes.cnpq.br/6545345391702172; RIBEIRO, Nielson Fernando da Paixão; http://lattes.cnpq.br/0755443458423442
The utilization of the fuels fossils like main source of energy has carried to the generation of countless environmental and economic problems, creating the need of diversification of the energetic matrix. In Brazil, country with vast territorial extension and agroindustry very established stands out the production of biofuels, such as: ethanol and biodiesel. Particularly, the production of biodiesel with the increasing governmental incentives exponentially has its production increased to each year placing Brazil in prominence in the worldwide scene of biofuels. In the process of transesterification of vegetal oils with a primary alcohol, beyond biodiesel, the rude glycerin in a ratio of 10% is generated 11% in volume. The bio refining of the deriving glycerin of the manufacture of biodiesel, becomes the production of biodiesel economically more viable, leading to the formation of products with raised aggregate values. For this reason, the present work has as main objective the valuation of the chain of production of biodiesel for the transformation of glycerol to the products of bigger value added through reaction catalytic decomposition of glycerol using perovskitas of the CeNi1-xCuxO3 type (x=0 and 0,25) as you will catalyze. The gotten results had shown that the use of high temperature (500 °C) favors the gas production of synthesis with approach relation H2/CO of 1, this occur for the strong craqueamento of the molecule of glycerol, At 410 ° C and inert reaction atmosphere, hydroxyacetone (acetol) was the major product exhibiting selectivity in the range of 22-28% depending on the catalyst used. The effect of the addition of hydrogen on the reaction load was investigated and its insertion promoted the hydrogenation of the hydroxyacetone, leading to an increase in selectivity for 1,2-propanediol whose selectivity varied in the range of 4-9% depending on the catalyst.
Acesso aberto (Open Access)
Determinação de propriedades termofísicas e estudo do equilíbrio líquido-líquido de sistemas envolvendo líquidos iônicos próticos
(Universidade Federal do Pará, 2017-03-24) GOMES, Rossimar dos Santos; SILVA, Silvana Mattedi e; http://lattes.cnpq.br/8741124364246075; SANTOS, Geormenny Rocha dos; http://lattes.cnpq.br/0844662601945669
This work consisted of the synthesis of protic ionic liquids (Ethyl 2-hydroxyethylammonium propionate [E2HEAP][PR], Diethylammonium propionate, [DEA][PR] and Butylammonium propionate, [BA][PR] and determination of density and viscosity of protic ionic liquids [DEA] [PR] and [BA] [PR] pure and the binary systems formed by these ionic liquids + water at different temperatures and atmospheric pressure. The density data were determined using a digital densimeter and viscosity by the viscometer, both of Anton Paar, the experimental results were used to obtain excess molar volume (𝑉𝑚𝐸), apparent molar volume (𝑉∅,1), viscosity deviation (Δη) and excess Gibbs free energy (ΔGE), being the results correlated with the Redlich-Kister or Redlich-Meyer equation. The results were compared and discussed based on the molecular interactions between the studied componentes. It was also made the study of liquid-liquid equilibrium data (LLE) for systems, involving 1-butanol + water + protic ionic liquids: [E2HEA][PR] or [DEA][PR] or [BA][PR] K and atmospheric pressure, being the systems quantified by the gravimetric method. The quality of the equilibrium data was verified by the semi-empirical methods of Othmer-Tobias and Hand. From the obtained equilibrium data, the values of the distribution coefficient found indicated the hydrophilic behavior of the LIs studied. Data liquid–liquid equilibrium was correlated by the NRTL and UNIQUAC thermodynamic models, which was observed that the NRTL model correlated in a more satisfactory way the results presenting global deviation of 1,56% for NRTL and 1,78% for UNIQUAC.
Acesso aberto (Open Access)
Dinâmica molecular de armazenamento de H2 em nanotubos de carbono sob ação de campo elétrico externo
(Universidade Federal do Pará, 2016-01-27) AIRES, Júlio Cesar Nunes; CHAVES NETO, Antônio Maia de Jesus; http://lattes.cnpq.br/3507474637884699; https://orcid.org/0000-0002-9730-3512
Several thermodynamic properties were analyzed through computer simulations systems, in which we used a carbon nanotube a gas molecule (H2), the very low initial temperature of 10-3K order. This H2 molecule was chosen because of its properties are of great application in different branches of study, the physical sciences, chemical and biological. The H2 molecule is individually relaxed inside and outside the nanotube during simulations. Each system was under the influence of a uniform electric field parallel to the carbon nanotube and the thermal effect on the initial temperature in the simulations generating the evanescent effect. Due to the electric field, the molecule rotates at a low temperature in orbit about the carbon nanotube while increasing the value of the electric field permitted the variation of the radius of the orbit atoms. The calculated amounts were the following: kinetic energy, potential energy, the total energy, temperature variation in situ, the molar entropy and the mean radius of the orbit atoms. The data suggest the action of the electric field is sufficient only to generate the evanescent attractive potential and this system can be used as a sensor selector atoms.
Acesso aberto (Open Access)
Espectroscopias RAMAN, IR, DOS, UV-Vis e dicroismo circular das toxinas (anatoxina-a, anatoxina-as, cilindrospermopsina, homoanatoxina-a e saxitoxina) das algas.
(Universidade Federal do Pará, 2024-02-02) LOBATO, Marinaldo Carvalho; COSTA, José Francisco da Silva; http://lattes.cnpq.br/9492719731740641; CHAVES NETO, Antônio Maia de Jesus; http://lattes.cnpq.br/3507474637884699
This thesis aims to understand Raman, IR, DOS, UV-Vis and Circular Dichroism spectroscopy of algal toxin molecules Anatoxin-a, Anatoxin-a(s), Cylindrospermopsin, Homoanatoxin-a and saxitoxin. The Gaussian 09W software was used for the theoretical calculations of energy minimization corresponding to the molecular mechanics method MM+ as well as the functional level B3lyp/6-311++G (d,p), used both in the optimization of the geometry and in the calculations of UV-Vis spectrometry, State Density and Circular Dichroism of non-solvent water molecules. The research results show relevant UV-Vis spectra, State Density, Circular Dichroism, Raman and Infrared in the elaboration of Tables that identify the modes of molecular vibrations of the aforementioned toxins, which lead to identifying the types of vibrations in each region contained in us specific wave compression intervals. Verify that each algal toxin presents a specific gap or that makes it possible to identify the one that presents the greatest reativity in relation to others (smallest gap) or greatest stability (largest gap). For the MEP (electrostatic potential map) it is possible to observe the region that presents the highest concentration of negative charges or that can be useful to identify regions of reaction between a toxin and a protein. The research was concluded considering an experimental comparison between the cylindrospermopsin toxin with graphical analyzes of two UV-Vis spectra that with a percentage of 0.5% of error, showing that based on B3lyp/6-311++G(d, p) selected was very significant for comparison between theoretical data in relation to experimental data.
Acesso aberto (Open Access)
O estudo da docagem e dinâmica molecular de potenciais fármacos: rodatina, scedapina C e cequinadolina A, utilizados no tratamento da SARS-COV-2
(Universidade Federal do Pará, 2022-05-06) LIMA, Antonio Sanderlei dos Santos; ALMEIDA, Ossalin de; http://lattes.cnpq.br/7040173036131516; HTTPS://ORCID.ORG/0000-0003-3895-0952; CHAVES NETO, Antônio Maia de Jesus; http://lattes.cnpq.br/3507474637884699; https://orcid.org/0000-0002-9730-3512
Due to the study of new drugs to combat the SARS-COV-2 virus, which is causing the COVID-19 pandemic. In this work, we address the use of three drugs (Rhodatin, Scedapin C and Scequinadoline A) as possible inhibitors of SARS-CoV-2, as they have several interactive properties, showing potential to be used in the treatment of COVID19 disease. Molecular docking provided information about the affinity energy which was -8.186, -9.617, -7.866, -7.601, -7.527 kcal/mol, for the best conformations with Scequinadoline A. Molecular couplings and affinity energy showed the residues of the site macrostructures, and analyzed the electrostatic potential map to predict some promising candidates for virus antagonists. Molecular dynamics techniques were used, where the targets were the external structures of the virus, but specifically the envelope protein, main protease, Spike glycoprotein. Using the GROMACS 2021.2 modules, the results showed that the ligands have characteristics of interaction over time. Molecular dynamics provided values between 1.5 and 4.5Å for the mean square deviation of atomic positions. Among the results obtained through molecular dynamics, it was noted that the hydrogen bonds, when compared to the calculation of the square root of the mean square deviation, underwent a change in the amount of hydrogen bonds in the bonding process, according to the proximity of the ligand used to filter out unrealistic poses in the snap, and also improved the accuracy of binding energy calculation. Analysis of molecular couplings showed that the S-gly active site residues strongly interacted with the three drugs. The reuse of these drugs in the fight against SARSCoV-2 may be candidates via virus antagonists, which if confirmed through experimental approaches, can contribute to the resolution of the global crisis of the COVID-19 pandemic.
Acesso aberto (Open Access)
Estudo da influência do óxido de cálcio nas reações de estado sólido na produção de agregado cerâmico a base de aluminossilicatos e resíduo do processo Bayer
(Universidade Federal do Pará, 2023-02-10) BRITO, Carlos Eduardo Costa; SOUSA, Jose Antonio da Silva; http://lattes.cnpq.br/6157348947425968; MACÊDO, Emanuel Negrão; http://lattes.cnpq.br/8718370108324505
The most important worry involving the generation of industrial waste is associated with the effects those materials can have on the environment and human health, considering that the dangerous waste produced by the industry requires particular care and attention, because if managed improperly, it can become a serious environmental threat. Therefore, this paper demonstrates the studies conducted to recycle the residue from the Bayer process, as a raw material in the production of synthetic aggregate, intended for civil construction. Furthermore, this paper has analyzed the influence of calcium oxide in the solid state reactions during sintering in the production of ceramic aggregates based on residue from bauxite processing because this oxide, besides being a melting material, also influences the formation of glass with lower viscosity, and may positively influence the mechanical strength of the material. For the conformation of the aggregates a composition based on bauxite residue and silica was adopted with and without the addition of calcium oxide. The pellets were produced in a rotating cylinder and sintered at temperatures of 1180, 1200 and 1250 °C with a burn time of 3 hours. For the characterization of the raw materials the techniques of X-ray Fluorescence (XRF), X-ray Diffraction (XRD), Differential Scanning Calorimetry (DSC) and Thermogravimetric Analysis (TG) were employed. For the characterization of the aggregate, scanning electron microscopy (SEM), XRD and DSC tests were performed on the formulations composed of bauxite residue and clay with and without the addition of calcium oxide. The physical and technological properties determined were: Water absorption, apparent porosity and apparent specific mass. The results of this paper indicate that bauxite residue can be used as a source of alternative raw material for the production of synthetic ceramic aggregate. The results obtained also prove that the use of calcium oxide directly influenced the solid state reactions, especially in the mullite formation reaction. Therefore, the production of synthetic aggregate with the addition of calcium oxide proved to be a promising destination for the Bayer process residue.
Acesso aberto (Open Access)
Estudo das alterações petrofísicas e mineralógicas em amostras de calcita e dolomita decorrentes da interação com água carbonatada e CO2 supercrítico
(Universidade Federal do Pará, 2023-05-29) SOUZA, Felipe Pereira de; LUCAS, Cláudio Regis dos Santos; http://lattes.cnpq.br/1695226159975283; HTTPS://ORCID.ORG/0000-0001-5443-462X; AUM, Pedro Tupã Pandava; http://lattes.cnpq.br/7515419219571335; https://orcid.org/0000-0002-2339-9865
CO2 capture, utilization, and storage techniques, known by the acronym CCUS (Carbon capture, utilization, and storage), have been studied as primary tools for achieving the decarbonization targets, stipulated to slow down the rise in temperature earth average. In this context, geological storage consists of injecting CO2 into the rock formation, so that it is trapped in saline aquifers, coal deposits or oil reservoirs. CO2 injection is already carried out, for example, in the Brazilian pre-salt fields, where the oil produced has a high concentration of CO2 in its composition. It is expected that other geological structures can be used for geological carbon storage. However, the geological sites must be carefully selected, one of the key points being the geochemical stability due to the contact of CO2 with the rock formation. Thus, this project aimed to study the process of interaction of CO2 with formations of carbonate rocks, to increase the fundamental knowledge regarding the processes of rock-fluid interaction in the geological storage of CO2. The methodology included the analysis of the petrophysical properties of commercial carbonate rocks (Indiana Limestone and Silurian Dolomite) and of the dolomitic carbonate sample from the Itaituba Formation, before and after exposure to CO2 in the form of carbonated water and in the supercritical form. We also used X-ray microtomography to study the porous structure of samples at different scales. The results showed that the Indiana rock samples present distributed porosity, being essentially formed by structures predominantly composed of pallets, skeletal grains, ooids and shell fragments. The samples of Silurian Dolomite presented a structure formed by less pores, however larger and more concentrated. The rock samples from the Itaituba formation showed very low porosity and permeability. The petrophysical properties evolved after contact with CO2. Rock-fluid interaction studies will show changes in rock matrices resulting from the dissolution/or expansion process. The microtomography technique of x-ray was used in the imaging of the samples to visualize the change in the morphology of the rocks, the technique allowed the comparison of before and after CO2 attack. The DRX and FRX analyzes showed positive results regarding the mineral composition of the samples used. The results of this work will contribute to the reduction of uncertainties related to the processes and mechanisms of the geological storage of CO2.
Acesso aberto (Open Access)
Estudo de quantificação de compostos fenólicos, avaliação de atividades antioxidantes e modelagem molecular da croton pullei var. Glabrior lanj
(Universidade Federal do Pará, 2021-04-16) SOUZA, Alexandre Augusto Moraes de; COSTA, Renato Araújo da; http://lattes.cnpq.br/6578338979054891; BRASIL, Davi do Socorro Barros; http://lattes.cnpq.br/0931007460545219
The study aimed to evaluate, from extracts, the yield (on a dry basis), quantify the total polyphenols, evaluate the antioxidant activity, perform a theoretical NMR research of the julocrotine, crotonimide A and crotonimide B structures, from Croton pullei VAR. glabrior LANJ. and evaluate these molecules in molecular docking against the enzymes Candida albicans (PDB ID: 1AI9), Staphylococcus aureus (PDB ID: 1DIM) and Salmonella thyphimurium (PDB ID: 4URM). A conventional extraction was performed using a stainless-steel extractor and three-factor planning (temperature, particle size and solid/liquid ratio) and three Box-Behnken levels, to determine which variables were influential in the responses. The quantification of total polyphenols was performed according to the Folin-Ciocalteu methodology. For the antioxidant analysis, the IC50 method was applied. And the theoretical NMR study was carried out via DFT, where the computational methods DFT/B3LYP/cc-pvDZ and DFT/B3LYP/6-31 G* were applied to obtain the chemical displacements (δH and δC), to compare to the experimental ones and thus provide which computational method is the most efficient. Yields vary between 5.57 and 10.61. In the quantification of total polyphenols, there was a variation between 101.33 and 308.84 mg EAG/g. The minimum and maximum antioxidant values were 94.74% and 98.97%. In general, the DFT/B3LYP/cc-pvDZ methodology was more efficient compared to the analyzed structures. The molecules showed hydrogen bonds with residues Lys 57 (A), Arg 56 (A), Cys37, Gly38, Asp62, Gly193, Tyr342, Gly56, Arg37, Tyr128, Arg56, Thr58 (A), Gly114 (A) and Thr 127.
Acesso aberto (Open Access)
Estudo do efeito da saturação de óleo na acidificação de carbonatos
(Universidade Federal do Pará, 2023-02-27) NEYRA, Jair Rodrigues; LUCAS, Cláudio Regis dos Santos; http://lattes.cnpq.br/1695226159975283; HTTPS://ORCID.ORG/0000-0001-5443-462X; AUM, Pedro Tupã Pandava; http://lattes.cnpq.br/7515419219571335; https://orcid.org/0000-0002-2339-9865
Carbonate acidizing is a well stimulation technique used to increase oil production. This technique aims to inject acid into the formation below the fracture pressure, creating paths of high conductivity resulting from the dissolution of the rock by the acid. In the laboratory, most experiments are performed on rock samples saturated with water, due to the assumption that there is only water in the formation, after preflush and previous drilling and completion operations. However, different saturation conditions can occur in the formation due to its petrophysical characteristics and history of operations. One scenario is oil saturation in the porous medium. This work proposes to carry out physical experiments and evaluate the influence of oil saturation on the acidizing of carbonates. Reactive flow experiments were carried out using acid systems, with HCl 0.5M and HCl 15%, in rocks saturated with ultra pure water and liquid paraffin. The carbonate rock samples are from the Indiana Limestone outcrop with 3 in length and 1.5 in diameter. For oil saturation, a high flow rate of 20 mL/min was used for the two acid systems at room temperature (25°C); and with HCl 15%, the study was deepened with a temperature of 45°C at flow rates of 1 and 20 mL/min. The x-ray microtomography technique was used to image the samples to visualize the wormhole morphology. Through it, the influence of oil on the structure of the wormhole and the value of PVBt was compared, highlighting the impact of oil for each acid concentration. The PVBt curve of HCl 0.5M has values above those presented using HCl 15%, in samples saturated with water. This effect is due to the lower concentration promoting a lower dissolution power of carbonates. The analysis of the wormhole area and the porosity distribution after acidizing show that the oil influenced an efficient propagation of the wormhole and lower consumption of acid. PVBt values are lower when the sample is saturated with oil in all scenarios. The use of HCl 15% in the sample saturated with oil and at a temperature of 45°C. In this scenario, the value reduces by about 54% when using HCl 15% at 20 mL/min.
Acesso aberto (Open Access)
Estudo do processo de pirólise de caroços de açaí Í (Euterpe oleracea Mart.) em escala piloto para produção de biocombustíveis
(Universidade Federal do Pará, 2022-06-27) BAIA, Ana Cláudia Fonseca; SANTOS, Marcelo Costa; http://lattes.cnpq.br/8380189608965320; HTTPS://ORCID.ORG/0000-0002-2352-2050; CARVALHO JÚNIOR, Raul Nunes de; http://lattes.cnpq.br/5544305606838748; https://orcid.org/0000-0002-4433-6580
The objective of this work was to study the process of bio-oil production through the pyrolysis of raw acai kernel on a pilot scale, focusing on the yield of products obtained at temperatures of 350°C, 400°C and 450°C at 1 atm. In addition to studying the results obtained via gas chromatography coupled to mass spectrometry (GC-MS) of the bio-oils produced. For the experimental procedure, the raw material used was the açaí pits, a residue obtained after the process of pulping the fruit. This material went through stages of drying, comminution and sieving to remove unwanted residues for the process. This material was characterized by determining the moisture content, volatile content, ash content, fixed carbon content and higher calorific value. After the characterization process, the lumps were submitted to the pyrolysis process and, after the due separation processes, the bio-oil obtained was submitted to tests to determine its acidity index, absolute density, refractive index, and dynamic viscosity. After this step the bio-oil was subjected to analysis in a gas chromatograph coupled to a mass spectrometer. The moisture content found in the açaí seeds was approximately 40% and the yield of the pre-treatment step was 46.84%. In the physical characterization of the seeds the results found were within the existing literature showing interesting properties for use in the pyrolysis process. With the increase in temperature there was a favorable production of bio-oil and biogas, while for the biochar there was a decrease in its mass produced. The physicalchemical analyses applied to the Bio-Oil produced were within the values that are available in the literature for this same type of material, however, it is still outside the standards that the National Petroleum Agency establishes for green diesel. The increase in temperature reduced the acidity of the bio-oil and increased its viscosity and density. With this, there was a reduction 92.87 (Exp.1) to 70.26 (mg of NaOH/g of sample) (Exp.3) and the lowest kinematic viscosity obtained of 77.62 mm²/s for the pyrolysis process with the temperature set up to 350°C. The chromatographic analysis showed that the compound with the highest percentage of peak area was phenol, where the average retention time was 8,466 min-1 independent of the programmed temperature. Exp.2 had the highest yield in terms of aromatic hydrocarbons and the lowest yield for phenols, showing that there is no linear behavior with temperature change.
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)
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 da temperatura de calcinação na redução da hematita e na liberação do titânio na lama vermelha (resíduo do processo bayer)
(Universidade Federal do Pará, 2016-12-26) VIEGAS, Bruno Marques; MAGALHÃES, Edilson Marques; CV: http://lattes.cnpq.br/1570353513360972; MACÊDO, Emanuel Negrão; http://lattes.cnpq.br/8718370108324505
In this work a technological route was proposed aiming at the reduction of hematite to magnetite and the release of titanium present in red mud from Hydro Alunorte. The fluorescence and x ray diffraction analysis showed that the red mud presents in their composition approximately 5% of titanium oxide as anatase and 28% of iron oxide in the forms of hematite and goethite. Therefore, the proposed route will enable the obtainment of a material with magnetic characteristics which can be used as source of titanium after extraction of iron compounds in magnetic form. So, the reduction of the hematite to the magnetite was carried out by thermal treatment in a reducing atmosphere. To accomplish this, mixtures were made in different concentrations of red mud and charcoal. These mixtures were calcined at temperatures of 500, 600 and 1000 ° C for two hours. Then, X ray diffraction analysis were performed, which showed that the hematite was reduced to magnetite in all experimental conditions and, for the mixtures calcined at 1000 ° C, besides the formation of the magnetite, there was also the formation of maghemite. Through analysis of Raman spectroscopy and scanning electron microscopy, it was verified that for calcination temperatures of 500 to 600° C titanium remained in the free form of anatase, but for the calcination carried out at 1000° C this passed to the combined form with iron (ilmenite). The technological route allowed the formation of magnetite from the red mud, which can be extracted with the use of a magnetic separator.