Browsing by Author "Debacher, Nito Angelo"

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    Influence of non-thermal plasma reactor geometry and plasma gas on the inactivation of Escherichia coli in water.
    (2021) Cubas, Anelise Leal Vieira; Ferreira, Franciele Mendonça; Gonçalves, Daniela Borges; Machado, Marina de Medeiros; Debacher, Nito Angelo; Moecke, Elisa Helena Siegel
    The inactivation of bacteria Escherichia coli (E. coli) by non-thermal plasma (NTP) was investigated using argon, air and 1:1 mixture of air/Ar as plasma gas on five different reactors. The experiments were carried out in triplicate in each reactor, using 60 mL of distilled water pre-inoculated with E.coli. The physical- chemical analysis of pH, conductivity, nitrite, nitrate and temperature were performed soon after of 10 min of NTP treatment. The microbiological analysis of E. coli inactivation was performed using 100 mL samples withdrawn from the plasma reactor after 10 min and compared with the positive and negative control test results. The best performance were achieved whit the NTP reactors working with the upper electrode in the gas phase using 1:1 air/Ar and air as plasma gas. The results are linked with the E. coli inactivation due to membrane rupture by the NTP discharge followed by the attack of the reactive species produced in the solution. The E. coli inactivation was only partial using argon as plasma gas and the direct barrier discharge reactors showed partial inactivation even when air was used as plasma gas.
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    Oil extraction from spent coffee grounds assisted by non-thermal plasma.
    (2020) Cubas, Anelise Leal Vieira; Machado, Marina de Medeiros; Bianchet, Ritanara Tayane; Hermann, Kênia Alexandra da Costa; Bork, Jonathan Alexsander; Debacher, Nito Angelo; Lins, Elisa Flores; Maraschin, Marcelo; Coelho, Daniela Sousa; Moecke, Elisa Helena Siegel
    Coffee is one of the most popular beverages in the world and around 50% of the processed coffee beans becomes waste as spent coffee grounds (SCG). These SCG contain up to 20% of oil, which can be recovered and used in many different processes, such as biodiesel production, cosmetics and pharmaceuticals. The extracted oil contains large amounts of antioxidants, anti-inflammatory agents and immunomodulators, in addition to fatty acids that have excellent emollient and moist- urizing properties. It is therefore of interest to improve the oil extraction technique, to enhance the efficiency, reduce the extraction time and improve the quality of the oil extracted. Thus, in this study, a new technique for SCG oil extraction, using a non-thermal plasma technology as a pre-extraction procedure prior to Soxhlet extraction, was investigated, aiming to improve the extraction efficiency and oil quality. For comparison purposes, experiments were also carried out using an ultrasound pre-extraction procedure prior to Soxhlet extraction. It was observed that the use of pre-extraction with the plasma more than double the extraction yield compared with the Soxhlet extraction alone. Also, it increased the yield by around 30% compared with the use of ultrasound as the pre-extraction procedure. Analysis of the oil extracted by GC–MS showed that the quality of the oil composition was maintained. Also shows an increase in the antioxidant potential, which can prevent the harmful effects of ultraviolet (UV) radiation on the skin, due to their antioxidant, anti-inflammatory and immunomodulatory properties. The SEM images showed significant changes in the walls of the polyhedral cells of the spent coffee grounds after non-thermal plasma pre-treatment.