RODRIGO FERNANDO BRAMBILLA DE SOUZA

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2019 - 201912020 - 20231
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Âmbito: Nacional × Autor: CAMILA MARINHO GODOI SANTOS ×

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    Artigo IPEN-doc 29694
    Effective phosphate removal from water by electrochemically mediated precipitation with coffee grounds biocarbon obtained by non-thermal plasma method
    2023 - SILVESTRIN, G.A.; GONCALVES, M.H.; GODOI, C.M.; MAIA, V.A.; FERREIRA, J.C.; GUILHEN, S.N.; NETO, A.O.; SOUZA, R.F.B. de
    This study investigates the use of biocarbon electrodes, produced from coffee grounds through plasma pyrolysis, in the electrochemically mediated precipitation process for phosphorus removal in a flow reactor. The structural and electrochemical properties of biocarbon were analyzed using X-ray powder diffraction (XRD), Raman spectroscopy, and cyclic voltammetry. The results show that biocarbon consists of both graphene oxide and lignocellulose with surface OH groups that facilitate the breakdown of water, a key step in the electrochemically mediated precipitation process for phosphorus removal. The addition of graphite to the biocarbon paste was found to be necessary to obtain a response from the biocarbon in cyclic voltammetry. The Gr75BC25 electrode achieved higher phosphorus removal rates than other tested electrodes, particularly at low flows, due to the functional groups present in biocarbon enhancing the breakdown of water. However, electrodes with a greater amount of biocarbon exhibit lower rates of phosphorus removal and higher consumption of electrical power, which can be attributed to their higher electrical resistivity. Thus, to optimize its use, it is important to balance the benefits of increased phosphorus removal rates with the trade-off of increased energy consumption and decreased phosphorus removal at higher levels of biocarbon. The results suggest that biocarbon produced from coffee grounds by plasma pyrolysis has the potential to be used as an effective electrode material for electrochemically mediated precipitation processes.
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    Resumo IPEN-doc 26798
    Development of non-fluorinated membranes based on PBI for application in high temperature fuel cells (HT-PEM)
    2019 - SILVA, R.P.; SOUZA, R.F.B. de; SANTOS, C.M.G.; SILVA, A.J.; SANTIAGO, E.I.
    Most of Proton Exchange Membrane Fuel Cells (PEMFCs) use the Nafion as electrolyte, which has a limitation in the operating temperature. Usually, these cells operate up to 80°C since the proton conduction is dependent on water molecules carriers. The increase in the operating temperature of a PEMFC cell is desired due to the contribution of the temperature in the acceleration of the electrochemical reactions, which are thermoactivated processes. In the context of searching alternative polymeric electrolytes, PBI (polybenzimidazole) membranes have been considered a promising membrane for high temperature operating PEMFC (HT-PEMFC) due to the combination of satisfactory proton conduction in conditions of low relative humidity (RH) and excellent thermal stability. Pure PBI membranes were prepared by casting a solution of PBI / N, N'-dimethylacetamide (DMAc) and doped with phosphoric acid at different times (1, 3, 5, 7 10 and 15 days). Each membrane was evaluated in Fuel Cell tests, doping level and online Raman tests in order to determine effects of doping level, chemical degradation and fuel cell performance. The electrodes were optimized by studying different catalytic layer composition and the cell tested at different operational conditions.