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  • Author or Editor: M. J. B. Souza x
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Abstract

The thermo-programmed reduction study of Pt/WOx–ZrO2 materials prepared with different tungsten loading were performed by thermogravimetry. The samples were synthesized by impregnation method and calcined at 600, 700 and 800°C. The characterizations of both un-calcined and calcined materials were carried out using different techniques: thermal analysis (TG and DTA), X-ray diffraction (XRD) and thermo-programmed reduction (TPR). TG and DTA analysis of un-calcined were used to determination of calcination temperatures of the samples. XRD diffractograms were useful to help us in the determination of phase presents. TPR profiles showed between three and four events at different temperatures attributed to platinum reduction and the different stages of tungsten specie reduction.

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Journal of Thermal Analysis and Calorimetry
Authors: A. M. Ramalho, M. M. Conceiçăo, V. J. Fernandes Jr., J. C. Machado, L. E. B. Soledade, and A. G. Souza
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Abstract

This study aims to analyze thermal stability and make a rheological assessment of sunflower oil produced in the Northeast of Brazil, resulting from the pyrolysis process. Oil samples were submitted to thermal degradation and the reaction was evaluated by the thermogravimetric technique, at temperatures between 30 and 900 °C. Apparent activation energy was determined using the model-free kinetics theory. The coaxial cylinder system at operating temperature of 40 °C was used to obtain rheological parameters. Oil was characterized by gas chromatography. The lipid profile of the oil exhibited good quality. The activation energy of the sunflower oil was 201.2 kJ mol−1. Results showed the influence of physical–chemical characteristics of vegetable oil on the thermal decomposition process. Rheological analyses confirmed Newtonian rheological behavior. The high potential of the “Catissol” variety produced in Northeast Brazil as raw material for biofuel production using pyrolysis was also demonstrated.

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Journal of Thermal Analysis and Calorimetry
Authors: M. R. S. Silva, S. C. Souza, I. M. G. Santos, M. R. Cassia-Santos, L. E. B. Soledade, A. G. Souza, S. J. G. Lima, and E. Longo
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Journal of Thermal Analysis and Calorimetry
Authors: S. C. Souza, I. M. G. Santos, M. R. S. Silva, M. R. Cassia-Santos, L. E. B. Soledade, A. G. Souza, S. J. G. Lima, and E. Longo
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Journal of Thermal Analysis and Calorimetry
Authors: S. C. Souza, M. A. F. Souza, S. J. G. Lima, M. R. Cassia-Santos, V. J. Fernandes Jr., L. E. B. Soledade, E. Longo, A. G. Souza, and I. M. G. Santos
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Journal of Thermal Analysis and Calorimetry
Authors: J. A. Moura, A. S. Araujo, A.C. S. L. S. Coutinho, Joana M. F. B. Aquino, A. O. S. Silva, and M. J. B. Souza
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