EAJ - Artigos publicados em periódicos
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Artigo Study of High-Density Polyethylene (HDPE) kinetics modification treated by Dielectric Barrier Discharge (DBD) plasma(MDPI, 2020-10-21) Feitor, Michelle Cequeira; Medeiros Neto, João Freire de; Souza, Ivan Alves de; Targino, Talita Galvão; Diniz, Gutembergy Ferreira; Libório, Maxwell Santana; Sousa, Rômulo Ribeiro Magalhães; Costa, Thércio Henrique de CarvalhoIn this work, the plasma was used in the dielectric barrier discharge (DBD) technique for modifying the high-density polyethylene (HDPE) surface. The treatments were performed via argon or oxygen, for 10 min, at a frequency of 820 Hz, voltage of 20 kV, 2 mm distance between electrodes, and atmospheric pressure. The efficiency of the plasma was determined through the triple Langmuir probe to check if it had enough energy to promote chemical changes on the material surface. Physicochemical changes were diagnosed through surface characterization techniques such as contact angle, attenuated total reflection to Fourier transform infrared spectroscopy (ATR-FTIR), X-ray excited photoelectron spectroscopy (XPS), and atomic force microscopy (AFM). Plasma electronics temperature showed that it has enough energy to break or form chemical bonds on the material surface, impacting its wettability directly. The wettability test was performed before and after treatment through the sessile drop, using distilled water, glycerin, and dimethylformamide, to the profile of surface tensions by the Fowkes method, analyzing the contact angle variation. ATR-FTIR and XPS analyses showed that groups and bonds were altered or generated on the surface when compared with the untreated sample. The AFM showed a change in roughness, and this directly affected the increase of wettabilityArtigo Optical-electrical properties and thickness analysis of TiO2 thin films obtained by magnetron sputtering(Springer Science and Business Media LLC, 2020-09-23) Feitor, Michelle Cerqueira; S. Sobrinho, V. S.; Miranda Neto, José Queiroz de; Lima, L. L. F.; Souza, Iedo A; Libório, Maxwell Santana; Queiroz, José César Augusto de; Sousa, Rômulo Ribeiro Magalhães de; Almeida, Érika Oliveira de; Costa, Thércio Henrique de CarvalhoThe study of thin films with properties that meet specific needs and improve people’s quality of life has been the focus of many researchers. However, knowing and controlling the production techniques of these films have been a challenge for the industry of optical-electronic devices, functional coatings, and energy conservation. The thickness of thin films is a parameter that influences the optical and electrical characteristics of these materials, thus being one of the most important information in the plasma deposition process. Because of the need for precision in measuring the thickness of thin transparent films, this work proposes to evaluate the Swanepoel methods (envelope) and the PUMA, computational method, from optical transmittance curves and compare them with the measurements directly made by microscopy. Scanning electronics for thin films of TiO2 deposited by magnetron sputtering in different conditions. The results of this study showed that the PUMA method is capable of calculating film thicknesses of a few hundred nanometers and with few interference fringes. The PUMA method showed convergence with high precision for films produced with 30 and 60 min of treatment and a difference of 17% for films with 120 min of deposition concerning the measurements made by microscopyArtigo Structural and optical properties of ZnO: Al thin films produced by magnetron sputtering with different oxygen flow: an experimental and Ab initio study(Wiley, 2020-08-05) Feitor, Michelle Cerqueira; Queiroz, José César Augusto de; Azevedo Filho, João Batista de; Libório, Maxwell Santana; Santos, Edson José da Costa; Souto, Ulisses Borges; Sousa, Rômulo Ribeiro Magalhães de; Costa, Thércio Henrique de CarvalhoThis work addresses, in an experimental and theoretical way, the influence of different oxygen pressure values on the physical and electronic properties of thin conductive and transparent oxide films of Al-doped ZnO, with different thicknesses. A series of characterization techniques, which include X-ray diffraction (XRD), scanning electron microscopy (SEM), atomic force microscopy (AFM), optical spectrophotometry, and Hall measurements are conducted. All films have a hexagonal wurtzite structure characteristic of ZnO, with preferential orientation along the plane (002) and transmittance values, in the visible range, greater than 80%. The increase in flow oxygen up to 25% provides an increase in the film’s density resulting in a decrease in electrical resistivity from 9.58 103 Ω cm to 8.14 103 Ω cm. The ab initio calculations allow to observe the distortions in the microstructure of the films attributed to the presence of impurities and to obtain the values of the total and formation energies. The values of the Mulliken population and chemical bond length are notoriously influenced by the concentration of oxygen in the atmosphere. The displacement of the valence band (VB) and the Fermi level, together with the decrease in the gap energy, reinforce the influence of oxygen gas on the electronic structure of the filmsArtigo Application of nitriding and duplex treatment on steel drills-HSS(JMEST, 2020-04) Feitor, Michelle Cequeira; Serra, Petteson Linniker Carvalho; Sousa, Rômulo Ribeiro Magalhães de; Barros Neto, João Rodrigues de; Libório, Maxwell Santana; Costa, Thércio Henrique de CarvalhoThe present study aims to evaluate the application of plasma nitriding (at temperatures of 450° and 500°C) and duplex treatment (conventional nitriding followed by TiN deposition, using the cathodic cage deposition technique). Samples were characterized by Vickers Microhardness Test, Scanning Electron Microscopy-SEM, and Energy Dispersion Spectroscopy-EDS. Drill performance was evaluated after machining SAE1045 steel specimens, using flank wear and hole diameter measurements. The performance test pointed to the viability of the treatment at 450°C, whose treated drill had a longer life than in the untreated drill, in addition to meeting the dimensional quality in all holes. In contrast, the other tools, nitrided at 500°C and submitted to the duplex treatment, they presented performance below the expected, not showing viability for application in these conditions. Additionally, it was observed the existence of a thermal gradient formed during the treatmentArtigo Surface modification of PET fabric by plasma pre-treatment for long-lasting permethrin deposition(Wiley, 2020-05-18) Feitor, Michelle Cequeira; Badaro, Adair Divino da Silva; Libório, Maxwell Santana; Souza, Flaviane camara de; Sousa, Rômulo Ribeiro Magalhães; Santos, Rayane Saory Medeiros dos; Costa, Thércio Henrique de Carvalho; Naeem, Muhammad; Iqba, JavedThe mosquito-transmitted diseases are of serious concern and are affecting several millions of peoples worldwide. Instead of medication afterward the disease initiated, self-protection against the mosquito's is preferable, specifically in endemic areas. For this purpose, the permethrin coated clothing is a suitable choice to avoid mosquitos' bites. Unfortunately, the permethrin coating on fabrics is not long-lasting, and its laundering resistance is very low on hydrophobic fabric. In this study, the effect of plasma surface modification of PET fabric on the adhesion of permethrin and its laundering resistance are evaluated. The plasma processing is carried out in nitrogen, oxygen, and nitrogen–oxygen mixture plasma. The samples are analyzed using Fourier Transform Infrared spectroscopy, X-ray photoelectron spectroscopy, scanning electron microscope and chromatography. The results show that the oxygen plasma pre-treated samples exhibit the higher residual contents of permethrin after 60 wash cycles as compared with other gasses. Without plasma pre-treatment, the 95% loss, whereas the sample with oxygen plasma pre-treatment shows that only 22% loss of initial concentration of permethrin occurs after washing. This study shows that plasma pre-treatment is valuable to improve the absorption of permethrin in PET and its laundering-resistance. As plasma treatment is a cost-effective technique, it needs less processing time and eco-friendly, thus it is a great choice to deposit long-lasting permethrin coating by plasma pre-treatment, instead of conventional binding agents. Remarkably, the plasma treatment technique is a well-established and industrially acceptable technique, thus expected to be of noteworthy importance for insecticide garments manufacturersArtigo Synthesis and characterization of ZnO/ZnAl2O4/ Zn2TiO4 composite films by AreO2 mixture hollow cathode glow discharge(Elsevier, 2021) Feitor, Michelle Cequeira; Queiroz, José César Augusto de; Naeem, Muhammad; Azevedo Filho, João Batista; Libório, Maxwell Santana; Queiroz, M. G. O.; Sousa, R. R. M.; Melo, E. B.; Costa, Thércio Henrique de CarvalhoIn this study, ZnO/ZnAl2O4/Zn2TiO4 composite nanostructured thin films are deposited assisted with hollow-cathode glow discharge (HCD). The films are deposited using various argon-oxygen gases mixture (0e50% O2), and its effect on film quality, optical and electrical properties is examined. Remarkably, instead of metallic targets, ZnO, TiO2, and Al2O3 powders filled in hollow-cathode are used for deposition, and thus no specific metallic targets are required in this technique. The deposited films consist of hexagonal wurtzite ZnO structure, ZnAl2O4, and Zn2TiO4 phases, and the crystalline size of films increases for higher oxygen contents. The thickness of films reduced by increasing oxygen contents, and all deposited films exhibit transmittance higher than 82%. The carrier concentration and mobility increase, whereas resistivity decreases when a higher amount of oxygen is added. This study shows that HCD can effectively synthesize the composite film with good optical and electrical properties. Additionally, the film’s properties and elemental composition can be tuned by changing the gas composition, and thus, no separate target metallic materials with the specific composition are requiredArtigo The energetic characterization of pineapple crown leaves(Springer Nature, 2015-08-02) Melo, Marcus Antônio de Freitas; Braga, Renata Martins; Queiroga, T. S.; Calixto, Guilherme Quintela; Almeida, Hanna Nóbrega; Melo, Dulce Maria de Araújo; Freitas, Júlio César de Oliveira; Curbelo, Fabiola Dias da SilvaEnergetic characterization of biomass allows for assessing its energy potential for application in different conversion processes into energy. The objective of this study is to physicochemically characterize pineapple crown leaves (PC) for their application in energy conversion processes. PC was characterized according to ASTM E871-82, E1755-01, and E873-82 for determination of moisture, ash, and volatile matter, respectively; the fixed carbon was calculated by difference. Higher heating value was determined by ASTM E711- 87 and ash chemical composition was determined by XRF. The thermogravimetric and FTIR analyses were performed to evaluate the thermal decomposition and identify the main functional groups of biomass. PC has potential for application in thermochemical processes, showing high volatile matter (89.5 %), bulk density (420.8 kg/m3), and higher heating value (18.9 MJ/kg). The results show its energy potential justifying application of this agricultural waste into energy conversion processes, implementing sustainability in the production, and reducing the environmental liabilities caused by its disposalArtigo Comparison of kinetic study of CTMA+ removal of molecular sieve Ti-MCM-41 synthesized with natural and commercial silica(ABM, ABC, ABPol, 2015) Melo, Marcus Antônio de Freitas; Fontes, Maria do Socorro Braga; Melo, Dulce Maria de Araújo; Costa, Cintia de Castro; Braga, Renata Martins; Alves, José Antônio Barros Leal ReisThis work aimed to determine and compare the apparent activation energy, involved in thermal decomposition of CTMA+ from the pores of Ti-MCM-41 synthesized by two different source of silica in order to evaluate their influence in the template removal. The molecular sieves Ti-MCM-41 were synthesized using rice husk ash (RHA), as alternative low cost source of silica, and commercial silica gel, obtaining two mesoporous material by hydrothermal synthesis of gel molar composition of: 1.0 CTMABr: 4.0 SiO2 : X TiO2 : 1.0 Na2 O: 200.0 H2 O. The samples were characterized to compare its properties by X-ray diffraction, IR spectroscopy, BET method and thermogravimetric analysis (TGA). The kinetic study using the model proposed by Flynn and Wall to determine the apparent activation energy for CTMA+ removal was performed using TGA data. The thermogravimetric analysis results of the material obtained from RHA confirmed intrinsic properties of mesoporous MCM-41 as the synthesized with commercial silica gel, such as high specific area, mesoporous range of pore diameter and hexagonal structure. According to the kinetics results the RHA showed similar chemical interaction to commercial silica gel, which makes it an interesting material, since it is a low cost source of natural silica from agricultural wasteArtigo Catalytic upgrading of Elephant grass (Pennisetum purpureum Schum) pyrolysis vapor using WO3 supported on RHA and RHA-MCM-41(Elsevier, 2017-01-01) Melo, Marcus Antônio de Freitas; Braga, Renata Martins; Melo, Dulce Maria de Araújo; Vitor Sobrinho, Eledir; Barros, Joana Maria de Farias; Carvalho, Alexandre Fontes Melo de; Fontes, Maria do Socorro Braga; Freitas, Júlio César de OliveiraRecently, zeolites have been widely applied in catalytic pyrolysis to improve physical and chemical properties of bio-oil to produce energy or to selectively produce chemicals for industry. This study aims to analyze the catalytic pyrolysis products of Elephant Grass (EG) using WO3 catalysts supported on rice husk ash (RHA) silica and RHA-MCM-41, being low cost materials derived from agro industrial waste, and evaluate the catalysts activity in the formation of deoxygenated compounds. Elephant Grass has been shown as a potential energy crop that has fast growth and is easy to cultivate in different countries, including Brazil. Its energetic characterization was evaluated by proximate and ultimate analysis, High Heat Value (HHV), cellulose, hemicellulose and lignin content, chemical ash composition by FRX and bulk density. Pyrolysis analysis was performed at 500 ◦C in a Py-5200 HP-R connected to a GC–MS, and pyrolysis vapors were carried by N2 to a catalytic bed at 400 and 600 ◦C. It was noticed that increasing catalyst temperature promotes cracking reactions leading to increased aromatic content. The main oxygenated pyrolysis products of EG such as phenols, furans, ketones and acetic acid were converted at 600 ◦C using WO3/RHA catalyst into aromatics (benzene, toluene, xylene, styrene), being of high added value for chemical industry. The main influence on aromatics yields could be related to catalytic activity of WO3 promoted by its redox ability and the rise in temperature which favors cracking reactionsArtigo Efeito de diferentes fontes de sílica nos parâmetros texturais da peneira molecular MCM-41(Associação Brasileira de Cerâmica - ABCeram, 2016) Melo, Marcus Antônio de Freitas; Fontes, Maria S. B.; Melo, Dulce Maria de Araújo; Costa, Cíntia de Castro; Alves, J. A. B. L. R.; Silva, M. L. P.; Braga, Renata MartinsNas últimas décadas, pesquisas estão sendo desenvolvidas para obtenção de materiais eficientes e economicamente viáveis para aplicação em diversos setores da indústria. Os materiais mesoporosos da família MCM-41 estão entre os candidatos eficazes pela facilidade de síntese e estrutura que favorece uma gama de aplicações. O objetivo desse trabalho foi apresentar uma abordagem rítica das características e propriedades dos materiais mesoporosos do tipo MCM-41, enfocando nos aspectos estruturais. Além isso, foram discutidas as vantagens e desvantagens do uso de sílica comerciais e alternativas. As fontes de sílica comerciais analisadas foram sílica gel e TEOS; já as fontes de sílica alternativas foram cinza da casca de arroz, quartzo e pó de vidro. Os materiais analisados foram sintetizados pelo método hidrotérmico e caracterizados por DRX, FTIR, BET e TG. Os resultados apresentados comprovam a eficiência das fontes de sílica alternativas na síntese do MCM-41, pois os materiais apresentaram propriedades texturais dentro dos padrões exigidos. Dessa forma, eles estão aptos a serem testados na indústria em substituição aos MCM-41 sintetizados com fonte de sílica comercialArtigo Nickel catalyst supported on magnesium and zinc aluminates (MgAl2 O4 and ZnAl2 O4 ) spinels for dry reforming of methane(Associação Brasileira de Cerâmica - ABCeram, 2017) Melo, Marcus Antônio de Freitas; Araújo, Larissa Costa Barros de; Melo, Dulce Maria de Araújo; Barros, J. M. de F.; Braga, Renata Martins; Costa, C. de C.; Rodrigues, G.Materials such as MgAl2O4 and ZnAl2O4 assessed in the reaction of dry reforming of methane to produce syngas were synthesized by microwave-assisted combustion method using urea as fuel. Samples of synthesized oxides were calcined at 800 °C for 2 h and impregnated with 5% nickel. The impregnated samples were calcined at 850 °C for 4 h to obtain the desired phases. The results of the catalytic tests showed that the catalysts are active for the reaction of dry reforming of methane, and the catalyst that showed the best performance for methane conversion was 5% Ni/MgAl2 O4 calcined at 850 °C/4hArtigo Study of the reactivity by pulse of CH4 over NiO/Fe-doped MgAl2O4 oxygen carriers for hydrogen production(Elsevier, 2017-09-28) Melo, Marcus Antônio de Freitas; Medeiros, Rodolfo Luiz Bezerra de Araújo; Macedo, Heloísa Pimenta de; Figueredo, Gilvan Pereira de; Costa, Tiago Roberto da; Braga, Renata Martins; Melo, Dulce Maria de AraújoThe reactivity of Ni-based oxygen carrier (OC) was studied by CH4 pulse test. The MgAl2O4 spinel was synthesized by microwave assisted combustion method and Ni and Fe were added by wet impregnation method. The results of CH4 pulse test revealed that the OCs were more reactive for partial oxidation reaction. The XRD analysis of OCs after the test confirms the presence of NiO and MgAl2O4 without the secondary phases like NiAl2O4 and FeAl2O4. Among the OCs, Ni15Fe2MA was the most reactive producing the highest amounts of H2 and exhibiting good re-oxidation capacity, illustrating its potential for use in Chemical Looping Reforming (CLR). The high reactivity is associated to a change on the NiO-support interactionArtigo Characterization and pyrolysis of Chlorella vulgaris and Arthrospira platensis: potential of bio-oil and chemical production by Py-GC/MS analysis(Springer Nature, 2017-04-17) Melo, Marcus Antônio de Freitas; Almeida, Hanna Nóbrega; Calixto, Guilherme Quintela; Chagas, Bruna M. E.; Melo, Dulce Maria de Araújo; Resende, Fabio M.; Braga, Renata MartinsBiofuels have been seen as potential sources to meet future energy demand as a renewable and sustainable energy source. Despite the fact that the production technology of first-generation biofuels is consolidated, these biofuels are produced from foods crops such as grains, sugar cane, and vegetable oils competing with food for crop use and agricultural land. In recent years, it was found that microalgae have the potential to provide a viable alternative to fossil fuels as source of biofuels without compromising food supplies or arable land. On this scenario, this paper aims to demonstrate the energetic potential to produce bio-oil and chemicals from microalgae Chlorella vulgaris and Arthrospira platensis. The potential of these biomasses was evaluated in terms of physical-chemical characterization, thermogravimetric analysis, and analytical pyrolysis interfaced with gas chromatograph (Py-GC/MS). The results show that C. vulgaris and A. platensis are biomasses with a high heating value (24.60 and 22.43 MJ/kg) and low ash content, showing a high percentage of volatile matter (72.49 and 79.42%). These characteristics confirm their energetic potential for conversion process through pyrolysis, whereby some important aromatic compounds such as toluene, styrene, and phenol were identified as pyrolysis products, which could turn these microalgae a potential for biofuels and bioproduct production through the pyrolysisArtigo One-step synthesis of LaNiO3 with chitosan for dry reforming of methane(Elsevier, 2018-05-17) Melo, Marcus Antônio de Freitas; Oliveira, Ângelo Anderson Silva de; Medeiros, Rodolfo Luiz Bezerra de Araújo; Figueredo, Gilvan Pereira de; Macedo, Heloísa Pimenta de; Braga, Renata Martins; Maziviero, Fernando Velcic; Melo, Dulce Maria de Araújo; Vieira, Marcela MarquesThis paper presents a new preparation method of a catalytic precursor LaNiO3 perovskite type in one-step using chitosan as a chelating agent. During synthesis La and Ni nitrates were added into a solution containing chitosan, placed into an oven to decompose the reagents and subsequently calcined. The perovskite was characterized by X-ray diffraction (XRD), scanning electron microscopy with chemical microanalysis (SEM-EDS), temperature-programmed reduction (TPR) and thermogravimetric analysis (TGA). The catalytic tests were conducted in a space velocity of 18 Lh1 g1 at three temperatures: 600, 700 and 800C. The characterization results indicated the formation above 95% of LaNiO3 phase with good chemical homogeneity at lower temperature with metallic area and dispersion compatible with literature. The catalytic test results showed good levels of CH4 and CO2 conversions and good yields of CO and H2. Therefore, the described method is a simple, fast and low-cost route to prepare LaNiO3 for hydrogen production via dry reforming of methaneArtigo A comparative study of dry reforming of methane over nickel catalysts supported on perovskite-type LaAlO3 and commercial a-Al2O3(Elsevier, 2018-06-14) Melo, Marcus Antônio de Freitas; Figueredo, Gilvan Pereira de; Medeiros, Rodolfo Luiz Bezerra de Araújo; Macedo, Heloísa Pimenta de; Oliveira, Ângelo Anderson Silva de; Braga, Renata Martins; Mercury, José Manuel Rivas; Melo, Dulce Maria de AraújoA systematic and comparative study was made to determine the influence of perovskite-type LaAlO3 and commercial a-Al2O3 on the performance of nickel-based catalysts in dry reforming of methane (DRM). The perovskite-type LaAlO3 was selected due to its characteristics of solid state semiconductor with oxygen vacancies and high structural stability. The catalysts were characterized by X-ray diffraction (XRD), X-ray fluorescence spectroscopy (XRF), N2 adsorption-desorption, temperature programmed reduction (TPR-H2), thermogravimetric analysis (TGA), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The catalyst performance was evaluated based on activity tests (600e800 C) and short- and long-term stability (10 and 20 h) at 700 C at a GHSV (Gas Hourly Space Velocity) of 18 and 72 L g1 h1. The TPR-H2 profiles indicate that the oxygen vacancies on the perovskite surface exerted a strong effect on the reduction temperature and reducibility of the NiO nanoparticles, resulting in weak Ni0/support interaction. The results of the tests after 10 h under GHSV of 18 L g1 h1 indicate that the Ni/LaAlO3 catalyst is 7.8 and 11.5% more stable than Ni/a-Al2O3 in the conversions of CH4 and CO2, respectively. The higher stability and activity of Ni/LaAlO3 is directly ascribed to the presence of NiO (3.38 wt%) after activation, which promoted the formation of carbon nanotubes (CNT) and increased the dispersion of the metallic phase. Even under severe conditions of activation and reaction (high GHSV), as in the long-term test, the Ni/LaAlO3 catalyst showed a 37.2% higher H2 yield than the Ni/a-Al2O3. Analyses by TEM indicate that the Ni/a-Al2O3 catalyst exhibited deactivation problems associated with sintering effects. Thus, the presence of structural defects and surfaces rich in oxygen vacancies makes LaAlO3 perovskite a potential support for application in methane catalytic reforming processesArtigo Study of the reactivity of Double-perovskite type oxide La1¡xMxNiO4 (M 1⁄4 Ca or Sr) for chemical looping hydrogen production(Elsevier, 2018-01-18) Melo, Marcus Antônio de Freitas; Melo, Vítor Rodrigo de Melo e; Medeiros, Rodolfo Luiz Bezerra de Araújo; Braga, Renata Martins; Macedo, Heloísa Pimenta de; Ruiz, Juan Alberto Chavez; Moure, Gustavo Torres; Melo, Dulce Maria de AraújoLa2-xMxNiO4 perovskite oxygen carriers (OC) doped with Ca and Sr (x 1⁄4 0.05 and 0.20) in the site La were prepared by microwave assisted combustion method and calcined at 800 C for 2 h. A reactivity study was carried out applying pulses of H2, O2 and CH4. The reactions involved in each step, as well as H2 production, were studied to evaluate the redox properties of each OC. The crystalline structure, morphology, reduction and oxidation profiles were determined by XRD, SEM and TPR/TPO cycles, respectively. The results indicate that the dopant (Ca or Sr) strongly affect the structure and reactivity of the OC. The increase in dopant concentration increased the degree of crystallinity and the amount of the A2BO4 phase formed. The increase in dopant concentration decreased the reducibility of the perovskite. OCs doped with Ca showed higher conversion percentages, and also higher H2 production. In carriers doped with Sr no coke formation was observed.Artigo Renewable aromatics through catalytic flash pyrolysis of pineapple crown leaves using HZSM-5 synthesized with RHA and diatomite(Elsevier, 2019-04-01) Melo, Marcus Antônio de Freitas; Barbosa, Andrey da Silva; Siqueira, Lorena A. M.; Medeiros, Rodolfo Luiz Bezerra de Araújo; Melo, Dulce Maria de Araújo; Freitas, Júlio César de Oliveira; Braga, Renata MartinsThe influence of reactor temperature of 300 and 600 °C and the acidity of the ZSM-5 and HZSM-5 catalysts on the pyrolysis product yields of the pineapple crown leaves have been investigated in a fixed bed reactor Py-GC/MS. The ZSM-5 catalyst was hydrothermally synthesized with a Si/Al ratio 50, using residual diatomite and rice husk ash as alternative sources of Al and Si for catalyst cost reduction. For the HZSM-5 synthesis, calcined ZSM-5 was activated by ion exchange between Na+ and H+. The catalysts structure was confirmed by the XRD and Rietveld treatment, SEM, FTIR, FRX, TGA and BET results. Analytical pyrolysis of the biomass was carried out at 500 °C in a Py-5200 HP-R pyrolyzer connected to the GC/MS and the pyrolysis vapors were transported to a catalytic bed at 300 and 600 °C. The results showed that the increase in the catalytic bed temperature promoted increased the aromatic content. The main pyrolysis products of the PCL were oxygenated compounds that were converted at 600 °C using the HZSM-5 catalyst into high value renewable aromatic compounds for the chemical industry, such as benzene, toluene, xylene, etilbenzene, thereby confirming the deoxygenation activity of synthesized catalyst to produce renewable aromatics compounds which are important platform chemicals and precursors for jet fuels, gases, polymers and solventsArtigo One-pot microwave-assisted combustion synthesis of Ni-Al2O3 nanocatalysts for hydrogen production via dry reforming of methane(Elsevier, 2020-03-01) Melo, Marcus Antônio de Freitas; Medeiros, Rodolfo Luiz Bezerra de Araújo; Figueredo, Gilvan Pereira de; Macedo, Heloísa Pimenta de; Oliveira, Ângelo Anderson Silva de; Rabelo Neto, Raimundo C.; Melo, Dulce Maria de Araújo; Braga, Renata MartinsNi-based catalysts supported on Al2O3 were obtained via a simple, low cost and fast one-pot microwave-assisted combustion synthesis. The effect of fuel content (urea) was investigate. It was observed that the fuel ratio greatly influences the catalysts properties and performance. The results showed that the catalyst synthesized with low fuel content (Ni-LU) presented high specific surface area (265 m2/g), high degree of reduction and smaller nanometric Ni particles (~15 nm). In addition, the catalytic tests carried out at 700 °C for 20 h (GHSV = 72 Lh−1g−1) revealed high activity with low coke deposition. Further investigations were conducted on Ni-LU catalyst in order to better understand its catalytic properties. In-situ X-ray diffraction analysis (using synchrotron radiation) was used to evaluate the Ni particle size during the DRM, and indicated the sintering of Ni particles during the first hour of catalytic reaction. Furthermore, small amount of carbon nanotubes (CNT) with Ni particles encapsulated were observed by TEM analysisArtigo Influence of porosity in a packed-bed tubular reactor on biodiesel production from soybean oil and supercritical ethanol: an experimental and phenomenological investigation(American Chemical Society, 2019-07-31) Souza, Domingos Fabiano de Santana; Santiago, Luiz E. P.; Rebouças, Érica G.; Silva, Maxwell G.; Oliveira, Katherine C.; Jesus, Anderson A.; Aguiar, Emerson Moreira de; Oliveira, Jackson A.In the present study, the transesterification of soybean oil with ethanol under supercritical conditions was investigated using a packed-bed tubular reactor. The experiments were performed with an oil/alcohol molar ratio of 1:40, a pressure of 15 MPa, and different conditions of temperature (573−673 K), flow rate (0.5−1.0 mL/min), and bed porosity (0.32−1.0). A phenomenological model was developed to describe and analyze the results. The highest ester yield (98.99%) was obtained for the lower bed porosity (0.32), under 673 K and 0.5 mL/min with a residence time of 5.44 min. The kinetic and dispersion coefficients were estimated using the particle swarm optimization algorithm, and the model fitted the experimental data with an R2 coefficient of 0.97. The proposed kinetic model followed the behavior of the Arrhenius equations. Low values of dispersion were observed under conditions of lower flow rate and porosity. An analysis of the model allowed us to verify that the increase of the ester yield produced occurs at small values of the Reynolds number and high Peclet numbersArtigo Secagem da polpa de graviola pelo processo Foam-Mat e avaliação sensorial do produto obtido(UnP, 2015-08-10) Dieb, Judith Teixeira; Gurgel, Camilla Emanuelle Mendes Rocha; Dantas, Thayse Naianne Pires; Medeiros, Maria de Fátima Dantas deForam realizados ensaios de secagem em camada de espuma da polpa de graviola com adição de 1% de emustab e 1% de liga neutra. Estudou-se os efeitos da temperatura (50°C, 60°C e 70°C) e espessura da camada (0,30 cm, 0,45 cm e 0,60 cm) na cinética de secagem, avaliando-se o comportamento das curvas de secagem e as características físico - químicas do produto em pó (umidade e atividade de água). Iogurtes saborizados com 7% de pó de graviola obtidos na secagem foram submetidas à análise sensorial que foi realizada mediante teste de avaliação utilizando 50 provadores não treinados. Cada provador emitiu notas para os atributos aparência, odor, sabor e textura. O produto apresentou índice de aceitabilidade superior a 70% e conforme a classificação qualitativa, as médias das notas ficaram compreendidas entre gostei ligeiramente e gostei regularmente (6,63 a 7,55 para os atributos odor e textura, respectivamente)