Encontrados 17 documentos, a visualizar página 1 de 2
Pachira aquatica fruits shells valorization: renewables phenolics through analy...
Correia,Luiz Augusto da Silva; Silva,Janduir Egito da; Calixto,Guilherme Quintela; Melo,Dulce Maria de Araújo; Braga,Renata MartinsABSTRACT: This research valorized Pachira aquatica Aubl.’s fruit shells (PAS) through its energetic characterization and flash pyrolysis for biofuels or chemicals production. The characterization was performed through proximate and ultimate analysis, bulk density, higher heating value (HHV), hemicellulose, cellulose and lignin content, thermogravimetric analysis and absorption spectra in the infrared region obt...
Performance evaluation of NiCo2O4 spinel as a catalyst for partial oxidation of...
Peres,Ana Paula da Silva; Lima,Andréia Cavalcante de; Barros,Bráulio Silva; Ruiz,Juan Alberto Chavez; Melo,Dulce Maria de AraújoABSTRACT The NiCo2O4 catalyst with spinel structure was prepared by a modified polymeric-precursor method using gelatin as an organic-directing agent. The obtained powder was characterized by XRD, TPR and tested on the partial oxidation of methane. The Rietveld analysis performed on the XRD pattern confirmed the crystallization of two phases, the spinel NiCo2O4, and a solid solution NixCo1-xO. TPR profile revea...
EFFECT OF PYROLYSIS HEATING RATE ON THE CHEMICAL COMPOSITION OF WOOD VINEGAR FR...
Medeiros,Lúcio César Dantas de; Pimenta,Alexandre Santos; Braga,Renata Martins; Carnaval,Tatiane Kelly de Azevedo; Medeiros Neto,Pedro NicoABSTRACT Among the parameters used in the biomass carbonization process, the heating rate is one of the most important. The objective of the present work was to assess the influence of different heating rates on the chemical composition of wood vinegar (WV) from two wood species. Dried disks of Eucalyptus grandis and Mimosa tenuiflora wood were used as raw material. Carbonization runs were carried out in a labo...
Effect of Urea Excess on the Properties of the MgAl2O4 Obtained by Microwave-As...
Carvalho,Luciene Santos; Melo,Vitor Rodrigo de Melo e; Vitor Sobrinho,Eledir; Ruiz,Doris; Melo,Dulce Maria de AraújoIn this paper, magnesium aluminate spinels were prepared by microwave-assisted combustion, using urea as fuel. In order to evaluate the effect of the urea excess used in the synthesis, its mass was added in a range of 1.0 to 2.5 times the stoichiometric amount required. The materials produced were characterized by TGA, FTIR, XRF, XRD, BET, SEM and TEM. The results demonstrated that magnesium aluminate spinel wa...
Characterization of ZnAl2O4 Spinel Obtained by Hydrothermal and Microwave Assis...
Macedo,Heloísa Pimenta de; Medeiros,Rodolfo Luíz Bezerra de Araújo; Medeiros,Amanda Lucena de; Oliveira,Ângelo Anderson Silva deIn this work, zinc aluminate spinel was prepared by two methods of directly synthesis (without calcination): microwave assisted combustion and hydrothermal method. The materials were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and N2-adsorption/desorption isotherms. The XRD patterns confirmed the formation of cubic ZnAl2O4 spinel structure with no secondary phases for both synth...
Synthesis of MgAl2O4 by Gelatin Method: Effect of Temperature and Time of Calci...
Figueredo,Gilvan Pereira de; Carvalho,Alexandre Fontes Melo de; Medeiros,Rodolfo Luiz Bezerra de Araújo; Silva,Francisco MarceloMagnesium aluminate can be obtained by the methods: ceramic method, sol-gel, co-precipitation, hydrothermal and combustion. However, this work presents a simple and low cost route to obtain MgAl2O4 through the gelatin method. The main objective was to use gelatin as an organic precursor and to verify the influence of temperature and time of calcination on the structural and morphological properties of obtained ...
Modulator Effect of Acetic Acid on the Morphology of Luminescent Mixed Lanthani...
Leite,Ana Karina Pereira; Barros,Bráulio Silva; Kulesza,Joanna; Nascimento,Jarley Fagner Silva do; Melo,Dulce Maria de AraújoThe control of the size and morphology of Metal-Organic Frameworks is a challenge that must be overcome to ensure the use of these materials in advanced applications. Mixed Lanthanide-Organic Frameworks (MLOFs) were synthesized via solvo(hydro)thermal method and then characterized by PXRD, IR, TG/DTA, SEM and PL spectroscopy. The effect of the modulator (acetic acid) on the morphological characteristics of the ...
Spectroscopic Properties of pigment Li2-xZn1-xPrxTi3O8
Câmara,Maria Suely Costa da; Spinelli,Adaiane; Longo,Elson; Azevedo,Luciano Nobrega; Costa,Asenete Frutuoso; Pimentel,Patricia MendonçaInorganic compounds doped with rare earths (Ce3+, Pr3+, Nd3+, Sm3+, Eu 3+, Gd 3+, Tb 3+, Tm3+) have been used in various applications including light-emitting devices such as fluorescent lamps, cathode ray tubes, lasers and inorganic pigments. In this study, Pr3+ is doped in spinel Li2ZnTi3O8 system and synthesized by the polymeric precursor method, which is based on the process developed by the Pechini, and ch...
Nickel-based Catalyst Precursor Prepared Via Microwave-induced Combustion Metho...
Barros,Braulio Silva; Kulesza,Joanna; Melo,Dulce Maria de Araújo; Kienneman,AlainNickel-based catalyst precursor for dry reforming of methane was successfully prepared by a self-combustion method. Three different amino acids: urea, glycine and citric acid were tested as fuels in the redox reaction with metal nitrates. For each fuel, a thermodynamic modeling of the combustion reaction was performed. The samples were characterized by X-ray diffraction (XRD), Thermogravimetric analysis (TG), S...
Effect of the Acid Treatment of Montmorillonite Clay in the Oleic Acid Esterifi...
Nascimento,Alexsandra Rodrigues do; Alves,José Antônio Barros Leal Reis; Melo,Marcus Antônio de Freitas; Melo,Dulce Maria de AraújoBiodiesel is a fuel renewable, biodegradable and environmentally correct fuel, which can be obtained from the esterification reactions, transesterification and pyrolisis. Montmorillonite is a clay mineral of the smectite group and are of great interest for industrial processes such as catalysis and adsorption. Acid activation of clay minerals is one of the most effective methods proposed to produce active mater...