Mariana S. Araujo

Mariana S. Araujo


Research Focus & Metrics

Academic Career Length

10Years (2017-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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12 February 2020 in Journal of the American Ceramic Society
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Journal Article
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MAMariana S. Araujo
Mariana S. Araujo
ASAntonio C. Silva
Antonio C. Silva
Jose F. BartolomeJose F. Bartolome
Jose F. Bartolome
SMSonia Regina Mello-castanho
Sonia Regina Mello-castanho

1 January 2020 in Journal of Luminescence
Verified
Journal Article
Closed access
DSDiego Silvério Da Silva
Diego Silvério Da Silva
NWNiklaus Wetter
Niklaus Wetter
Luciana Reyes Pires KassabLuciana Reyes Pires Kassab
Luciana Reyes Pires Kassab
WRWagner De Rossi
Wagner De Rossi
MAMariana S. Araujo
Mariana S. Araujo

31 December 2024 in Chemistry
Verified
Journal Article
Open access
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MAMariana S. Araujo
Mariana S. Araujo
DSDanilo Silva
Danilo Silva
JIJuliana C. Izidoro
Juliana C. Izidoro
DFDenise Alves Fungaro
Denise Alves Fungaro
SMSonia Regina Mello-castanho
Sonia Regina Mello-castanho
The present investigation explores the potential of two synthesized zeolites, derived from coal fly ash (CFA; thermoelectric waste) and sugarcane bagasse ash (SCBA; agro-industrial waste), for the selective adsorption of cesium in wastewater. The synthesized zeolites (ZCFA and ZSCBA) were characterized and compared with a commercial zeolite to evaluate their physicochemical properties and effectiveness in removing cesium ions (Cs+) from simulated radioactive wastewater. The results obtained from X-ray diffraction, scanning electron microscopy, and elemental analysis confirmed the successful synthesis of high-purity zeolite from both solid wastes. The impurities present in the ashes impacted the Si/Al ratio and consequently influenced the exchange capacity. After adsorption experiments, neutron activation analysis (NAA) revealed that ZSCBA adsorbed 33.4% of Cs2O by weight, outperforming both ZCFA (26.0%) and commercial zeolite (27.9%). The superior performance of ZSCBA is attributed to its distinct Si/Al ratio and lower levels of impurities, highlighting the impact of these factors on adsorption selectivity. The findings in this study demonstrate the feasibility of valorizing agro-industrial waste for synthesizing zeolites, offering a sustainable approach for managing these residues while producing valuable materials for environmental remediation.

11 December 2024 in Brazilian Journal of Radiation Sciences
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Journal Article
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HAHilda Pereselevicius Antonietto
Hilda Pereselevicius Antonietto
MOMaria José Alves de Oliveira
Maria José Alves de Oliveira
MAMariana S. Araujo
Mariana S. Araujo
LOLarissa Otubo
Larissa Otubo
SMSonia Regina Mello-castanho
Sonia Regina Mello-castanho
PVPablo Vasquez
Pablo Vasquez
Ionizing radiation is an alternative in combating the deterioration of cultural heritage as it is effective in eliminating biological infestations, from the presence of insects to contamination by fungi and bacteria. The process took place through the emission of gamma radiation (60 Co). The objects of study refer to 3 samples of canvas that received layers of paints and pigments, both intended for the practice of restoring works of art and that were exposed to cumulative doses of 3 to 15 kGy. Instrumental analyzes included X-ray Fluorescence Spectroscopy – XRF, Colorimetry, Scanning Electron Microscopy - SEM and Fourier Transform Infrared Spectroscopy - FTIR. The results of the analyzes showed that the samples remained without significant changes.

28 March 2025 in Radiation Physics and Chemistry
Verified
Journal Article
Closed access
MOMaria José Alves de Oliveira
Maria José Alves de Oliveira
MAMariana S. Araujo
Mariana S. Araujo
LOLarissa Otubo
Larissa Otubo
SMSonia Mello-Castanho
Sonia Mello-Castanho
PVPablo Vasquez
Pablo Vasquez

11 December 2024 in Brazilian Journal of Radiation Sciences
Verified
Journal Article
Open access
DSDanilo Lopes Costa e Silva
Danilo Lopes Costa e Silva
MAMariana S. Araujo
Mariana S. Araujo
DFDenise Alves Fungaro
Denise Alves Fungaro
SMSonia Regina Mello-castanho
Sonia Regina Mello-castanho
Nuclear power generation has been increasing worldwide over the years, helping to avoid the emission of billions of tons of carbon dioxide (CO2) compared to coal power generation, making it a reliable method for providing green energy. However, as a byproduct of nuclear reactors, as well as fuel processing plants, hospitals, and research institutes, radioactive waste is generated. These wastes pose a significant risk to human health and the environment due to the penetration of radioactivity into tissues, which damages DNA. Therefore, they need to be managed appropriately before long-term disposal in geological repositories. Among the many radionuclides found in high-activity waste, 137Cs is of particular concern due to its high mobility in water systems, requiring special methods for its capture and immobilization in stable matrices. In this study, the immobilization of 137Cs radionuclides in a borosilicate glass doped with niobium (Nb) was thermally evaluated through a vitrification process, using a synthetic type A zeolite saturated with 133Cs (stable) as a simulated radioactive waste. The incorporation of 40.0 wt.% of this material into the glass composition resulted in a vitrified waste with good melting homogeneity and thermal stability. Several changes due to the incorporation were detected in thermal analysis (DTA), with events such as glass transition, initial crystallization, complete crystallization, and subsequent melting all shifting to higher temperatures. The compositional changes induced by vitrification moved the system to new locations in the ternary equilibrium phase diagrams of the subsystems, in different compatibility triangles, and closer to higher liquidus temperatures than those observed for the raw glass matrix. Through crystallization induced by heat treatment, crystalline phases were obtained, as indicated in the phase diagrams. Cs atoms previously immobilized in the glass network structure became components of pollucite crystals (CsAlSi₂O₆) during heating up to 800 ºC. These results are promising for using this glass composition to immobilize waste containing 137Cs, as Cs atoms showed excellent interaction with this system in both the glass and crystalline phases.