JOAO COUTINHO FERREIRA

JOAO COUTINHO FERREIRA

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Synthesis of dibenzo-15-crown-5 - DMSO resin – silica used for isotopic separation of the lithium
2024 - FERREIRA, J.C.; BERGAMASCHI, V.S.; OTOMO, J.I.; SOUZA, R.F. de; SANTOS, D.G.; MORAES, T.S.; VEGA, J.B.
The development of new materials and ligands based on crown ethers capable of mono- and binuclear coordination compounds, free or linked to silica matrices, has been studied by several authors for the isotopic separation of lithium 6/lithium 7. The present work shows the synthesis of dibenzo-15-crown-5 in high-purity silica gel polymeric material, pore size 60 Å, 70–230 mesh. B15C5 was dissolved in a mixture of 15 g of phenol in 250 mL of methanol and 100 mL of DMSO in a reaction vessel, and approximately 50 g of porous silica granules were added to the solution, which was stirred for approximately 10 minutes by a rotoevaporator shaker under reduced pressure at room temperature. After the evaporation of methanol, approximately 10 g of formalin, 70 mL of formic acid, and 1 mL of sulfuric acid were added to the reaction flask and left to form the polymerization for 24 h under reduced pressure at 70?C. The pressure decreased further near the boiling point of the reactant solution by removing the reactant solution. The silica resins with a yellowish color were washed with water repeatedly until the neutral pH of the washing water was reached. The characterization of the dry resin spheres under reduced pressure was carried out via thermogravimetric analysis, infrared and ultraviolet spectroscopy, and nuclear magnetic resonance to verify the presence of carbon and hydrogen. The prepared material was placed in a chromatographic column positioned in series, forming stages, in the form of a cascade, for isotopic separation of the 99.98% purity lithium solution. Isotopic separation using the prepared material was evaluated by a quadrupole mass spectrometer.
Nickel, ceria and niobium catalysts are supported on alumina in the steam reforming of ethanol to obtain hydrogen
2024 - FERREIRA, J.C.; BERGAMASCHI, V.S.; SILVA, E.M.; SOUZA, R.F. de; MORAES, T.S.
Heterogeneous catalysts of nickel, niobium and cerium supported on alumina were prepared by the co-precipitation method in different chemical compositions. After the synthesis of the catalysts, the samples were calcined at 800 °C for 4 hours in a muffle furnace. Then, the obtained samples were analyzed by different characterization methods, such as X-ray Diffraction (XRD), X-ray Dispersive Spectrometry (EDS), Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), Programmed Temperature Reduction (TPR), and Thermogravimetric Analysis (TG). The characterized catalysts were evaluated in catalytic tests using steam reforming of ethanol to produce hydrogen. A quartz fixed-bed catalytic reactor with an internal diameter of 6 mm was used. The catalytic reactor was filled with 100 mg of catalyst, and then the catalyst was activated using a hydrogen flow of 30 mL.min-1. After activating the catalyst, ethanol was steam reformed under the following operating conditions. Water/ethanol molar ratio equal to 3:1, Reaction temperature of 600 °C. The synthesis gases obtained in the reaction, such as hydrogen, carbon monoxide, carbon dioxide and methane, were analyzed in a gas chromatograph, coupled online to the catalytic reactor. The chromatograph used is equipped with two detectors, a thermal conductivity detector (TCD) and another for ionic conductivity (FID), in addition to two gas separation columns, a molecular column serving 5 A and another Porapak column.
Development of hydrophobic graphenoid layer on Portland cement for non-thermal plasma method
2024 - 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.
Purification of lithium ions from lithium hydroxide solution by ion exchange method using cationic resin AG 50W-X8 e HPR 1200
2024 - FERREIRA, JOAO C.; SANTOS, DANIELA da C.G.; OTOMO, JULIANA I.; BERGAMASCHI, VANDERLEI S.; BUSTILLOS, JOSE O.V.
Separation techniques of lithium isotopes by ion exchange method and monitoring by ICP-MS
2024 - BUSTILLOS, J.O.V.; OTOMO, J.I.; LEAO, P.H.B.; ROVELO, B.S.; SANTOS, D.C.G.; FERREIRA, J.C.; BERGAMASCHI, V.; ALVARENGA, V.
Comparison of ion exchange methods for lithium-7 isotopic enrichment for application in PWR reactors
2024 - OTOMO, JULIANA I.; SANTOS, DANIELA da C.G.; COUTINHO, JOAO F.; BERGAMASCHI, VANDERLEI S.; BUSTILLOS, JOSE O.W.V.
Calcium determination by permanganometry and EDTA complexation
2024 - SANTOS, DANIELA da C.G.; NASCIMENTO, LETICIA da S.; BUSTILLOS, JOSE O.W.V.; COUTINHO, JOAO F.; BERGAMASCHI, VANDERLEI S.; OTOMO, JULIANA I.
Graphene deposited on glass fiber using a non-thermal plasma system
2023 - GOMES, PAULO V.R.; BONIFACIO, RAFAEL N.; SILVA, BARBARA P.G.; FERREIRA, JOAO C.; SOUZA, RODRIGO F.B. de; OTUBO, LARISSA; LAZAR, DOLORES R.R.; NETO, ALMIR O.
This study reports a bottom-up approach for the conversion of cyclohexane into graphene nanoflakes, which were then deposited onto fiberglass using a non-thermal generator. The composite was characterized using transmission electron microscopy, which revealed the formation of stacked few-layer graphene with a partially disordered structure and a d-spacing of 0.358 nm between the layers. X-ray diffraction confirmed the observations from the TEM images. SEM images showed the agglomeration of carbonaceous material onto the fiberglass, which experienced some delamination due to the synthesis method. Raman spectroscopy indicated that the obtained graphene exhibited a predominance of defects in its structure. Additionally, atomic force microscopy (AFM) analyses revealed the formation of graphene layers with varying levels of porosity.
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.
Optimizations on Lithium ion exchange separation and isotopic measurements
2022 - OTOMO, JULIANA I.; GIMENEZ, MAISE P.; ANDRADE, MARIANA N. de; MONTEIRO, LUCILENA R.; NASCIMENTO, LETICIA da S.; BATAGLIA, HENRIQUE; LEAO, PAULO H.B.; CECILIO, PRISCILA de S.; BERGAMASCHI, VANDERLEI; COUTINHO, JOAO F.; BUSTILLOS, JOSE O.W.V.
Introduction: The Lithium-7 is of interest for nuclear application, being used for primary cooling of PWR (Pressurized Water Reactor) reactors [1]. An environmentally friendly technique is required to replace the Mercury amalgam technique used worldwide [1,2]. This work aims to present the preliminary results of the development of 7Li separation by ion exchange. Methods: A 120 mm x1.0 cm i.d. glass column filled with Dowex 50W-x16 resin was used. A total of 3.0 liters of 0.2 M CH3COOLi solution percolated the column in order to saturate and displace the formed band of 6Li and 7Li. Fractions were collected every 50 mL, then the resin was washed with 5M HNO3 and ultrapure water. The fractions were filtered and evaporated at 80°C, finally taken up with HNO3 1%. Samples were analyzed by ICP-OES – SPECTRO ARCOS. The fractions were analyzed by ICP-MS, model ELAN 6000 – SCIEX. For isotopic ratio measurement, with the parameters of gas flow of approximately 1.1 L min-1, RF 600 W, gas flow rate 1.2 L min-1, Peak Hopping mode, dwell time 80 and 480 for 6Li and 7Li (respectively), 50 sweeps per reading, 1 read per replicate and 10 replicates. Results: A total of 63 samples were collected from the separation experiment. The Li isotopic ratio measured for each fraction was assessed by ANOVA one-way considering the differences among fractions. A statistical significant difference was observed between the fraction 1 and the remainder fractions and the load solution. The remaining fractions showed an isotopic ratio around the natural abundance (6Li/7Li: 7.59%/92.41% = 0.082). The isotopic ratio of this sample indicated enrichment of 7Li of 0.92% in the fraction number 30. Conclusions: The method of ion exchange with Dowex 50W-x16 resin was efficient on 7Li separation and through ICP-MS method was able to measure the δ 84%₀ enrichment of the 7Li. The isotopic separation procedure via ion exchange is still being studied, however the results are promising.