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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New approach to niobia-modified borosilicate glasses for Cs waste immobilization
2024 - COSTA-SILVA, D.L.; ARAUJO, M.S.; FUNGARO, D.A.; SILVA, P.S.C.; MELLO-CASTANHO, S.
The use of nuclear materials is increasing in energy production, medicine, and environmental sectors. Following this trend, the generation of radioactive wastes is also increasing in the whole production cycle and use of this kind of materials. Among these, the 137Cs radionuclide presents a potential risk to human health due to its half-life time (30,2 years), high-level activity (1 TBq) and easiness to contaminate rivers, soil, and air. The immobilization of 137Cs in solid matrices has been an available option researched by several countries. In this context a new glass composition based on aluminoborosilicate glass modified with niobium (Nb) was used for the immobilization of cesium through adding Cs-loaded zeolite. Homogeneous vitreous wasteforms were improved with the growth of Nb content in the compositions. All compositions were able to keep up to 5.9 wt% Cs2O, previously adsorbed by zeolite A, and the immobilization efficiency was around 53%. Their structural analyses by Raman revealed a depolymerized and complex network structure, due to the presence of several cations including Cs. In turn, Nb reflected positively on the chemical resistance and thermal properties, by changing the distribution of silicate species. The wasteforms presented good glass forming ability and thermal stability up to 520 °C. Through the thermal treatment for devitrification, Cs atoms were stabilized into the Pollucite phase (CsAlSi2O6). Besides that, the wasteforms, preferably the one containing 8.0 mol% Nb, showed low elemental releases and leaching rates for Cs (1 × 10−3 g m2.day−1), after the leaching experiments at 90 °C for 7 days in static conditions, verified by the neutron activation analysis (NAA).
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.