ABSTRACT
Abstract This work reports the study of the potential application of Zn/TiO2 catalysts, obtained by the sol-gel method, in processes of environmental decontamination through the reactions of photodegradation of textile dye, followed by electrospray mass spectrometry. The catalysts synthesis was performed according to a 2² factorial design with repetition at the central point. The characterization techniques used were: N2 adsorption measurements (BET method), scanning electron microscopy with energy dispersive X-ray (MEV/EDS), X-ray diffraction and point of zero charge (PZC). The photocatalytic tests were performed in batch in the presence of sunlight, and to evaluate the degradation kinetics study, a rapid direct injection electrospray mass spectrometry (DI-ESI-MS) method has been developed. By the photocatalytic tests, the calcination temperature of 400 °C has shown the best results of discoloration for the reactive Orange-122 dye (99.76%) in a reaction time of 2h. The discoloration kinetics were a pseudo-first order, and a statistical analysis was performed to investigate the effects of the variables and to optimize the conditions of discoloration to the dye. After the reactional time of 2 h, an ion of m/z 441.5 was detected by ESI-MS, indicating that the photocatalytic process was effective for the degradation of the dye to secondary compounds.
Subject(s)
Azo Compounds/toxicity , Biodegradation, Environmental , Decontamination/methods , Tandem Mass Spectrometry/methods , Environmental Restoration and Remediation/methods , Wastewater , Photochemistry , Textiles/toxicity , Microscopy, Electron, Scanning , Catalysis , Catalytic Domain , Spectrometry, Mass, Electrospray Ionization , Coloring Agents , Photobioreactors , Models, TheoreticalABSTRACT
O objetivo deste trabalho foi desenvolver bebida fermentada à basede extrato hidrossolúvel de quinoa, determinar sua composição centesimal e realizar a avaliação sensorial e microbiológica do produto. Para o processo fermentativo foram utilizadas cepas desidratadas de Streptococcus thermophilus e Lactobacillus delbrueckii subsp. bulgaricus. O extrato hidrossolúvel de quinoa fermentado sem a adição de polpa de fruta e sacarose foi submetido às determinações de umidade, cinzas, lipídios, proteínas e carboidratos. Realizou-se o teste de aceitação e a avaliação microbiológica dos produtos,incluindo as determinações de coliformes totais, coliformes a 45ºC e Salmonella. O produto desenvolvido alcançou boa aceitação e atendeu aos padrões microbiológicos da legislação brasileira vigente. Concluiu-se que a bebida fermentada de extrato hidrossolúvel dequinoa constitui boa alternativa para a substituição de bebidas lácteas e à base de soja.