37 research outputs found

    Screening of supports for immobilization of commercial porcine pancreatic lipase

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    The aim of this work is to report the performance of different supports for the immobilization of commercial porcine pancreatic lipase. The immobilization tests were carried out in several types of Accurel, activated alumina, kaolin, montmorillonite, ion exchange resins and zeolites. The characterization of the supports showed differences in terms of specific area and morphology. The characteristics of the supports influenced the amount of enzyme adsorbed, yield of immobilization and esterification activity of the resulting immobilized catalyst. The clays KSF and natural and pillared montmorillonites presented potential for use as support for lipase immobilization in terms of yield and esterification activity. Yields of immobilization of 76.32 and 52.01% were achieved for clays KSF and natural montmorillonite, respectively. Esterification activities of 754.03, 595.51, 591.88 and 515.71 U.g-1 were obtained for lipases immobilized in Accurel MP-100, Amberlite XAD-2, mordenite and pillared montmorillonite, respectively

    A Social Sciences and Humanities research agenda for transport and mobility in Europe: key themes and 100 research questions

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    Transport and mobility systems need to be transformed to meet climate change goals and reduce negative environmental and social effects. Despite EU policies having targeted such problems for more than three decades, transitions have been slow and geographically uneven. For effective change to happen, transport and mobility research needs fresh perspectives and better integration of knowledge from the Social Sciences and Humanities. Based on a Horizon Scanning approach, which allowed for a great deal of openness and variety in scholarly viewpoints, this paper presents a novel research agenda consisting of 8 themes and 100 research questions that may contribute to achieving environmentally sustainable mobility transitions within Europe. This research agenda highlights the need to not only support technological solutions for low-carbon mobility, but the importance of transformative policies that include new processes of knowledge production, civic participation and epistemic justice. We contend that the agenda points to the need for further research on the dynamics of science-society interactions.publishedVersio

    Estudo da adsorção de compostos sulfurados empregando zeólitas contendo zinco

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    This paper deals with an adosrption of sulphur compounds employing zeolites containing zinc. The zeolites employed were commercial NaY and Beta. The zinc was incorporated in three levels: 0.5; 1.0 and 5%. The sulphur compounds studied were benzothiophene and dibenzothiofene. The results showed that both zeolites can be employed for adsorption of benzothiophene and dibenzothiophene. The Zn incorporation (0.5%) promotes an increase in zeolites adsorption ability. The DBT adsorbs more than BT, probably because it strongly interacts with zeolite structure. The BT adsorbs more in NaY than in beta probably because the NaY zeolite has a high intern volume. This is not observed for DBT

    Screening of supports for immobilization of commercial porcine pancreatic lipase

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    The aim of this work is to report the performance of different supports for the immobilization of commercial porcine pancreatic lipase. The immobilization tests were carried out in several types of Accurel, activated alumina, kaolin, montmorillonite, ion exchange resins and zeolites. The characterization of the supports showed differences in terms of specific area and morphology. The characteristics of the supports influenced the amount of enzyme adsorbed, yield of immobilization and esterification activity of the resulting immobilized catalyst. The clays KSF and natural and pillared montmorillonites presented potential for use as support for lipase immobilization in terms of yield and esterification activity. Yields of immobilization of 76.32 and 52.01% were achieved for clays KSF and natural montmorillonite, respectively. Esterification activities of 754.03, 595.51, 591.88 and 515.71 U.g-1 were obtained for lipases immobilized in Accurel MP-100, Amberlite XAD-2, mordenite and pillared montmorillonite, respectively

    Estudo de adsorção de compostos sulfurados utilizando um diesel comercial dopado com benzotiofeno e dibenzotiofeno

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    Desulphurization process by adsorption was studied employing a commercial diesel dooped with 1000 mg/L of benzothiophene and dibenzothiophene. The adsorbents materials employed were three types of activated alumina (acid, basic and neutral). For comparison, adsorption process was made also using oxidized diesel sample. The results showed that the adsorbents were selective for sulphur compounds removal from fuels. The contact time have influence in adsorption process achieving 80% of removal for not oxidized dibenzothiophene. The three studied alumina types showed similar behavior and a greater selective in dibenzothiophene adsorption than benzothiophene. Dibenzothiophene removal is more effective in samples not oxidized, whereas the benzothiophene was almost totally removed in oxidized sample

    Immobilization of porcine pancreatic lipase in zeolite MCM 22 with different Si/Al ratios

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    The use of zeolites as support for immobilization of enzymes has been a matter of great interest recently due to the potential properties of these materials. In this work, the MCM 22 zeolite with different Si/Al ratios (15, 25 and 50) was used as support for immobilization of porcine pancreatic lipase, assessing the effect of its structure on the immobilization yield and enzyme activity. Results showed that the material composition influenced significantly the immobilization process. Higher yields of immobilization and enzymatic activities were achieved when MCM 22 with Si/Al ratio of 25 was used as support. In general, results demonstrate the potential of MCM 22 as support for porcine pancreatic lipase immobilization
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