JOAO COUTINHO FERREIRA
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Artigo IPEN-doc 30849 Development of hydrophobic graphenoid layer on Portland cement for non-thermal plasma method2024 - PEREIRA FILHO, N.G.; SOARES, E.P.; FERREIRA, J.C.; SOUZA, R.F.B. de; ANDRADE, D.A.; NETO, A.O.This study focuses on the development of hydrophobic layer on Portland cement using graphenoid materials to enhance impermeability and hydrophobicity. X-ray diffraction analysis indicated that characteristic peaks associated with concrete, such as ettringite, calcium hydroxide, and calcite, remained intact. The application of graphenoid material produced by non-thermal plasma resulted in the formation of carbonaceous structures, minimally affecting the overall cement structure. Raman spectroscopy provided detailed insights into the composition, highlighting the presence of specific and indicating boundary defects. Moreover, contact angle measurements confirmed a substantial increase in hydrophobicity for the graphene-coated cement, with an average angle of 117° ± 4.72° demonstrated graphenoid material layers deposited over structural defects, effectively waterproofing and enhancing local hydrophobicity.Artigo IPEN-doc 29694 Effective phosphate removal from water by electrochemically mediated precipitation with coffee grounds biocarbon obtained by non-thermal plasma method2023 - 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. deThis 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.