Engenharia Química

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http://repositorio.ufes.br/handle/10/17472

Programa de Pós-Graduação em Engenharia Química

Centro: CCAE
Telefone: (28) 3552 8719
URL do programa: http://www.engenhariaquimica.alegre.ufes.br/pos-graduacao/PPEQ

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Agora exibindo 1 - 20 de 65

Adsorção de amina aromática em negro de fumo
(Universidade Federal do Espírito Santo, 2021-08-27) Rodrigues, Layza; Profeti, Demetrius; https://orcid.org/0000000345653331; http://lattes.cnpq.br/5030262115789096; https://orcid.org/0000-0002-2999-5377; http://lattes.cnpq.br/8836000296144436; Costa, Ariany Binda Silva; https://orcid.org/0000-0001-7320-3317; http://lattes.cnpq.br/9518055204202962; Passos, Renato Ribeiro; https://orcid.org/000000017730748X; http://lattes.cnpq.br/3882320619443256
Aromatic amines, such as ortho tolidine (o-tolidine), are used as raw material for dye synthesis and are also used as reagent for analyzing residual chlorine level within treated drinking water. Due to the high toxicity, these compounds require proper disposal and treatment of wastes to avoid the contamination of water resources. Adsorption is an efficient, low-cost, and simple design technique in the treatment of liquid waste, compared to other conventional methods used in the removal of contaminants. In this context, the study of adsorbent materials has been developed with an emphasis on low-cost and highly available materials. Carbon black is considered a versatile recycled material with great applicability, but despite the suitable characteristics, its use as adsorbent material is still scarce. Therefore, in this work, the removal of aromatic amine (otolidine) from aqueous solutions using carbon black (Vulcan XC 72R) as adsorbent material was studied. The Vulcan XC 72R was characterized by Raman spectroscopy, scanning electron microscopy (SEM), thermogravimetric analysis (TGA), energy dispersive spectroscopy (EDS) and hydrogen ion potential corresponding to the zero point of charge (pHzpc). Batch adsorption experiments were performed for evaluating the effects of contact time, pH and concentration on adsorption. Moreover, the study of the adsorption equilibrium and kinetics were carried out. According to the Raman spectrum, Vulcan XC 72R showed two characteristic bands of amorphous and graphitic phase, D and G respectively. Furthermore, the intensity ratio of the two bands showed that the amorphous phase prevails. The SEM images showed a rough surface with small agglomerates uniformly distributed. TGA showed a rapid thermal decomposition, which is assigned the presence of carbon and oxygen. The elemental analysis performed by EDS confirms the TGA results. The pHPZC was found as 6.74. The Avrami kinetic model best fit the process. The Webber and Morris model indicated that the adsorption mechanism is controlled by the boundary layer effect in addition to intraparticle diffusion. The Temkim isotherm best fitted the equilibrium results and a maximum removal capacity around 64 mg g-1 at 25°C. Temperature and pH did not significantly influence the o-tolidine adsorption mechanism. According to the results, the carbon black Vulcan XC-72 R showed high potential to be used as an adsorbent material for decontamination of effluents containing the aromatic amine o-tolidine.
ADSORÇÃO DE CORANTE INDUSTRIAL REATIVO PRETO 5 UTILIZANDO CARVÃO VULCAN XC-72
(Universidade Federal do Espírito Santo, 2020-10-30) Mota, Marcos Vinicius de Carvalho; Profeti, Demetrius; https://orcid.org/0000000345653331; http://lattes.cnpq.br/5030262115789096; https://orcid.org/; http://lattes.cnpq.br/; Costa, Ariany Binda Silva; https://orcid.org/; http://lattes.cnpq.br/9518055204202962; Passos, Renato Ribeiro; https://orcid.org/000000017730748X; http://lattes.cnpq.br/3882320619443256
Nowadays, problems causedbywater resources contaminationhave been more impactful. The textile industries effluent has a large concentration of dyes and pigments, whose change color, turbidity, dissolved oxygen, among other parameters unbalance the local e
Adsorção de sulfato por compósito de hidróxido duplo lamelar do tipo Mg6Al2(CO3)(OH)16.4H2O e quitosana
(Universidade Federal do Espírito Santo, 2022-08-18) Pessanha, Maria Luiza Gomes Soares; Guimarães, Damaris; https://orcid.org/0000000249323252; http://lattes.cnpq.br/6576377621734943; Altoe, Mario Alberto Simonato; http://lattes.cnpq.br/8481776828705621; Profeti, Demetrius; https://orcid.org/0000000345653331; http://lattes.cnpq.br/5030262115789096
The sulfate is a common ion present in several wastewater industrial segments and domestic wastewater. The high concentration of sulfate ion could cause several types of damage, like laxative effect on humans and animals, and is related to incrustation and corrosion of industrial pipes. For the treatment of these effluents, the adsorption technique stands out for the variety of adsorbents. In this work, the SO4 2- adsorption process by the LDH-Mg-Al-CO3 and chitosan composite was carried out. The chitosan was synthesized from shrimp residues from the region, and the composite was synthesized by the co-precipitation method, common in the LDH synthesis. The DD% was determinated for chitosan, obtaining the value of 54,47% which confirms that the material obtained from the deacetylation of chitin can be considered chitosan. The characterization of adsorbents was carried out through the XDR, SEM-EDS and FTIR techniques, showing that the material has characteristic peaks and morphological aspects of LDH-Mg-Al-CO3 and chitosan before and after adsorption, indicating there was no change in the structure of the material. The kinetic test showed the SO4 2- loading by the LDH-Mg-Al-CO3 and chitosan composite was 234,15 mg g-1, and the equilibrium time was reached in 180 minutes. Applying kinetic models to the data, pseudo-first order (R² = 0,93) and pseudo-second order (R² = 0,91) resulted in similar values, and it was not possible to conclude which of them best fitted the kinetic data. With the isotherm study, it was observed the Redlich-Peterson model (R²= 0,96, β=0,84) was the best model adjusted to data, assuming behavior of the Langmuir isotherm with monolayer adsorption, because the β parameter is closer to 1. In view of the results obtained throughout the study, it was possible to observe that there was a synergy between LDH-Mg-Al-CO3 and chitosan in the composite, which resulted in better loading results of SO4 2- adsorption, in relation to the precursor adsorbents.
Análise da cinética de decomposição térmica da casca de urucum (bixa orellana l.)
(Universidade Federal do Espírito Santo, 2024-05-28) Breciani, João Guilherme Fraga; Sousa, Robson Costa de; Costa, Ariany Binda Silva; https://orcid.org/0000-0001-7320-3317; https://orcid.org/; http://lattes.cnpq.br/; Carvalho, Romero Florentino de; https://orcid.org/; http://lattes.cnpq.br/; Alves, Rejane Costa; https://orcid.org/; http://lattes.cnpq.br/; Perazzini, Maisa Tonon Bitti
This study aims to investigate the drying kinetics and thermal decomposition of annatto husks (Bixa orellana L.) in a nitrogen atmosphere. The analysis was performed through physical-chemical, thermal, and thermodynamic characterizations of the residue. Based the data obtained from the physico-chemical characterization, the residue's energy potential was verified, showing a low ash content and high calorific value. The thermal characterization was carried out using thermogravimetric analysis of the residues at different heating rates, which allowed for the determination of the material's peak, ignition, and burnout temperatures during the pyrolysis process. From this data, a drying kinetics study was performed, where the Page model provided the best fit to the experimental data. Additionally, the thermal decomposition kinetics of the material was studied using global and multicomponent models. Among the global models, Friedman, FWO, KAS, and Vyazovkin models were analyzed, but none were suitable for experimental representation. For the multicomponent models, consecutive reactions and independent parallel reactions were analyzed, both showing excellent fits, with TG deviations below 2.6% for all heating rates analyzed. Finally, in the thermodynamic characterization, the values of enthalpy, Gibbs free energy, and entropy indicate that the thermal decomposition of annatto husks in a nitrogen atmosphere is an endothermic and non-spontaneous process.
Análise da dispersão de poluentes em rios via aproximação Bayesiana
(Universidade Federal do Espírito Santo, 2019-02-13) Faria, Ruan de Rezende; Silva, Wellington Betencurte da; Guidolini, Icaro Pianca; Dutra, Julio Cesar Sampaio; Guidolini, Icaro Pianca; Costa, Ariany Binda Silva; Costa, José Mir Justino da
Study of the dispersion of pollutants in rivers is related to the analysis of the load of conservative pollutants released instantaneously (diffuse sources of pollution) or of continuous way (point sources) in a given river. These problems were addressed in this master's dissertation by means of experimental data with conservative tracer injected in pulse and continuously. The objective was to identify tracer characteristics (i.e., magnitude, spatial distribution and duration of activity). The approach to the dynamics of these problems was carried out by means of approximation of inverse problems, being computed by the Simulated Annealing (SA) method and the assimilation of data based on the Bayesian methods of Particle Filtering (PF). The SA method allowed obtaining satisfactory results in the representation of the dynamics of the system off-line. These results were statistically evaluated by using 120 algorithm repetitions and different levels of uncertainty. However, one important limitation was the computational time to approximate on-line. For this reason, the PF (particle filtering) has been used to quantify the uncertainties in different conditions of priori distribution and number of particles, observing sequentially the performance of the SIR and SIR particle filter with Kernel smoothing in relation to the Root Mean Square (RMS), coefficient of determination (R2 ), autocorrelation coefficient of the residue (SC) and minimum resampling coefficient (REAmin). Better results were obtained through the Kernel smoothing technique, responsible for reducing sample depletion of the SIR particle filter. Therefore, the use of the SIR filter with the Kernel smoothing has been confirmed as an alternative for possible applications of river pollution control, virtual inference and alarm.
APLICAÇÃO DE CASCAS DE EUCALIPTO NA PRODUÇÃO DE TANASES POR FERMENTAÇÃO EM ESTADO SÓLIDO
(Universidade Federal do Espírito Santo, 2020-03-17) Pirola, Ana Caroliny Ferreira; Pinheiro, Iara Reboucas; https://orcid.org/; http://lattes.cnpq.br/8986864745281356; https://orcid.org/0000000210561448; http://lattes.cnpq.br/; Paes, Juarez Benigno; https://orcid.org/0000000347764246; http://lattes.cnpq.br/3454401627877927; Guimaraes, Damaris; https://orcid.org/0000000249323252; http://lattes.cnpq.br/6576377621734943
Tannase is an industrially important enzyme and has several applications in the food, animal feed, beverage, pharmaceutical and chemical industries. It can be obtained from animal, vegetable and microbial sources, being the microbiological medium main sou
Aplicação de meta-heurísticas para otimização de redes de trocadores de calor
(Universidade Federal do Espírito Santo, 2019-02-22) Oliveira, Gustavo dos Santos; Poubel, Willian Melo; Mauri, Geraldo Regis; Sousa, Robson Costa de; Mendes, Helder de Amorim
This work proposes the application of two metaheuristics to optimize a heat exchangers network. The network consists of combining heat exchangers among different stream increasing the overall value. In this work, two different cases were considered for a network in which the non-equivalent division of current and mixture between stages is allowed or not. Despite the existence of several metaheuristics, some considered classical have not been widely applied for this type of problem. Thus, in this work we propose a Simulated Annealing algorithm and a GRASP algorithm to optimize the two cases of a heat exchangers network. Both algorithms were able to obtain good solutions for the two cases within small computational time. For the first case, a direct comparison with a work presented in the literature was performed, and solutions similar to the best known so far were obtained in a considerably smaller computational time. For the second case, there was no direct comparison with the literature due to the lack of works that deal with the network with the same characteristics. However, the obtained solutions demonstrated the possibility of a considerable gain when the division and mixing of currents in the network is applied. The values of the best solutions obtained are presented for further comparisons.
Aplicação de um esquema de simulação e monitoramento via filtro de partículas na produção de etileno a partir do etanol.
(Universidade Federal do Espírito Santo, 2017-02-13) Salardani, Luciana Souza Ferreira; Silva, Wellington Betencurte da; Dutra, Júlio Cesar Sampaio; Vieira, Fabrício Thiengo; Costa, José Mir Justino da
The present work discusses about the mathematical modeling, numerical simulation and the monitoring problem based on particle filter using single-point temperature measurements for the green ethylene production process from the catalytic dehydration of ethanol. With the scarcity of natural resources, the use of sustainable sources such as biomass instead of petroleum derivatives has been encouraged. For example, the ethylene required by the thermoplastics industry can be obtained from the catalytic dehydration of ethanol, which then generates green ethylene or bioethylene. Most of the published works about this process refer only to the synthesis of catalysts, mechanism and kinetics and no one were found considering the Bayesian estimation tool. Thus, the main contribution of this work is the proposal of an estimation scheme composed of a direct problem for the process simulation and generation of pseudo-measures, and by an inverse problem for the estimation of the interest variables by means of the particles filter. The numerical simulations allowed to understand the process and to locate the best position for the temperature sensor in the reactor. From the measurements of temperature, the proposed inferential tool estimates the latency variables and the unmeasured perturbations using the Sampling Importance Re-sampling Filter (SIR) algorithm. The filter performance is investigated according to the number of particles and the total error reduction (TER) criterion. It can be observed that the results of the numerical simulation are in agreement with the literature and that the proposed monitoring scheme was able to satisfactorily estimate the process variables and the disturbance.
Aplicação de uma Estratégia de Controle Preditivo não linear a um Reator de Polimerização com Múltiplos Catalisadores.
(Universidade Federal do Espírito Santo, 2021-05-25) Silva, Luiz Felipe Neiva da; Dutra, Julio Cesar Sampaio; https://orcid.org/0000-0001-6784-4150; http://lattes.cnpq.br/5331990513570911; https://orcid.org/0000-0001-6882-4039; http://lattes.cnpq.br/5212012437726963; Carreira, Lilian Gasparelli; https://orcid.org/0000-0003-2415-6299; http://lattes.cnpq.br/8151437321864971; Costa, Ariany Binda Silva; https://orcid.org/0000-0001-7320-3317; http://lattes.cnpq.br/9518055204202962
Polymeric materials production is one of the most important areas in industrial activities, due to its great economic and social impact. Polypropylene, obtained by forming long chains of propylene monomer, is currently the 2nd most marketed plastic resin, representing almost two thirds of global propylene consumption, with several applications in engineering and daily life. Such economic interest forces the search for effective productivity gains while reducing costs is inherent to productive activities. Several polymerization methods, combined with production technologies and mixing of different catalysts, are used to manufacture different products. This has led to the design of multi-purpose equipment or processes that must be able to produce materials with different types of quality. In real polymerization plants, frequent changes in control objectives, nonlinear dynamics of the process, input of disturbances and the occurrence of faults pose serious operational challenges. Therefore, without a strategic and efficient control and monitoring system, multipurpose operation would not be possible. In this context, this work proposes a predictive control scheme based on a non-linear model (NMPC), which is applied to the simulation of a propylene multi-purpose polymerization reactor with the use of a mixture of 3 different catalysts. This scheme comprises a layer of supervisory control (NMPC) referring to the specification of the quality of the polymer and another layer for regulatory control (PID) to guarantee process stability. The results showed the NMPC - PID control scheme allowed improvements in the process control in all catalyst mixtures, providing good performance and consistency in the control, in addition to avoiding certain problems in the industrial scope, which highlights its potential for practical application.
Aplicação do método da integral dupla em um problema de solidificação em geometria esférica
(Universidade Federal do Espírito Santo, 2021-11-04) Canzian, Estefânia Pintor; Barañano, Audrei Giménez; https://orcid.org/0000000201745202; http://lattes.cnpq.br/6155024776819193; https://orcid.org/0000-0003-4118-0119; http://lattes.cnpq.br/1773575397759900; Barbosa, Mariana Ricken; https://orcid.org/0000-0003-0802-4309; http://lattes.cnpq.br/8760861693553546; Costa, Ariany Binda Silva; https://orcid.org/0000-0001-7320-3317; http://lattes.cnpq.br/9518055204202962; Mady, Carlos Eduardo Keutenedjian; https://orcid.org/0000-0001-8097-0629; http://lattes.cnpq.br/8200282913635713; Santiago, Fabio; https://orcid.org/0000-0003-1854-1983; http://lattes.cnpq.br/9172880946351461
The solution of heat transfer problems involving solidification is important in several applications in engineering, such as: growth of pure crystals, purification of several materials, more efficient thermal storage systems, development of improved methods for the solidification of metals and alloys in casting processes, among other applications. In this context, this study aims to apply the double integral method to obtain approximate solutions of spherical solidification problems and to obtain a refinement of the simple integral method solution available in the literature. Thus, both methods were applied to the differential equation that models the solidification phenomenon in spherical geometry using a linear quadratic temperature profile. Initially, the results obtained by the methods with the linear profile were compared with the solution proposed in the literature, and, in all cases analyzed, the double integral method obtained superiority over the simple integral method for the calculating of the solidification time. When comparing the results obtained from the integral methods with numerical data available in the literature, the double integral method with quadratic profile provided superior results compared to the simple integral method with the quadratic profile available in the literature. Furthermore, the double integral method using the quadratic profile presented better performance for the calculation of the solidification time in all analyzed cases, when evaluated with the experimental data present in the literature. Showing that this method is able to provide a better approach to the solution of the physical problem under study.
Aproveitamento de resíduos da biomassa da laranjeira (Citrus sinensis) para geração de bioenergia
(Universidade Federal do Espírito Santo, 2023-03-03) Dias, Luciano da Costa; Oliveira, Michel Picanco; https://orcid.org/0000000192410194; http://lattes.cnpq.br/6383844066460475; http://lattes.cnpq.br/8081489446643728; Dias, Josinaldo de Oliveira; https://orcid.org/0000-0001-6865-851X; http://lattes.cnpq.br/1030155171981790; Protásio, Thiago de Paula; https://orcid.org/0000-0002-5560-8350; http://lattes.cnpq.br/3847639263484797
In the culture of orange (Citrus sinensis), the focus is the production of the fruit, which, when in decline in connection with renewal of the orchards, results in the generation of waste, especially wood, which is not in the roll of biomasses for use in bioenergy. In this sense, the objective was to chemically and energetically analyze the orange wood, produce compacted solid biofuels (briquettes) and verify the quality produced briquettes. In the chemical and energetic characterization were used three compositions, 100% trunk (100T), 90% trunk + 10% bark (90T10B) and 100% bark (100B). The first two compositions were used in the production of briquettes with pressures of 10 and 12 MPa, totaling four types of briquettes named as 100T10P, 100T12P, 90T10B10P and 90T10B12P. The compaction temperature was 90ºC. The 100T composition presented lower extractives value (6.66%), higher lignin and holocellulose content (24.01% and 72.19%) and higher useful calorific value (17.51 MJ.kg -1 ) and the composition 100B presented higher ash content (10.35%). In relation to briquettes produced, apparent density and density by densitometry of xrays was higher in the type of briquette 90T10B12P, 1218 and 1194 kg.m-3 respectively. The briquette 100T10P obtained greater volumetric retraction (3.83%) and the lowest moisture absorption occurred in the 90T10B12P. The briquette 100T12P obtained higher value in the compressive strength test (3.12 MPa), but lower combustion index (0.16). The densification between the pressures used in briquetting was evidenced in scanning electron microscopy (SEM). The orange wood presented chemical and energy composition similar to the biomass for energy purposes and the briquettes produced showed low moisture, mechanical strength and combustibility within the appropriate levels according to the literature.
Atividade nematicida do fungo Pleurotus ostreatus e de suas proteases
(Universidade Federal do Espírito Santo, 2015-06-08) Genier, Hugo Leonardo André; Pinheiro, Iara Rebouças; Barañano, Audrei Gimenez; Soares, Filippe Elias de Freitas
Avaliação da adsorção da etilenotioureia utilizando esmectita Cu(II) como adsorvente
(Universidade Federal do Espírito Santo, 2019-02-22) Bazzarella, Andréia Zacchi; Profeti, Demetrius; Profeti, Luciene Paula Roberto; Neves, Mirna Aparecida; Altoe, Mario Alberto Simonato
Caracterização da fibra da planta Agave angustifolia var. marginata para aplicação em compósitos de poliéster
(Universidade Federal do Espírito Santo, 2023-02-28) Silva, Roseméri Barbosa dos Santos da; Oliveira, Michel Picanco; https://orcid.org/0000000192410194; http://lattes.cnpq.br/6383844066460475; https://orcid.org/000900046432591X; http://lattes.cnpq.br/1686173233289342; Candido, Verônica Scarpini; https://orcid.org/0000-0002-3926-0403; http://lattes.cnpq.br/8274665115727809; Moulin, Jordão Cabral; https://orcid.org/0000-0002-5543-3853; http://lattes.cnpq.br/3577181658928552
The use of lignocellulosic fibers (natural fibers) has beenwidely investigated as a reinforcement material in polymeric composites because it presents characteristics of biodegradability, low cost, low density and mechanical properties relevant to the replacement of synthetic fibers. In the present study, lignocellulosic fibers of Agave angustifolia var. marginata (AAM) were characterized in order to evaluate their potential as a reinforcement material and their influence on unsaturated polyester matrix composites. Thus, X-ray diffractometry (DR-X) and Fourier transform (FT-IR) spectroscopy, thermogravimetry, diametral distribution, fiber traction test and scanning electron microscopy (SEM) were performed. The application of long fibers as reinforcement material in the unsaturated polyester matrix was evaluated for proportions of 10, 20 and 30% by weight in a guided way. The properties of the composites developed for the different fiber contents of A. angustifolia var. marginata (FAAM) were investigated in order to analyze the interactions between fiber and matrix, thermal stability, mechanical properties, SEM of the fracture surface and resistance to water absorption. It was found that the addition of FAAM in the polyester matrix provided significant improvements in the mechanical properties of traction and impact. It was observed that with the addition of 10%, 20% and 30% by weight of FAAM in the polyester matrix the average strength of the composites had an increase of 56%, 180% and 293%, respectively. The thermal stability and moisture resistance of the reinforced composites were lower compared to polyester. The scanning electron microscopy (SEM) analysis showed that there was a good adhesion between fiber and matrix, in which they acted as effective barriers preventing and diverting the cracks of the matrix, and as an effect increased the absorbed impact energy and the tensile strength of the composites. Thus, the results found in this study indicate that the natural fibers of AAM exhibit reinforcement characteristics for application in polymeric composites.
Caracterização de plasmas frios por espectroscopia óptica de emissão
(Universidade Federal do Espírito Santo, 2019-02-20) Alves, Douglas Pereira; Pinheiro, Christiano Jorge Gomes; Colistete Junior, Roberto; Sousa, Robson Costa de
Although little known outside and even within the academic community, plasma, considered the fourth state of matter, is the most abundant state in the known universe. Plasma is defined as an electrically neutral medium containing neutral species and electrically charged species, such as electrons, positive ions, and negative ions that exhibit collective behavior. Plasmas can be both naturally found and produced in the laboratory. Artificial plasmas can be generated in a wide range of pressure and temperature and have the most diverse applications. In particular, cold plasma at atmospheric pressure has been widely used in biomedical applications. Considering the potential of plasmas application, this work aimed at characterizing the cold plasma at atmospheric pressure produced by a Dielectric Barrier Discharge (DBD) reactor. Through optical emission spectroscopy (EOE), a noninvasive technique of characterization of plasmas, where what is measured is the electromagnetic radiation emitted by the medium, the main physical properties of the plasma were inferred. These are the electron density, the gas temperature and the electronic excitation temperature. In addition, a study was carried out on the macroscopic neutrality of plasma loading, Debye's length, plasma parameter and plasma frequency, which are necessary for the definition of plasma. These parameters were obtained from a high resolution monochromator for different values of power and frequency applied to the plasma generator device, obtaining quite satisfactory results and in agreement with the literature.
Caracterização e aplicação das fibras de Cyperus papyrus em compósito polimérico
(Universidade Federal do Espírito Santo, 2024-08-29) Nascimento, Mateus Urbano do; Oliveira, Michel Picanço ; https://orcid.org/0000-0001-9241-0194; http://lattes.cnpq.br/6383844066460475; https://orcid.org/0009-0008-3032-8134; http://lattes.cnpq.br/5290180524562317; Pereira, Artur Camposo ; https://orcid.org/0000-0002-5882-9781; http://lattes.cnpq.br/9933475136538529; Moulin, Jordão Cabral ; https://orcid.org/0000-0002-5543-3853; http://lattes.cnpq.br/3577181658928552
The growing environmental concern and the need for eco-efficient alternatives to structural materials have increased the demand for sustainable and innovative materials. In this regard, research and exploration of plant fibers for use in composites as a substitute for conventional forms have shown promise. In this context, this work aims to characterize and apply papyrus fibers (Cyperus papyrus) as a reinforcement element in a composite of epoxy resin with epoxidized soybean oil. The papyrus fibers were manually extracted from the plant and characterized in terms of their physical, chemical, thermal, morphological, and mechanical properties. Composites were produced from the fibers using an epoxy matrix incorporated with 20% epoxidized soybean oil, and three proportions of aligned fiber mass in the composites (10%, 20%, and 30%) were evaluated through chemical, thermal, and mechanical analyses. The fibers had an average diameter of 167.42 µm and a maximum tensile strength of 188.21 MPa. The crystallinity index of the fibers was 58.56%, and their thermal stability was 220°C. The best properties were achieved in the composites reinforced with 30% fiber, reflecting a mechanical improvement, with increases in tensile strength and modulus of elasticity of 133% and 630%, respectively, and thermal stability up to 262°C. However, the composites exhibited reduced deformation and toughness with the addition of fibers, indicating a more brittle nature. Thus, papyrus fibers demonstrated potential for use in composites and were effective in reinforcing the epoxy/epoxidized soybean oil matrix
Caracterização e secagem convectiva do bagaço da laranja (Citrus Sinensis L. Osbeck) como biomassa lignocelulósica visando o aproveitamento energético
(Universidade Federal do Espírito Santo, 2023-08-18) César, Mariana; Sousa, Robson Costa de; http://lattes.cnpq.br/7320586055142013; http://lattes.cnpq.br/1650399480372339; Perazzini, Maisa Tonon Bitti; Moulin, Jordao Cabral; http://lattes.cnpq.br/3577181658928552; Carvalho, Romero Florentino de
It is estimated that around 50% of the weight of the orange is waste with high potential to be used as bioenergy due to its lignocellulosic characteristics. In this sense, the purpose of the present work was to characterize and dry orange pomace based on the structure present in the citrus residue, formed by epicarp, mesocarp and endocarp. Firstly, the samples were characterized according to immediate and compositional analysis, FTIR and XRD. For drying, a convective dryer was used, where experiments were carried out under operating conditions varying the air speed (1.0 m/s – 1.8 m/s) and air temperature (between 60 ºC and 80 ºC). The biomass presented initial humidity above 72% for the different parts, which consisted of the epicarp, mesocarp and endocarp, however, with variations between the volatile contents (93.26 – 96.61%), ash (2.86 – 72% ) and fixed carbon (between 0.15 and 3.93%). For the compositional analysis, extractive results varied from 5.44 to 17.71% for lignin; 27.41 to 42.45% for holocellulose; 15.31 to 23.83% alpha-cellulose and 8.66 to 18.65% hemicellulose. Thermogravimetric (TG) and derived thermogravimetry (DTG) analyzes were used, which identified three stages of thermal degradation, referring to moisture loss and degradation of hemicellulose, cellulose and lignin. During drying, it was observed that the increase in temperature and air speed influenced mass transport, but internal resistance to diffusion was predominant. The simulation of drying data showed that the Page model was selected as the most appropriate to predict the drying phenomenon with R2 close to unity and with mean square deviations lower than 0.006. The results obtained in this work are of great relevance for predicting the behavior of each lignocellulosic biomass during the convective drying process as well as its physical, chemical and thermal characteristics, being considered promising for energy purposes.
Casca de café como recurso renovável para a produção de celulases via fermentação em estado sólido com Aspergillus fumigatus
(Universidade Federal do Espírito Santo, 2024-04-23) Vasconselos, Patrícia Garcia; Coelho, Jussara Moreira; https://orcid.org/; http://lattes.cnpq.br/; Co-orientador2; https://orcid.org/; http://lattes.cnpq.br/; Silva, Wellington Betencurte da ; http://lattes.cnpq.br/; Orientador2; https://orcid.org/; http://lattes.cnpq.br/; https://orcid.org/; http://lattes.cnpq.br/; Dutra, Julio César Sampaio ; https://orcid.org/; http://lattes.cnpq.br/; Carvalho, Raquel Viera de ; https://orcid.org/; http://lattes.cnpq.br/; Maitan-Alfenas, Gabriela Píccolo ; https://orcid.org/; http://lattes.cnpq.br/; 4º membro da banca; https://orcid.org/; http://lattes.cnpq.br/; 5º membro da banca; https://orcid.org/; dc.contributor.referee5Lattes; 6º membro da banca; https://orcid.org/; http://lattes.cnpq.br/; 7º membro da banca; https://orcid.org/; http://lattes.cnpq.br/
Coffee is one of the main commodities produced by Brazil, and during the processing of the fruits, approximately 50% of the It are discarded in the form of waste. An alternative for reusing this residue is its application as a substrate in solid state fermentation (SSF) to obtain products with high added value, such as cellulases. In this context, the present work aimed to evaluate the potential of fresh coffee husk and pre-treated by alkaline solution in microwave, as an inducer in the production of cellulases by SSF using the fungus Aspergillus fumigatus. Cultivation conditions related to moisture content (50 – 70 %) and substrate content (60 – 80 %) were evaluated using a DCCR experimental design. Tests with in natura and pre-treated CC obtained FPase activities of 1,046 U/gms and 2,315 U/gms, respectively, after 120 hours of FES under conditions of 70 % CC and 70% humidity. Statistical analyzes demonstrated that moisture content is the parameter with the greatest influence on cellulase production by A. fumigatus, and conditions of 68 to 70% provide greater FPase activities. Enzymatic partial characterization showed that the crude enzyme extract has stability under conditions of pH 5 – 6 and 40 – 60 °C. In addition, Cu2+ , Co2+ , and Mn2+ ions can be used as cofactors. The enzymatic hydrolysis test of CC with the crude enzyme extract provided 1,5 g/L reducing sugars after 48 hours. These results highlight the potential of cellulases produced by A. fumigatus for industrial applications
Catalisador ternário de PtRhSn0² disperso em carbono aplicado na reação de eletro-oxidação de glicerol
(Universidade Federal do Espírito Santo, 2017-09-06) Junco, Gustavo Garcia; Profeti, Demetriu; Profeti, Luciene Paula Roberto; Pinheiro, Christiano Jorge Gomes; Altoé, Mário Alberto Simonato
Currently, there is extensive discussion about energy issues, and due to the great apprehension related to the pollution generated by the use of fossil fuels and their probable scarcity, it is interesting to develop methods capable of supplying energy from renewable sources. Several research groups aim to develop fuel cells (FC’s) that operate with hydrogen or alcohols as fuel. However, a catalyst for direct alcohol fuel cell (DAFC) with high catalytic efficiency, tolerant to COads species poisoning and low cost was not found yet. In this work, PtRhSnO2/C electrocatalysts were developed and the results of electrochemical characterization using cyclic voltammetry (VC) showed that this catalyst has a profile similar to the polycrystalline platinum catalyst. These tests also allowed to identify the greater stability of PtRhSnO2/C in alkaline medium. The experiments performed by CV and chronoamperometry (CA) showed that the PtRhSnO2/C electrodes without thermal treatment (TT) and with TT had good catalytic activity for the electrooxidation of glycerol 0.5 mol L -1, since they demonstrated superior results to those obtained by the commercial platinum electrode (Pt/C 30% of E-TEK). It is important to note that the catalyst treated at 500 °C showed the best results in the tests performed by CV and CA. Also in this work, it was observed that the activation energy of the PtRhSnO2/C catalyst without TT decreases with the increase of temperature during the electrooxidation of glycerol. By means of the kinetic study, it was verified that PtRhSnO2/C without TT has less activation energy when compared to Pt/C 30% of E- TEK.
Comparação entre os resíduos finos recém-gerados e os depositados em aterros da indústria de rochas ornamentais
(Universidade Federal do Espírito Santo, 2019-02-25) Silva, Tatiane Brito Perim da; Neves, Mirna Aparecida; Borges, Simone Pereira Taguchi; Profeti, Luciene Paula Roberto
The ornamental rock sector produces a significant amount of fine residues. Existing studies on the classification of these residues are still inconclusive. While some works consider them as Non-Inertes, others classify them as Inertes and even Dangerous. Another point that must be highlighted is the waste that has been deposited for several years and that also need to be studied in order to identify possible changes in its behavior with the environment. This study aimed to know the effect of aging of the fine residues generated by ornamental stone processing. Two moments were studied: the new residues (NRs) and the old residues (ORs). The samples were characterized according to size distribution, mineralogy, chemical composition and scanning electron microscopy (SEM). The classification of the residues followed the standards 10004, 10005 and 10006 of ABNT (2004). Regarding the characterization, no significant differences were observed between the studied cases; however, regarding the classification, it was observed that the behavior of the constituents of the residues changes over time, the concentrations of the analyzed parameters are higher in the NBs and tend to decrease in the RAs, from Non-Inertes (Class IIA) to Inertes (Class IIB).

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