Navegando por Autor "Nascimento, Claudio Augusto Oller do"
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Artigo Estudo da caracterização da borra de petróleo e processo de extração do óleo(Associação Brasileira de Engenharia Sanitária e Ambiental - ABES, 2016) Chiavone Filho, Osvaldo; Guimarães, Adriana Karla Virgolino; Nascimento, Claudio Augusto Oller do; Teixeira, Antonio Carlos Silva Costa; Melo, Henio Normando de SouzaNesse trabalho, objetivou-se recuperar o óleo presente na borra oleosa por processo de extração, a fim de reutilizá-lo como combustível. Foram aplicados dois planejamentos experimentais: fatorial fracionado e Doehlert. Através da caracterização da borra oleosa (análises físico-químicos, elementar CHN e S, orgânicas e inorgânicas), constatou-se que a borra oleosa utilizada é constituída de 36,2% de óleo, 16,8% de cinzas, 40% de água e 7% de compostos voláteis. A eficiência média do processo de extração foi 70%. Entretanto, a análise estatística mostrou que o modelo quadrático não se ajustou bem ao processo, devido à complexidade do material estudado. Por outro lado, aplicando-se a modelagem de RNA, o coeficiente de determinação foi de 87,5%, mostrando-se bastante satisfatórioArtigo Rapid mineralization rate of acetylsalicylic acid in a tubular photochemical reactor: the role of the optimized excess of H2O2(Elsevier, 2019-10) Silva, Douglas do Nascimento; Cunha Filho, Fernando José Vieira da; Lima, Andressa Mota; Ratkievicius, Luciana Avelino; Silva, Danielle Jaiane; Chiavone Filho, Osvaldo; Nascimento, Claudio Augusto Oller doAcetylsalicylic acid (ASA) is a model pollutant and a representative of the emerging pharmaceutical micro- pollutants whose mineralization across several advanced oxidative processes takes hours to complete. This work devotes to optimize and understand the kinetic conditions to mineralize ASA using Photo-Fenton process with UVA radiation in a tubular photochemical reactor. The optimization employs a statistical tool termed factorial design (FD) that studies how the concentrations of ASA, Fe2+ and H2O2 affects the mineralization over a larger interval of concentrations. The factorial design indicates that the initial concentration of H2O2 is a crucial variable to achieve a fast rate of ASA mineralization. Using optimized contents of both H2O2 and Fe2+ (45 Mm and 1.5 mM, respectively) in the Photo-Fenton process (H2O2/Fe2+/UVA), mineralization around 90% is reached in about 10 min, the fastest rate ever observed, enabling to treat 0.012 m3 h−1 per tubular reactor. The underlying reason for such outstanding performance is attributed to the optimized 4.5-folds excess of [H2O2], i.e.the ratio of H2O2 concentration used at the initial time to that required for complete mineralization of the theoretic TOC. Measurements of the remaining concentration of H2O2 strongly indicates that excess of [H2O2] optimizes the instantaneous concentration of radical % OH. As a conclusion, the stoichiometric excess of [H2O2] is an important parameter to be optimized for achieving the highest degree of mineralization at the shortest time when using the photochemical reactor, in turn, decreasing costs related to the total energy consumed both by the lamp and by the recirculation pumpArtigo Synthesis of porous zinc aluminate spinel (ZnAl2O4) by metal-chitosan complexation method(Elsevier, 2014-03-05) Chiavone Filho, Osvaldo; Stringhini, Fabiane Marconato; Foletto, Edson Luiz; Sallet, Daniela; Bertuol, Daniel Assumpção; Nascimento, Claudio Augusto Oller doZinc aluminate (ZnAl2O4) particles with a spinel structure were prepared by metal-chitosan complexation method. The solids were obtained by the thermal decomposition of precursor compound of metallic hydroxides mixture and the biopolymer chitosan. X-ray diffraction analysis (XRD), Fourier transform infrared spectroscopy (FTIR), X-ray fluorescence (XRF), scanning electron microscopy (SEM) and N2- adsorption–desorption isotherms were used for the characterization of the products. The results showed that the ZnAl2O4 spinel can be obtained by heating the precursor at temperatures above of 500 C, resulting in a material with porous structure and large surface area and high purity