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Projeto, construção, testes e operação de um extrator de óleos vegetais
(Universidade Federal de São Carlos, 2006-03-02) Tavares, Jaciomar Alves; Silveira, Ana Maria da; https://lattes.cnpq.br/4807254028571537; https://lattes.cnpq.br/3191021230710929
Brazil is a rich country in biodiversity holding a great variety of plants, being one of the main constituents - oil that has been searched by the industries, especially, pharmaceutic, food and cosmetic. Among the plants with these characteristics is the well -noted ginger, that has been used in treatments, from stomach to rheumatism problems, in culinary as condiments and also in perfumery. Depending on the importance and application of the essential oil, in literature, some types of extractors are found, being able to be cited the distillers of the types Clevenger, soxhlet and the one that uses supercritical CO2. Analyzing these extractors it was verified that these present advantages and disadvantages that motivated this work, that has as objective to develop, project, construct and operate an equipment that allows the extraction of the essential oils, using the principle of dragging through vapor and that makes it possible the manipulation of the variable pressure and temperature. The developed and constructed equipment is composed by a boiler, a chamber of extraction with three trays and a distiller, operating itself in the following conditions: pressure in boiler 1.2 kgf/cm² the 3,6 kgf/cm²; pressure in the chamber of extraction - 0,4 kgf/cm² the 3,6 kgf/cm²; temperature: 75°C 140°C; average outflow of distilled in 0,831l/h and a average outflow of water in the distiller of 125 l/h, trays - one, two and three and mass of ginger - 200g, 400g, 600g and 1200g. Optimum result gotten in this extractor was using three trays and mass of 400g of ginger, extracting a mass of 0,965g of oil, what it corresponds to a 1,7% text. In the comparison between these results and the gotten ones for the Clevenger, the extracted oil text was 2,77 and 1.70%, respectively, showing that the projected and constructed equipment extracted 63% more than the oil, in the same conditions and with 3 hours to less of operation.
Estudo de procedimentos analíticos para determinação de Cr(III) e Cr(VI) em amostras sólidas
(Universidade Federal de São Carlos, 2006-03-02) Matos, Wladiana Oliveira; Nóbrega, Joaquim de Araújo; https://lattes.cnpq.br/8833989058164529
The legislation is evolving towards the establishment of restrictions to the concentration of Cr(VI), the most toxic redox form of chromium, in solid materials. This aspect has stimulated the development of sample preparation procedures for redox speciation analysis of chromium in solid samples. In the work here described it was studied procedures for Cr(VI) extraction in solid samples using alkaline solutions. Molecular absorption spectrophotometry based on 1,5 - diphenylcarbazide as chromogenic reagent was used for the determination of Cr(VI). The quantification of Cr(III) was carried out by the subtraction of the total chromium concentration and the concentration of Cr(VI). The samples employed were: soils, cements, cementrelated materials, nutritional complements and metallic components. The extractor solution composed by 0.10 mol L-1 Na2CO3 presented good performance for solid samples. Tests of stability of Cr(VI) indicated that reduction of Cr(VI) to Cr(III) did not occur in the adopted extraction conditions, even in the presence of significant amounts of Cr(III). The diphenylcarbazide method presents good sensitivity for the determination of Cr(VI) in extracts, however the presence of organic matter in the soil samples caused interferences. The total chromium concentrations were determined using either FAAS or ICP OES after complete decomposition of the samples. Sample preparation procedure for total chromium determination was implemented according to the type of sample. Cement samples and cement-related materials were decomposed by fusion. On the other hand, all the other samples were microwave-assisted digested using high pressure vessels. The main limitation of the studied procedures is the evaluation of accuracy because of the lack of standard reference materials.