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Impact of an external electron acceptor on phosphorus mobility between water an...
Martins, Gilberto; Peixoto, L.; Teodorescu, S.; Parpot, Pier; Nogueira, R.; Brito, A. G.The present work assessed the impact of an external electron acceptor on phosphorus fluxes between water-sediment interface. Microcosm experiments simulating a sediment microbial fuel cell (SMFC) were carried out and phosphorus was extracted by an optimized combination of three methods. Despite the low voltage recorded, ∼96 mV (SMFC with carbon paper anode) and ∼146 mV (SMFC with stainless steel scourer anode),...
Release of volatile compounds from polymeric microcapsules mediated by photocat...
Marques, Juliana Filipa Gouveia; Oiveira, L. Filipa; Pinto, Renato; Coutinho, Paulo J. G.; Parpot, Pier; Gois, J. R.; Coelho, J. F. J.; Magalhães, F. D.In this study we propose a suitable method for the solar-activated controlled release of volatile compounds from polymeric microcapsules bonded with photocatalytic nanoparticles. These reservoirs can find applications, for example, in the controlled release of insecticides, repellents, or fragrances, amongst other substances. The surfaces of the microcapsules have been functionalized with TiO2 nanoparticles.Upo...
Photocatalytic thin films coupled with polymeric microcapsules for the controll...
Oliveira, L. Filipa; Marques, Juliana Filipa Gouveia; Coutinho, Paulo J. G.; Parpot, Pier; Tavares, C. J.This work reports on the application of solar-activated photocatalytic thin films that allow the controlled-release of volatile agents (e.g., insecticides, repellents) from the interior of adsorbed polymeric microcapsules. In order to standardize the tests,a quantification of the inherent controlled-release of a particular volatile agent is determined by gas chromatography coupled to mass spectroscopy, so that ...
Células de combustível microbianas : um processo inovador para produção de ener...
Peixoto, L.; Martins, Gilberto; Amorim, D.; Parpot, Pier; Nogueira, R.; Brito, A. G.A produção de energia constitui uma base essencial para o desenvolvimento humano. Neste quadro, a capacidade de determinados microrganismos oxidarem matéria orgânica e transferirem eletrões para um ânodo e, por essa via, permitirem a produção direta de eletricidade representa uma efetiva oportunidade tecnológica. Este novo processo, designado por célula de combustível microbiana, constitui uma abordagem de prod...
Effect of NaCl additive on properties of aqueous PEG–sodium sulfate two-phase s...
Ferreira, Luísa A.; Parpot, Pier; Teixeira, J. A.; Mikheeva, Larissa M.; Zaslavsky, Boris Y.The concentrations of all components in the phases of aqueous two-phase polyethylene glycol–sodium sulfate system of a fixed composition with different concentrations of NaCl additive were determined. Solvatochromic solvent features of aqueous media in the phases of all the systems were characterized in terms of solvent dipolarity/polarizability, solvent hydrogen bond donor acidity and hydrogen bond acceptor ba...
Electrocatalytic oxidation of oxalic and oxamic acids in aqueous media at carbo...
Ferreira, Marta; Pinto, Mara F.; Soares, O. S. G. P.; Pereira, M. F. R.; Orfão, J. J. M.; Figueiredo, J. l.; Neves, Isabel C.; Fonseca, A. Maurício C.The electrochemical oxidation of oxalic and oxamic acids on multiwalled carbon nanotubes (CNT) and on monometallic (Pd and Pt) and bimetallic (Pd-Cu, Pt-Cu) catalysts supported on multiwalled carbon nanotubes was investigated using cyclic voltammetry. The electrodes were prepared by dispersion of the catalytic material on Toray carbon (CT) using a Nafion/water solution. The kinetic parameters of the reactions w...
Decolorization of the phthalocyanine dye reactive blue 21 by turnip peroxidase ...
Silva, Maria Cristina; Corrêa, Angelita D.; Amorim, M. T. Pessoa de; Parpot, Pier; Torres, Juliana A.; Chagas, Pricila Maria BatistaPeroxidases can be used in decolorization processes and the treatment of textiles effluents. This study evaluates the potential of the turnip peroxidase enzyme in the decolorization of the phthalocyanine textile dye Reactive Blue 21 (RB21). Some factors such as pH, the amount of H2O2 and the enzyme were evaluated in order to determine the optimum conditions for the enzyme performance. The reaction products form...
Actividades experimentais nas escolas através de uma interacção com a universidade
Queirós, A.; Bettencourt, A. P.; Carvalho, M. Alice; Parpot, Pier; Botelho, Gabriela; Neves, Isabel C.A forma como a ciência é ensinada nas escolas afecta profundamente a percepção que os estudantes têm do mundo que os rodeia e consequentemente a escolha de uma futura carreira nas ciências. Por outro lado, a abertura da escola à comunidade envolvente, proporciona as condições para a sua participação activa na vida escolar, assim como a promoção do sucesso escolar, através da formação integral dos alunos, dotand...
Influence of the temperature in the electronic transfer mechanism of Geobacter ...
Peixoto, L.; Santos, Andréa F. S.; Machado, Idalina; Sousa, Ana Margarida; Brito, A. G.; Parpot, Pier; Pereira, M. O.; Nogueira, R.Geobacter species are important in the reduction of metals (e.g. Fe, Mn) in soils and sediments and constitute one of the most effective microorganisms known to use electrodes as the sole electron acceptor in microbial fuel cells to generate electricity. G. sulfurreducens transfers electrons directly to the electrode from different external membrane cytochromes. Each cytochrome is associated with a range of el...
Kinetic study of the redox processes in carbon electrodes with Geobacter sulfur...
Peixoto, L.; Santos, Andréa F. S.; Machado, Idalina; Sousa, A. M. M.; Brito, A. G.; Parpot, Pier; Pereira, M. O.; Nogueira, R.Geobacter sulfurreducens is a bacteria that can transfer electrons directly to the electrode from different external membrane cytochromes. Each cytochrome is associated with a range of electrical potentials, being energetically more favourable than some others. Different growth conditions of the bacteria, such as temperature, may influence the prevalence of certain cytochromes in the external membrane. The aim ...
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