SABINE NEUSATZ GUILHEN

SABINE NEUSATZ GUILHEN

(Fonte: Lattes)

Resumo

Possui graduação em Química com atribuições Tecnológicas e Biotecnológicas pelo Instituto de Química da Universidade de São Paulo (2005), mestrado (2009) e doutorado (2018) em Tecnologia Nuclear (Materiais) pelo Instituto de Pesquisas Energéticas e Nucleares (IPEN), Universidade de São Paulo. Tem experiência em Química Analítica com ênfase em Análise de Traços, atuando principalmente no desenvolvimento de métodos analíticos empregando técnicas espectrofotométricas (AAS, ICP OES e ICP-MS) para caracterização de amostras ambientais, arqueológicas, biológicas, forenses e nucleares. Atualmente, ocupa o cargo de Tecnologista em "Caracterização Química" no Centro de Química e Meio Ambiente (CQMA) do IPEN (CNEN/SP), onde desempenha atividades de pesquisa e desenvolvimento tecnológico em atendimento às demandas institucionais ligadas ao Ciclo do Combustível Nuclear e aos Programas de Pesquisa de caráter multidisciplinar, em apoio a projetos de Inovação Tecnológica e ao Programa de Pós-Graduação do IPEN/USP. Além disso, atua na geração de produtos tecnológicos e no desenvolvimento de materiais adsorventes de baixo custo e alto valor agregado visando o aproveitamento de materiais e resíduos naturais e/ou renováveis no tratamento de efluentes e rejeitos. (Texto extraído do Currículo Lattes em 4 maio 2023)

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Agora exibindo 1 - 10 de 22

Biossorção de radionuclídeos em solução aquosa
2023 - ALEXANDRE, KAILAINE A.S.; GUILHEN, SABINE N.
X-ray fluorescence spectrometry
2023 - SCAPIN, M.A.; TESSARI-ZAMPIERIA, M.C.; GUILHENA, S.N.; COTRIM, M.E.B.
This study aims to develop reliable analytical methodology that is, cost-effective, and requires minimal sample quantity to quantify uranium content in nuclear waste and others. The Energy Dispersive X-ray Fluorescence Spectrometry (EDXRF) technique was used, and a rigorous comparison was made between the fundamental parameters (FP) method and the empirical (EMP) method. Statistical evaluation of results demonstrated that the FP method showed a satisfactory level of confidence for precision and limit of quantification.
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.
Methylene blue biosorption by bone meal using experimental design
2022 - ARAUJO, LEANDRO G. de; CAMPERA, ALEXSSANDRA A.A.; MARUMO, JULIO T.; GUILHEN, SABINE N.
This study aims at expanding the knowledge on the applicability of bone meal powder (BMP), and assess its potential as an adsorbent material for methylene blue (MB) removal, a toxic textile dye. BMP is a low-cost material still little studied for the adsorption of contaminants in aqueous media. In this work, we employed the 2k experimental design (k = 3) to systematically explore the most important process parameters, which were pH of the MB solution, initial MB concentration in solution and biosorbent dosage (mass of biosorbent/volume of contaminated solutions).
Anionic dye removal from aqueous solutions using standard biochars
2022 - GUILHEN, SABINE N.; MARTINS, GABRIEL F.; MARUMO, JULIO T.; ARAUJO, LEANDRO G. de
One of the most serious problems related to water pollution by the textile, plastics, leather and food industries, among others, is the emission of aqueous effluents containing dyes. The most commercially used dyes are resistant to biodegradation, photodegradation and the action of oxidizing agents. The presence of dyes in water bodies can significantly and adversely affect the photosynthesis of aquatic plants by reducing the penetration of sunlight. In addition, they can be toxic to certain forms of aquatic life. Treatment of aqueous effluents containing dyes can involve a variety of materials and techniques, of which adsorption stands out for its simplicity, low cost and efficiency. In this study, standard biochars derived from wheat straw (WSP), oil seed rape straw (OSR) and Miscanthus straw (MSP), obtained at two different pyrolytic temperatures (550 °C and 700 °C), were investigated as adsorptive materials for remazol black (RB) dye. Maximum adsorption capacities were obtained at a dosage of 5 g L-1 for most of the BCs, except for MSP550, for which the dosage of 10 g L-1 achieved the highest performance. pH effect indicated that most of the adsorptive functionalities of the BCs are favored at pH 5. The steps currently in progress refer to the experimental design for the optimization of adsorption parameters and will be added in the full paper.
Uso de biocarvão para a captação dos nutrientes P e N de estações de tratamento de esgoto visando mitigar o processo de eutrofização de reservatórios de águas
2022 - SILVESTRIN, GABRIEL de A.; GUILHEN, SABINE N.
Uranium biosorption by hydroxyapatite and bone meal
2021 - WATANABE, TAMIRES; GUILHEN, SABINE N.; MARUMO, JULIO T.; ARAUJO, LEANDRO G. de
Biosorption has been widely examined for the treatment of aqueous solutions containing uranium, a radiotoxic pollutant. The use of hydroxyapatite and bone meal as potential biosorbents in the removal of uranium (U) from aqueous solutions has not yet been previously addressed. In this work, the efficiency of these biosorbents in the removal of U was investigated according to their adsorption removal capacities. Surface transformations in both materials were observed after U adsorption by scanning electron microscopy combined with energy-dispersive X-ray spectroscopy (SEM/EDS). The biomass/U solution ratio was kept at 0.1 g/5 mL. Contact times for the batch experiments were 15, 30, 60, 120, and 180 min, and the concentration of U tested was 680 mg L-1. The equilibrium was achieved in less than 15 min for both materials. The morphological characteristics of each biomass, before and after biosorption experiments were analyzed. Bone meal highlighted slightly superior adsorption results in terms of maximum capacity (qmax = 33.83 mg g-1), compared to hydroxyapatite (qmax = 33.36 mg g-1), with the removal percentages being also similar, 99.97 and 98.57 %, respectively. The results so far indicate that these materials are potential biosorbents for the treatment of uranium-contaminated solutions, especially liquid radioactive waste.
Brazilian clays for environmental solutions applied to radioactive waste management
2021 - MACHADO, G.G.; KRUPSKAYA, V.V.; ZAKUSIN, S.V.; HARADA, J.; VICENTE, R.; SOUZA, R.P.; ARAUJO, L.G.; MONTALVAN, E.T.; ESPINOSA, D.C.R.; KAHN, H.; GUILHEN, S.N.
Clayey materials have been adopted in most nuclear waste producing countries as a key constituent in engineered barrier systems for final disposal facilities at all levels of radioactive wastes (LILW-SL, LILW-LL, and HLW). The following study presents a thorough characterization upon five Brazilian clay-rich deposits, mostly smectite bearing clays, aiming to evaluate their expected performance as barrier under the conditions associated to a Low and Intermediate Level Waste Repository; being the former a matter of national strategic interest. Samples coming from the Brazilian states of Paraná, Bahia, Paraíba, and Maranhão were treated and analyzed by means of X-Ray diffraction as main technique. Other techniques such as FTIR, LALLS, XRF, and SEM-EDS, were performed in order to establish the mineralogical composition, particle size distribution, and chemical composition. Moreover, several standard clay treatments over the <1 μm size fraction were carried out to reveal information regarding layer charge, major interlayer cations, unit formula and other crystal features of smectite species present in a mineralogical assembly, aiming to provide information for the construction of a molecular model over which would be realistic to simulate the diffusion of radionuclides. Results obtained on 133Cs adsorption experiments indicate that mineralogical composition would probably be the single most influential factor controlling transport capacity of positively charged radionuclides in the current setup. The composition is especially expressed in terms of smectite contents, favoring montmorillonite rich materials containing majorly Na+ as compensating cation in interlayer position. All tested samples can be considered as suitable candidates to be used in the design of final destination storage for nuclear waste. Thus, efficiency on 133Cs adsorption trials also indicate that these materials could have potential uses as sorptive matrices (Sorbents) for water treatment of radionuclide polluted waters such as TENORM waste waters. However, these trends are yet to be contrasted against hydraulic conductivity measurements and swelling pressure in order to have a more comprehensive perspective of this clayey prospects as barrier enhanced layer; aligned to the multilayer barrier system approach for nuclear waste management.
Direct determination of aluminum in low-enriched UAlx targets (UAlx-Al) by ICP OES
2021 - GUILHEN, S.N.; SOUZA, A.L.; COTRIM, M.E.B.; PIRES, M.A.F.
The production of molybdenum-99 (99Mo) using low-enriched uranium targets (< 20% 235U) dispersed in aluminum (UAlx) is a very promising strategy towards the independence in 99Mo local production. A thorough control must be performed to ensure that these targets meet the regulatory requirements to achieve the expected efficiency in the reactor. The determination of the targets’ composition is of high interest, because the distribution of Al in different phases may have an impact on the U concentration. Among the techniques used for this purpose, inductively coupled plasma optical emission spectrometry (ICP OES) stands out because of its high sensitivity and precision, allowing for simultaneous determination of several elements in a variety of samples and matrices. However, because U exhibits a complex emission spectrum, spectral interferences are prone to affect the analysis of Al, calling for time consuming preparation steps to remove the U from the matrix. This study proposes a method of direct determination of Al in UAlx targets through the selection of specific emission lines enabled by the evaluation of the associated interferences on the recovery values.
Mercury exposure among dental staff in the Legal Amazon
2019 - VILLIBOR, FERNANDA F.; GUILHEN, SABINE N.; DANTAS, ELIZABETH S.K.; PIRES, MARIA A.F.
Elemental mercury is highly toxic and may be absorbed by dental professionals through direct skin contact or inhalation. The use of mercury in dental amalgam has been a concern of the academic community for years, for its incorporation is likely to affect vital organ systems. Several studies have been conducted to address the possible risks of occupational exposure to mercury vapor in dental offices. The present study aimed to present evidences that mercury is assimilated by exposed workers through the determination of urinary mercury (HgU) from dental professionals (n = 91) of public offices in Araguaína (Tocantins, Brazil). This uptake was verified against samples from unexposed individuals (n = 43), which activities are not dentistry related. Cold vapor atomic absorption spectrometry (CV-AAS) technique enabled the subjects’ biological monitoring. Approximately 44.8% (n = 60) of the 134 participants were aged between 21 and 30 years and were at the beginning of their professional lives; 9.7% (13) of the study participants were men and 90.3% (121) were women. Hg concentrations in all samples analyzed were within the maximum biological limit set by the World Health Organization (WHO) (<50 μgHg·L−1). HgU concentrations in dental professionals were within the limits proposed by the Brazilian regulatory standard, Regulatory Norm-7 (RN-7) (≤35 μgHg·g−1 creatinine). Nevertheless, the average concentration of HgU was approximately 8 times higher in the potentially exposed group (5.61 μgHg·g−1 creatinine) than in the unexposed group (0.65 μgHg·g−1 creatinine), highlighting the potential risk of occupational exposure to mercury.