SONIA REGINA HOMEM DE MELLO CASTANHO

SONIA REGINA HOMEM DE MELLO CASTANHO

(Fonte: Lattes)

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Graduada em Engenharia de Materiais (UFSCar, Universidade Federal de São Carlos), Mestre em Tecnologia Nuclear (IPEN/USP, Universidade de São Paulo) e Doutora em Ciências Químicas-Cerâmicos (UAM/ES -ICV/CSIC, Universidad Autónoma de Madrid, Espanha e Instituto de Ceramica y Vidrio/CSIC de Espanha). Ela é Pesquisadora Senior e atualmente Gestora Adjunta em Pesquisa e Desenvolvimento do Centro de Ciências e Tecnologia de Materiais (CCTM) do Instituto de Pesquisas Energéticas e Nucleares (IPEN/CNEN-SP). É Professora da Universidade de São Paulo (USP), no programa de posgraduação Tecnologia Nuclear - Materiais. Coordenadora do grupo de pesquisas (GP/CNPq) em Materiais e Meio Ambiente. Principais áreas de atuação: - Energias Renováveis (células a combustível, catalizadores e biomassa), - Ambiental (mitigação, inertização e requalificação de efluentes e subprodutos de processos extrativistas e industriais, diretivas ambientais (RhOS, WEEE)), - Cerâmicas Biocompatíveis (vidros, compósitos multifuncionais para a implantologia). Experiência em gestão de Centro de Pesquisas, gestão ambiental, gestão de projetos, planejamento composicional de materiais, processamento coloidal, reologia, vidros e vitroceramicos, compósitos multifuncionais e nanoestruturas naturais. (Texto extraído do Currículo Lattes em 27 dez. 2021)

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Influência do nióbio na estrutura de vidros borossilicatos para uso nuclear
2022 - MELLO-CASTANHO, S.; SILVA E COSTA, D.L.; FUNGARO, D.A.; VICENTE, R.; BORTOLOME, J.F.
A imobilização de rejeitos radioativos em vidros é uma técnica utilizada em muitos países que possuem programas de energia nuclear, constituindo uma importante rota de tratamento dos rejeitos radioativos de alta atividade, resultantes do reprocessamento do combustível nuclear. Este trabalho estuda a utilização de uma matriz vítrea com a adição de óxido de nióbio para a aplicação futura em imobilização de rejeitos radioativos de média e alta atividade. O estudo foi conduzido a partir de formulações de composições contendo teores de até 8,0 % em mol de Nb2O5 no sistema SiO2-Na2O-CaOB2O3-Al2O3. A funcionalidade do nióbio na estrutura de rede foi avaliada por meio de técnicas espectrométricas, de ensaios de irradiação ? e ? e de resistência hidrolítica, os quais forneceram informações importantes sobre a atuação do óxido na estrutura vítrea. Os resultados obtidos demonstram que a composição selecionada apresenta as especificações adequadas para incorporar e imobilizar elementos de radionuclídeos em sua estrutura de rede em nível atômico. Estas considerações foram obtidas utilizando-se as técnicas: espectroscopia vibratória no infravermelho por transformada de Fourier (FTIR), espectroscopia por ressonância magnética nuclear com rotação em ângulo mágico (MAS-RMN), análise térmica diferencial (ATD), irradiação por fontes de 241Am e por acelerador de feixe de elétrons (60Co) e ensaios de resistência hidrolítica. Os materiais vítreos obtidos são perfeitamente compatíveis com a aplicação proposta de imobilização de rejeitos radioativos por possuírem:superior estabilidade à radiação nuclear e notável resistência química. As pesquisas aqui desenvolvidas tiveram o apoio da Fundação de Amparo à Pesquisa do Estado de São Paulo, projeto n. 2018/10114-7.
Structural and thermal influence of niobia in aluminoborosilicate glasses
2022 - COSTA-SILVA, D.L.; BARTOLOME, J.F.; SILVA, A.C.; MELLO-CASTANHO, S.
The addition of small amounts of niobia (Nb2O5) in borosilicate glasses was explored. By analysis on thermal and structural changes, we found evidences that niobium integrates the glass structure in octahedral NbO6 coordination. Adding up to 8.0 mol% of Nb2O5, the oxide partially ruptured the glass structure, interfering in the BO3/ BO4 ratio, but the predominant network configuration was maintained. Thermally, there was an increase in the processing interval and the glasses became more resistant against crystallization, with the presence of niobia. Also, the oxide contributed to a notable decrease in the viscosity of the melts. The improvement of such properties were obtained by the controlled dispersion of the oxide in the glass network structure, avoiding large areas of phase-to-phase separation to preserve the desired ability of these glasses to incorporate a wide range of elements.
Síntese de pós biocerâmicos dos sistemas CaO-MgO-SiO2 e SiO2-ZrO2 por sol-gel e coprecipitação
2021 - RODRIGUES, VANESSA G.; ERETIDES, GABRIEL T.; RODAS, ANDREA C.D.; CASTANHO, SONIA R.H.M.; YAMAGATA, CHIEKO
Neste trabalho, foram sintetizados pós biocerâmicos dos sistemas CaO-MgO-SiO2 e SiO2-ZrO2 pela combinação das técnicas sol-gel e coprecipitação. Solução Na2SiO3, um efluente de alta pureza gerado no processo de fusão alcalina da zirconita, foi empregada como fonte de SiO2, e soluções clorídricas de Mg e Cl foram utilizadas como precursoras de CaO e MgO. O pó sintetizado de composição molar 43,30% CaO, 10,72% MgO e 45,98% SiO2 apresentou as fases cristalinas wollastonita e diopsita após tratamento térmico a 550 °C por 4h. Cerâmica obtida desta mesma amostra sinterizada a 1200 °C por 2h apresentou bioatividade a partir de 7 dias de imersão em Simulated Body Fluid (SBF) e teste de citotoxicidade mostrou que a amostra não é citotóxica. Para a síntese de pó cerâmico do sistema SiO2-ZrO2 foram utilizadas soluções Na2SiO3 e ZrOCl2 provenientes do processo da fusão alcalina da zirconita como fontes de SiO2 e ZrO2. O pó sintetizado de composição molar (SiO2:ZrO2) (62:38) foi calcinado a 900°C por 3h e a fase tetragonal foi obtida. Cerâmica obtida após sinterização a 1500 °C por 2h foi submetida a teste de bioatividade e citotoxicidade. O produto não apresentou citotoxicidade e até 21 dias de imersão em SBF não apresentou bioatividade.
In vitro bioactivity and antibacterial capacity of 45S5 Bioglass®-based compositions containing alumina and strontium
2021 - ARAUJO, M.S.; SILVA, A.C.; CABAL, B.; BARTOLOME, J.F.; MELLO-CASTANHO, S.
A modified 45S5 Bioglass® containing 2 mol% alumina and 2 mol% strontium oxide was prepared. In vitro bioactivity in powder and monolithic samples was conducted. Fourier transform infrared analysis and pH change in simulated body fluid were investigated for powder samples after 480 min of immersion. Additionally, X-ray diffraction and scanning electron microscopy after 7 and 14 days of immersion in simulated body fluid were investigated for monolithic samples. The formation of phosphate and carbonate phase precursors of hydroxycarbonate apatite was observed after 480 min for powder samples, and the hydroxycarbonate apatite pattern and morphology were confirmed after 7 days of immersion for monolithic samples. It seems that changes in composition did not affect reactivity but caused a decrease in the maxima of pH. Cytotoxicity and cell viability obtained by using the NCTC clone 929 cell line did not show any significant loss of cell viability or cytotoxicity. Moreover, after overnight incubation, the samples demonstrated safe disinfection for Escherichia coli. For these reasons, the use of these new bioactive glasses can be considered a promising alternative for the reconstruction of bone defects and even for the treatment and suppression of bone infections.
Mechanical and nuclear properties of soda-lime glasses containing boron and niobia
2021 - SILVA, DANILO C.; CASTANHO, SONIA M.; VICENTE, ROBERTO
Tribological and mechanical behaviour of 45S5 Bioglass®-based compositions containing alumina and strontium
2020 - ARAUJO, M.S.; BARTOLOMÉ, J.F.; MELLO-CASTANHO, S.
Although bioactive glasses have been widely used for the surfaces of orthopaedic and dental implants, its limited mechanical strength, low toughness and wear resistance have prevented their use as load-bearing devices. Considering that even a small variation in the composition of such materials can deeply modify their features, inducing very different physicochemical or mechanical properties, the present research was conducted by modifying the glass network of 45S5 Bioglass® by adding Al2O3 and SrO to obtain a highly bioactive glass with improved mechanical and tribological performance for biomedical applications. The addition of 2% Al2O3 and 2% SrO produced a dense material with the same elastic modulus as 45S5 (~50 GPa). Moreover, the bending strength increased by 60% and the toughness doubled. The wear rate obtained against steel was found to be three times lower than that of 45S5. From the results, it can be assumed that both alumina and strontium synergistically play crucial roles in the mechanical and tribological properties of these new bioactive glasses.
Structural and thermal behavior of 45S5 Bioglass®-based compositions containing alumina and strontium
2020 - ARAUJO, MARIANA S.; SILVA, ANTONIO C.; BARTOLOMÉ, JOSÉ F.; MELLO-CASTANHO, SONIA
The present research exposes the influence of 2 mol% of Al2O3 and 2 mol% SrO in 45S5 Bioglass®-based compositions. Four compositions were produced to elucidate the difference in how both oxides influence structure and thermal behavior separately and their synergy when together. Thermal properties, crystallization tendency, and sintering behavior was evaluated by differential scanning calorimetry, hot stage microscopy, and dilatometry. Changes of medium-range structures were characterized by Qn distribution of Raman spectroscopy and evaluation of 31P, 27Al, 23Na, and 29Si environment obtained by magic angle spinning nuclear magnetic resonance. Despite Qn distribution was predominantly Q2 in all samples, the composition criteria used enabled improved processing and stabilibity characteristics. The addition of Al2O3 and SrO promoted larger sinterability parameter (Sc) which indicates better sintering behavior, the glass stability against crystallization doubled (KH) compared to 45S5 and the processing window enlarged from 106 to 171.
Niobium modified glass for nuclear waste immobilization
2019 - SILVA, D.L.C. e; SILVA, A.C.; RAMBO, C.R.; CASTANHO, S.
The impact of Nb2O5 addition to glasses belonging to the system SiO2-Na2O-CaO-B2O5-Al2O3 were investigated for nuclear waste immobilization applications. The glass samples, produced by the traditional melting method, were characterized by XRD, Differential Thermal Analysis (DTA) and Fourier-Transform Infrared Spectroscopy (FT-IR). The XRD results confirmed the amorphous state of the glasses and the thermal and FT-IR analyses revealed that Nb2O5 was dispersedly incorporated to the glass structure and that higher contents of the oxide result in a niobate network growth. The glasses showed good resistance to devitrification and are applicable for nuclear waste vitrification processes. These results show that the process is a promising alternative to produce a new family of glasses with optimized thermal resistance for the immobilization of nuclear wastes.
Use of waste water glass as silica supplier in synthesis of pure and Mg-doped lanthanum silicate powders for IT-SOFC application
2019 - YAMAGATA, C.; LEME, D.R.; CASTANHO, S.R.H.M.
Water glass in alkali solution (Na2SiO3/NaOH) an abundant effluent, generated in the alkaline fusion of zircon sand, represents a potential silica source to be converted in useful silica technological application. Actually, the generation of energy by environmental-friendly method is one of the major challenges for researchers. Solid Oxide Fuel Cells (SOFC) is efficient and environmentally clean technique to energy production, since it converts chemical energy into electrical power, directly. Apatite-type lanthanum silicates are promising materials for application as an electrolyte in intermediate temperature SOFC (IT-SOFC) because of their higher ionic conductivity, in temperatures of range 600–700 °C, than conventional zirconia electrolytes. In this work, pure (La9,56(SiO4)6O2,34) and Mg-doped (La9,8Si5,7Mg0,3O26,4) lanthanum silicate were synthesized, from that rich effluent. Using the sol-gel followed by precipitation method, the single crystalline apatite phase of both silicates was obtained by thermal treatment at 900 °C of their precursors. Sintered ceramic samples reached density of higher than 90%.
Low-temperature densification of ceramics and cermets by the intermediary stage activated sintering method
2018 - RESTIVO, THOMAZ A.G.; DURAZZO, MICHELANGELO; MELLO-CASTANHO, SONIA R.H. de; MOREIRA, ANA C.; GRACIANO, SERGIO; TELLES, VICTOR B.; TENORIO, JORGE A.S.
The article explores new concepts in order to promote ceramic and cermet materials sintering at lower temperatures between 1200 and 1300 C. The principle of the new process method called intermediary stage activated sintering (ISAS) involves the preparation of the ceramic powder with dispersed doping agents, such as nanotubes and fibers, which shape the pore structure at pressed pellets with stable interconnected thin cylinders between the grains. This feature resembles and extends the condition found during the intermediary stage sintering, which enhances the ions diffusion rate along tubular pores to increase shrinkage. Carbon nanotubes (CNT) and nanofibers are homogenized into cubic zirconia and alumina in amounts ranging from 1 to 10 vol% at high-energy milling devices and ultrasound disruptor under ethanol media. Ni, Cu and Mo/MoO3 can be also added to provide tubular channel filling. Sintering of uniaxially pressed pellets is carried out in a dilatometer and tubular furnaces at 1200/1300 C under air, argon and controlled oxygen partial pressure atmospheres. TG/DTA/MS analyses of sample pellets reveal the oxidation and gas release temperature and duration. The results demonstrate the ISAS process concept is valid since it further increases the ceramic final density by 8% of the theoretical density at 1200 C, leading to close the porosity at 1300 C, compared to 1500–1600 C temperatures at conventional process. Short CNT and cellulose nanofiber were found to be the best additives in this sense.