Navegação por Autores IPEN "GUILHEN, SABINE N."

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  • IPEN-DOC 29525

    GUILHEN, SABINE N. ; MARTINS, GABRIEL F. ; MARUMO, JULIO T. ; ARAUJO, LEANDRO G. de. Anionic dye removal from aqueous solutions using standard biochars: preliminary study. In: ENCONTRO BRASILEIRO SOBRE ADSORÇÃO, 14., 23-25 de novembro, 2022, Brasília, DF. Anais... Recife, PE: Even3, 2022.

    Abstract: 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.

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  • IPEN-DOC 24071

    SCAPIN, MARCOS A. ; GUILHEN, SABINE N. ; AZEVEDO, LUCIANA C. de ; COTRIM, MARYCEL E.B. ; PIRES, MARIA A.F. . Application of bias correction methods to improve U3Si2 sample preparation for quantitative analysis by WDXRF. In: INTERNATIONAL NUCLEAR ATLANTIC CONFERENCE, October 22-27, 2017, Belo Horizonte, MG. Proceedings... Rio de Janeiro, RJ: Associação Brasileira de Energia Nuclear, 2017.

    Abstract: The determination of silicon (Si), total uranium (U) and impurities in uranium-silicide (U3Si2) samples by wavelength dispersion X-ray fluorescence technique (WDXRF) has been already validated and is currently implemented at IPEN’s X-Ray Fluorescence Laboratory (IPEN-CNEN/SP) in São Paulo, Brazil. Sample preparation requires the use of approximately 3 g of H3BO3 as sample holder and 1.8 g of U3Si2. However, because boron is a neutron absorber, this procedure precludes U3Si2 sample’s recovery, which, in time, considering routinely analysis, may account for significant unusable uranium waste. An estimated average of 15 samples per month are expected to be analyzed by WDXRF, resulting in approx. 320 g of U3Si2 that wouldn’t return to the nuclear fuel cycle. This not only impacts in production losses, but generates another problem: radioactive waste management. The purpose of this paper is to present the mathematical models that may be applied for the correction of systematic errors when H3BO3 sample holder is substituted by cellulose-acetate {[C6H7O2(OH)3-m(OOCCH3)m], m = 0~3}, thus enabling U3Si2 sample’s recovery. The results demonstrate that the adopted mathematical model is statistically satisfactory, allowing the optimization of the procedure.

    Palavras-Chave: acetates; boric acid; boron 10; corrections; errors; impurities; mathematical models; optimization; quantitative chemical analysis; sample preparation; uranium silicides

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  • IPEN-DOC 26406

    GUILHEN, SABINE N. ; COTRIM, MARYCEL E.B. ; SAKATA, SOLANGE K. ; SCAPIN, MARCOS A. . Application of the fundamental parameter method to the assessment of major and trace elements in soil and sediments from Osamu Utsumi uranium mine by WDXRF. REM - International Engineering Journal, v. 72, n. 4, p. 609-617, 2019. DOI: 10.1590/0370-44672018720146

    Abstract: Wavelength dispersive X-ray fluorescence spectrometry (WDXRF) is a suitable technique for the characterization of contaminated mining sites, providing a quick and reliable screening for areas of significant contamination. This study established and validated a non-destructive methodology for quantitative simultaneous determination of major and minor constituents in soil and sediments by WDXRF, which was further applied to quantify soil and sediment samples from Osamu Utsumi uranium mine (Caldas, Minas Gerais, Brazil). Elements such as Ce, La, Nd, Mn and U were found in more concentrated levels in the calcium diuranate deposit (DUCA), whereas Fe and Al were found at higher levels in the soil samples corresponding to sites where accentuated leaching processes have occurred. Comparatively, the levels of U and rare-earth elements were found in significantly higher levels in the sediments retrieved from the mine’s pit as a result of acid mine drainage. These findings are believed to be useful as an initial environmental assessment for the decommissioning process of the mine.

    Palavras-Chave: uranium mines; wavelengths; x-ray fluorescence analysis; x-ray spectroscopy; fluorescence spectroscopy; calculation methods; validation; soils; sediments; brazil; environmental impacts

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  • IPEN-DOC 22467

    SETANI, RENATA Y.; SOUSA, JOSE S. de ; GUILHEN, SABINE N. ; FURUSAWA, HELIO A. ; COTRIM, MARYCEL E.B. ; MACEDO, FERNANDA de M.; RIBEIRO FILHO, WALDEMAR A.. Assessment of efficiency Allium sativum L. used in the bioremediation of metals cadmium (II) and nickel (II) in aqueous solution. In: REUNIÃO ANUAL DA SOCIEDADE BRASILEIRA DE QUIMICA, 39., 30 de maio - 2 de junho, 2016, Goiania. Resumo... 2016.

    Palavras-Chave: allium sativum; sorption; cadmium ions; garlic; nickel ions; efficiency; aqueous solutions; evaluation; adsorbents; spectroscopy

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  • IPEN-DOC 20978

    GUILHEN, SABINE N. ; OLIVEIRA, FERNANDO M. de ; FILHO, WALTER S.; COTRIM, MARYCEL E.B. ; SAKATA, SOLANGE K. ; SCAPIN, MARCOS A. . Assessment of major and trace elements in soil and sediments from Osamu Utsumi uranium mine by WDXRF. In: INTERNATIONAL NUCLEAR ATLANTIC CONFERENCE; MEETING ON NUCLEAR APPLICATIONS, 12th; MEETING ON REACTOR PHYSICS AND THERMAL HYDRAULICS, 19th; MEETING ON NUCLEAR INDUSTRY, 4th, October 4-9, 2015, São Paulo, SP. Proceedings... 2015.

    Palavras-Chave: brazil; elements; soils; sediments; mines; spectroscopy; x-ray fluorescence analysis

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  • IPEN-DOC 23080

    MIRANDA, CAIO da S. ; IZIDORO, JULIANA de C. ; GUILHEN, SABINE N. ; FUNGARO, DENISE A. . Avaliação da remoção de elementos metálicos tóxicos presentes no efluente do aterro de cinzas de carvão mineral usando zeólita sintética. In: CONGRESSO BRASILEIRO DE CARVAO MINERAL, 5., 29 de maio - 01 de junho, 2017, Criciúma, SC. Anais... 2017.

    Abstract: A produção de energia elétrica usando carvão mineral gera diferentes tipos de resíduos que precisam ser dispostos adequadamente para não causar impactos ambientais significativos. Diversas técnicas têm sido adotadas para que haja a redução da lixiviação dos elementos metálicos tóxicos presentes nas cinzas. O preparo do aterro de cinzas usando camadas de calcário e argila foi usado como alternativa por uma usina termelétrica a carvão localizada na região sul do Brasil. A utilização das cinzas leves para a síntese de materiais de valor agregado, por outro lado, também pode amenizar esse problema pelo fato de reduzir a quantidade de resíduo a ser disposto. O objetivo do presente trabalho foi avaliar a remoção de elementos tóxicos presentes no efluente de um aterro de cinzas usando zeólitas sintetizadas a partir dos próprios resíduos de combustão do carvão. Os ensaios foram realizados em batelada empregando-se 10 g de zeólita/L e 20 g de zeólita/L. A comparação entre as concentrações dos elementos do efluente antes e após o contato com a zeólita, bem como as análises de pH e condutividade foram realizadas. Os resultados indicaram que cromo e arsênio foram os principais elementos tóxicos presentes no efluente do aterro de cinzas que apresentavam concentração acima do permitido pela legislação ambiental. Após o tratamento com a zeólita, a concentração de arsênio no efluente reduziu de 1,09 mg/L para 0,275 mg/L na dose de 10 g/L e ficou abaixo do limite de detecção do equipamento (< 0,01) na dose de 20 g/L. Para o cromo, não houve alteração da concentração, enquanto uma elevação dos valores de pH e condutividade do efluente foi observada. O presente estudo sugere que a zeólita de cinzas leves de carvão podem ser usadas como forma de tratamento de efluentes contendo elevados níveis de arsênio.

    Palavras-Chave: coal; ashes; residues; sanitary landfills; waste water; zeolites

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  • IPEN-DOC 29975

    ALEXANDRE, KAILAINE A.S. ; GUILHEN, SABINE N. . Biossorção de radionuclídeos em solução aquosa: uma revisão sistemática. In: PROGRAMA INSTITUCIONAL DE BOLSAS DE INICIAÇÃO CIENTÍFICA; SEMINÁRIO ANUAL PIBIC, 29.; SEMINÁRIO ANUAL PROBIC, 20.; SEMINÁRIO ANUAL PIBITI, 13., 23-24 de novembro, 2023, São Paulo, SP. Resumo expandido... São Paulo, SP: IPEN-CNEN/SP, 2023.

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  • IPEN-DOC 26216

    MACHADO, GABO G.; GUILHEN, SABINE N. ; KRUPSKAYA, VICTORIA V.; ZAKUSIN, SERGEY V.; TYUPINA, EKATERINA A.; HARADA, JULIO; VICENTE, ROBERTO ; SOUZA, RODRIGO P. de; ARAUJO, LEANDRO G. de ; ESPINOSA, DENISE C.R.. Brazilian clays as potential buffer materials for radioactive waste final storage. In: INTERNATIONAL NUCLEAR ATLANTIC CONFERENCE, October 21-25, 2019, Santos, SP. Proceedings... Rio de Janeiro: Associação Brasileira de Energia Nuclear, 2019. p. 1357-1366.

    Abstract: Clayey materials have been adopted in most nuclear waste producing countries, as a key constituent in engineered barrier 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 clay buffer under the conditions associated to a Low and Intermediate Level Waste Repository (RBMN); being the former a matter of national strategic interest. Samples coming from the Brazilian states of Bahia, Maranhão, Pará and Paraíba were treated and analyzed by means of X-Ray diffraction as a main technique, and complemented by FTIR, LALLS, XRF and SEM-EDS, in order to stablish 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, enabling 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, and can be expressed in terms of smectite contents, favoring montmorillonite rich materials containing majorly Na+ as compensating cation in interlayer position. Thus, the obtained data will be useful in the testing of optimal compaction conditions to obtain the most suitable buffer material for the repository design. However, this trend is yet to be contrasted against hydraulic conductivity measurements and swelling pressure to see how they match.

    Palavras-Chave: adsorption; buffers; cesium 133; chemical composition; clays; fourier transformation; infrared spectra; mineralogy; particle size; radioactive waste storage; scanning electron microscopy; x-ray diffraction; x-ray fluorescence analysis

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  • IPEN-DOC 25003

    IZIDORO, JULIANA de C. ; MIRANDA, CAIO da S. ; GUILHEN, SABINE N. ; FUNGARO, DENISE A. . Chemical, mineralogical and environmental characterization of combustion byproducts generated from mineral coal used for electricity production. In: INTERNATIONAL CONFERENCE ON MATERIALS CHEMISTRY, 13th, July 10-13, 2017, Liverpool, UK. Proceedings... Cambridge: Royal Society of Chemistry, 2017. p. 1-14.

    Abstract: The coal combustion by-products, bottom ash (BA), fly ash from cyclone filter (CA) and fly ash from bag filter (FA), generated in a Brazilian thermoelectric power plant, were characterized by Xray fluorescence, X-ray diffractometry and leaching and solubilization tests. The material retention systems used in the Brazilian power plant from where these by-produtcts were sampled are showed in Figure 1. The three types of coal ashes presented similar chemical composition, with a total content of main oxides (SiO2, Al2O3 and Fe2O3) above 72% and were classified as class F (according to ASTM). The analysis of ash enrichment factor showed that arsenic, zinc and lead concentrate mainly on FA, whereas the elements that presented the greatest enrichment in the bottom ash (BA) and therefore present low volatility are K and Mg. All ashes presented quartz, mullite and magnetite as crystalline phases. In the leaching and solubilization study, the FA sample was considered hazardous and classified according to Brazilian regulation as Class I solid waste, whereas CA and BA samples were considered non-hazardous and not inert solid wastes and classified as Class II-A. Therefore, FA sample from this Brazilian power plant must be discarded only after treatment or stringent disposal criteria must be followed to avoid contamination on site.

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  • IPEN-DOC 21013

    SCAPIN, MARCOS A. ; GUILHEN, SABINE N. ; COTRIM, MARYCEL E.B. ; PIRES, MARIA A.F. . Determination of Ca/P molar ratio in hydroxyapatite (HA) by x-ray fluorescence technique. In: INTERNATIONAL NUCLEAR ATLANTIC CONFERENCE; MEETING ON NUCLEAR APPLICATIONS, 12th; MEETING ON REACTOR PHYSICS AND THERMAL HYDRAULICS, 19th; MEETING ON NUCLEAR INDUSTRY, 4th, October 4-9, 2015, São Paulo, SP. Proceedings... 2015.

    Palavras-Chave: calcium; phosphorus; calcium phosphates; apatites; x-ray fluorescence analysis; calibration standards; biological materials; biological repair; bone tissues

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  • IPEN-DOC 26139

    GUILHEN, SABINE N. ; SOUZA, ALEXANDRE L.; COTRIM, MARYCEL E.B. ; PIRES, MARIA A.F. . Direct determination of aluminum in low-enriched UALx targets ( UAlx-Al) by inductively coupled plasma optical emission spectrometry. In: INTERNATIONAL NUCLEAR ATLANTIC CONFERENCE, October 21-25, 2019, Santos, SP. Proceedings... Rio de Janeiro: Associação Brasileira de Energia Nuclear, 2019. p. 298-311.

    Abstract: 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.

    Palavras-Chave: aluminium; chemical analysis; emission spectroscopy; molybdenum 99; plasma; technetium 99; uranium 235 target

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  • IPEN-DOC 27190

    BELLINI, MARIA H. ; SOUZA, ALEXANDRE L. de ; SILVA, FABIO F. da; GUILHEN, SABINE N. ; FERREIRA, RAFAEL V. de P.; OLIVEIRA, JOAO E. de ; MARUMO, JULIO T. . Essential elements as biomarkers of metastatic renal cell carcinoma. Medical & Clinical Research, v. 5, n. 7, p. 143-146, 2020. DOI: 10.33140/MCR.05.07.04

    Abstract: Renal cell carcinoma (RCC) represents 3% of human malignant tumors and approximately 90% of malignant renal neoplasms. Despite great therapeutic advances in the last decade, metastatic RCC (mRCC) is still considered an incurable disease. In this study, we examined the potential of essential elements as biomarkers of mRCC using an orthotropic metastatic mouse model. Frozen lung and plasma samples from healthy and mRCC-induced mice were lyophilized, digested, and analyzed using inductively coupled plasma mass spectrometry. In metastatic lungs, a significant increase in Ca concentration (268%) was observed, whereas a significant decrease in Cu (23.2%), Fe (17.4%), Mn (38.8%), and Na (11.7%) was observed. The plasma of mRCC-induced mice showed decreased concentrations of Mn (53%), Na (19.7%) and Zn (49,50%) and increased levels of Ca (53%), Cu (39.5%), Our findings revealed marked differences in the concentrations of essential elements in the lung and plasma of the metastatic mouse model. The circulating levels of Ca, Cu, Mn, Na, and Zn could be utilized as diagnostic and therapeutic response biomarkers.

    Palavras-Chave: carcinomas; kidneys; biological markers; elements; metastases; icp mass spectroscopy; metabolism; tumor cells; transformations; trace amounts

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  • IPEN-DOC 21152

    CORREA, WAGNER C. ; GUILHEN, SABINE N. ; ORTIZ, NILCE ; FUNGARO, DENISE A. . Evaluation of adsorption of uranium from aqueous solution using biochar materials. In: INTERNATIONAL NUCLEAR ATLANTIC CONFERENCE; MEETING ON NUCLEAR APPLICATIONS, 12th; MEETING ON REACTOR PHYSICS AND THERMAL HYDRAULICS, 19th; MEETING ON NUCLEAR INDUSTRY, 4th, October 4-9, 2015, São Paulo, SP. Proceedings... 2015.

    Palavras-Chave: adsorption; uranium; aqueous solutions; adsorbents; bamboo; eucalyptuses; nuts

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  • IPEN-DOC 19339

    GUILHEN, SABINE N. ; SOUZA, ALEXANDRE L. de; KAKAZU, MAURICIO H. ; COTRIM, MARYCEL E.B. ; PIRES, MARIA A.F. . Evaluation of analytical procedures for the determination of cadmium, boron and lithium in UAlx samples by inductively coupled plasma optical emission spectrometry (ICP OES). In: INTERNATIONAL NUCLEAR ATLANTIC CONFERENCE; MEETING ON NUCLEAR APPLICATIONS, 11th; MEETING ON REACTOR PHYSICS AND THERMAL HYDRAULICS, 18th; MEETING ON NUCLEAR INDUSTRY, 3rd, November 24-29, 2013, Recife, PE. Proceedings... Sao Paulo: ABEN, 2013, 2013.

    Palavras-Chave: aluminium; analytical solution; boron; cadmium; divinylbenzene; emission spectroscopy; extraction chromatography; iear-1 reactor; impurities; lithium; targets; uranium

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  • IPEN-DOC 22635

    SILVA, FLAVIA R.O. ; LIMA, NELSON B. ; GUILHEN, SABINE N. ; COURROL, LILIA C.; BRESSIANI, ANA H.A. . Evaluation of europium-doped HA/'beta'TCP ratio fluorescence in biphasic calcium phosphate nanocomposites controlled by the pH value during. Journal of Luminescence, v. 180, p. 177-182, 2016. DOI: 10.1016/j.jlumin.2016.08.030

    Abstract: Europium-doped hydroxyapatite (HA), beta-tricalcium phosphate (β-TCP) and biphasic phosphate nanopowders were synthesized by co-precipitation method and their crystal structures and fluorescence properties were investigated depending on the pH of the starting solution. In the range of pH 6–10, HA and β-TCP phases coexist. The β-TCP proportion increased as the pH of the solution decreased, while HA yields decreased. At pH below 6, monophasic β-TCP powder was obtained after thermal treatment. In particular, HA and β-TCP can be used as luminescent materials when activated by Eu3þ ions in substitution of Ca2þ ions. Herein, the Eu3þ ions doped HA and β-TCP phase composition were analyzed in order to investigate the fluorescence emission of the HA, β-TCP and biphasic compounds. Eu-doped HA exhibited a red-orange emission at 575 nm with several minor peaks at 610–640 nm, while Eu-doped β- TCP had an unexpected strong red emission at 610–620 nm and a secondary band at 590–600 nm. In fact, the Eu:β-TCP integrated emission area is almost 20-fold higher than Eu:HA for the same europium ion concentration. These results demonstrate the potential of Eu:β-TCP as biomarker for medical applications, as drug release and targeting based on their luminescent properties

    Palavras-Chave: evaluation; doped materials; europium; apatites; calcium phosphates; phosphates; fluorescence; synthesis; nanocomposites; ph value

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  • IPEN-DOC 27252

    ROVANI, SUZIMARA ; SANTOS, JONNATAN J.; GUILHEN, SABINE N. ; CORIO, PAOLA; FUNGARO, DENISE A. . Fast, efficient and clean adsorption of bisphenol-A using renewable mesoporous silica nanoparticles from sugarcane waste ash. RSC Advances, v. 10, n. 46, p. 27706–27712, 2020. DOI: 10.1039/d0ra05198e

    Abstract: Even with all the biological problems associated with bisphenol-A (BPA), this chemical is still being widely used, especially in thermal paper receipts. In this study, renewable mesoporous silica nanoparticles (MSN), obtained from sugarcane ash, functionalized with hexadecyltrimethylammonium (CTAB) were applied as an adsorbent in the removal of BPA from the aqueous solution. The versatility of this material and its BPA adsorption capacity were tested at different pH values, being practically constant at pH between 4 and 9, with a slight increase in pH 10 and a greater increase in pH 11. The removal time evaluation indicates a very fast adsorption process, removing almost 90% of BPA in the first 20 min of contact. The kinetic model indicates a monolayer formation of BPA molecules on the MSN-CTAB surface. The maximum adsorption capacity (Qmax) was 155.78 mg g-1, one of the highest found in literature, and the highest for material from a renewable source.

    Palavras-Chave: organic compounds; plastics; adsorption; sugar cane; ashes; bagasse; polymers; aqueous solutions; silica; nanoparticles; cleaning

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  • IPEN-DOC 24782

    RONQUIM, FLAVIA M.; COTRIM, MARYCEL E.B. ; GUILHEN, SABINE N. ; BERNARDO, ANDRE; SECKLER, MARCELO M.. Improved barium removal and supersaturation depletion in wastewater by precipitation with excess sulfate. Journal of Water Process Engineering, v. 23, p. 265-276, 2018. DOI: 10.1016/j.jwpe.2018.04.007

    Abstract: Barium ions found in wastewaters cause incrustation on membrane separation equipment used in desalination systems. In this study barium removal by precipitation is addressed, considering excess sulfate addition as a means of reducing barium concentration in solution and depleting BaSO4 supersaturation. Precipitation is conducted with synthetic wastewater in semicontinuous mode. For low excess sulfate, an induction time of a few hours is observed. As the excess sulfate is increased and/or as barium sulfate seeds are added, precipitation proceeds within a few minutes. Besides, the excess sulfate improves barium ion removal due to the common-ion effect. Residual supersaturation ratios were found to lie within the range of 1.1–3. These values were associated with a fourth order dependency of the molecular growth rate with the supersaturation ratio. Calcium carbonate and calcium sulfate dihydrate were found to be ineffective heterogeneous seeds to barium sulfate precipitation. Calcium ions were found to inhibit BaSO4 precipitation, blocking the process at a high residual supersaturation ratio of 4–5. For a sufficiently large initial supersaturation, the solution approaches equilibrium after 180 min.

    Palavras-Chave: waste water; ground water; barium sulfates; precipitation; crystal growth

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  • IPEN-DOC 24147

    GUILHEN, SABINE N. ; COLETI, JORGE; TENORIO, JORGE A.S.; FUNGARO, DENISE A. . Influence of pyrolytic temperature on uranium adsorption capability by biochar derived from macauba coconut residue. In: INTERNATIONAL NUCLEAR ATLANTIC CONFERENCE, October 22-27, 2017, Belo Horizonte, MG. Proceedings... Rio de Janeiro, RJ: Associação Brasileira de Energia Nuclear, 2017.

    Abstract: Biochar (BC) is a carbon-rich product obtained when biomass is thermally decomposed at relatively low temperatures (under 700ºC) and limited supply of oxygen in a process called pyrolysis. The conversion of biomass into BC can not only result in renewable energy source of synthetic gas and bio-oil, but also decrease the content of CO2 in the atmosphere, as well as improving soil fertility. Because of its porous structure, charged surface and surface functional groups, BC exhibits a great potential as an adsorbent. Brazilian agro energy chain involves tons of biomass waste, providing a wide range of biomasses with different chemical and physical properties. BC characteristics strongly depend on the feedstock and the pyrolysis conditions, in which the temperature is the key parameter. The aim of this study was to evaluate the adsorption potential for the removal of uranium, U(VI), from aqueous solutions using BC obtained through the pyrolysis of the macauba (Acrocomia aculeata) coconut endocarp as a function of the final pyrolytic temperature. BCs produced at higher temperatures are likely to present lower H/C and O/C ratios, indicating the loss of easily degradable carbon compounds such as volatile matter. In contrast, low-temperature pyrolysis produces not only a higher BC yield, but also richer in surface functional groups which will likely enable interactions with the U(VI) ions. The endocarp was subjected to six different pyrolytic temperatures, ranging from 250 ºC to 750 ºC. The influence of parameters such as pH, sorbent dose and initial concentration on the adsorption of U(VI) was investigated. The maximum adsorption capacity (q) was achieved for the BC obtained at 250°C (BC250), which presented a removal percentage of approx. 86%, demonstrating the potential of the BC from macauba endocarp for treatment of wastewaters. Thus, submitting the endocarp to temperatures higher than 250°C becomes unnecessary, saving time and reducing operating costs.

    Palavras-Chave: adsorption; aqueous solutions; biological materials; chars; coconuts; concentration ratio; ph value; pyrolysis; removal; temperature dependence; uranium; waste water

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  • IPEN-DOC 25729

    GUILHEN, SABINE N. ; ROVANI, SUZIMARA ; PITOL FILHO, LUIZILDO; FUNGARO, DENISE A. . Kinetic study of uranium removal from aqueous solutions by macaúba biochar. Chemical Engineering Communications, v. 206, n. 11, p. 1365-1377, 2019. DOI: 10.1080/00986445.2018.1533467

    Abstract: Macaúba (Acronomia aculeata) is a palm tree native of the Brazilian savanna and a valuable renewable source of vegetable oil for human consumption and biodiesel production. In this study, the potentiality of the macaúba endocarp for biochar (BC) production was demonstrated. Moisture, density, elemental and molecular composition, along with TGA, FTIR, and XRD analyses were performed for the endocarp. Adsorption of uranyl ions, U(VI), from aqueous solutions was studied by batch technique using BC produced by slow pyrolysis of the endocarp at 350 °C (BC350). The effect of contact time on the removal of U(VI) by BC350 was evaluated. Linear and non-linear kinetics models were employed and the best fit for the experimental data was achieved for pseudo-first order non-linear model. The adsorption equilibrium was attained after 180 min of contact time and the equilibrium adsorption capacity achieved was of 400mg g-1. Finally, BC350 was characterized by SEM, FTIR, WDXRF, and XRD techniques.

    Palavras-Chave: kinetics; uranium; aqueous solutions; adsorption; trees; coconut palms; carbon; pyrolytic carbon

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  • IPEN-DOC 26715

    VILLIBOR, FERNANDA F.; GUILHEN, SABINE N. ; DANTAS, ELIZABETH S.K. ; PIRES, MARIA A.F. . Mercury exposure among dental staff in the Legal Amazon. In: CATAPAN, EDILSON A. (Org.). Ciências da saúde: conceitos e perspectivas. São José dos Pinhais, PR: Brazilian Journals Editora, 2019. p. 198-211, v. 1, cap. 14.

    Abstract: 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.

    Palavras-Chave: dentistry; mercury; occupational exposure; mercury alloys; monitoring; absorption spectroscopy; validation

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A pesquisa no RD utiliza os recursos de busca da maioria das bases de dados. No entanto algumas dicas podem auxiliar para obter um resultado mais pertinente.

✔ É possível efetuar a busca de um autor ou um termo em todo o RD, por meio do Buscar no Repositório , isto é, o termo solicitado será localizado em qualquer campo do RD. No entanto esse tipo de pesquisa não é recomendada a não ser que se deseje um resultado amplo e generalizado.

✔ A pesquisa apresentará melhor resultado selecionando um dos filtros disponíveis em Navegar

✔ Os filtros disponíveis em Navegar tais como: Coleções, Ano de publicação, Títulos, Assuntos, Autores, Revista, Tipo de publicação são autoexplicativos. O filtro, Autores IPEN apresenta uma relação com os autores vinculados ao IPEN; o ID Autor IPEN diz respeito ao número único de identificação de cada autor constante no RD e sob o qual estão agrupados todos os seus trabalhos independente das variáveis do seu nome; Tipo de acesso diz respeito à acessibilidade do documento, isto é , sujeito as leis de direitos autorais, ID RT apresenta a relação dos relatórios técnicos, restritos para consulta das comunidades indicadas.

A opção Busca avançada utiliza os conectores da lógica boleana, é o melhor recurso para combinar chaves de busca e obter documentos relevantes à sua pesquisa, utilize os filtros apresentados na caixa de seleção para refinar o resultado de busca. Pode-se adicionar vários filtros a uma mesma busca.

Exemplo:

Buscar os artigos apresentados em um evento internacional de 2015, sobre loss of coolant, do autor Maprelian.

Autor: Maprelian

Título: loss of coolant

Tipo de publicação: Texto completo de evento

Ano de publicação: 2015

✔ Para indexação dos documentos é utilizado o Thesaurus do INIS, especializado na área nuclear e utilizado em todos os países membros da International Atomic Energy Agency – IAEA , por esse motivo, utilize os termos de busca de assunto em inglês; isto não exclui a busca livre por palavras, apenas o resultado pode não ser tão relevante ou pertinente.

✔ 95% do RD apresenta o texto completo do documento com livre acesso, para aqueles que apresentam o significa que e o documento está sujeito as leis de direitos autorais, solicita-se nesses casos contatar a Biblioteca do IPEN, bibl@ipen.br .

✔ Ao efetuar a busca por um autor o RD apresentará uma relação de todos os trabalhos depositados no RD. No lado direito da tela são apresentados os coautores com o número de trabalhos produzidos em conjunto bem como os assuntos abordados e os respectivos anos de publicação agrupados.

✔ O RD disponibiliza um quadro estatístico de produtividade, onde é possível visualizar o número dos trabalhos agrupados por tipo de coleção, a medida que estão sendo depositados no RD.

✔ Na página inicial nas referências são sinalizados todos os autores IPEN, ao clicar nesse símbolo será aberta uma nova página correspondente à aquele autor – trata-se da página do pesquisador.

✔ Na página do pesquisador, é possível verificar, as variações do nome, a relação de todos os trabalhos com texto completo bem como um quadro resumo numérico; há links para o Currículo Lattes e o Google Acadêmico ( quando esse for informado).

ATENÇÃO!

ESTE TEXTO "AJUDA" ESTÁ SUJEITO A ATUALIZAÇÕES CONSTANTES, A MEDIDA QUE NOVAS FUNCIONALIDADES E RECURSOS DE BUSCA FOREM SENDO DESENVOLVIDOS PELAS EQUIPES DA BIBLIOTECA E DA INFORMÁTICA.

O gerenciamento do Repositório está a cargo da Biblioteca do IPEN. Constam neste RI, até o presente momento 20.950 itens que tanto podem ser artigos de periódicos ou de eventos nacionais e internacionais, dissertações e teses, livros, capítulo de livros e relatórios técnicos. Para participar do RI-IPEN é necessário que pelo menos um dos autores tenha vínculo acadêmico ou funcional com o Instituto. Nesta primeira etapa de funcionamento do RI, a coleta das publicações é realizada periodicamente pela equipe da Biblioteca do IPEN, extraindo os dados das bases internacionais tais como a Web of Science, Scopus, INIS, SciElo além de verificar o Currículo Lattes. O RI-IPEN apresenta também um aspecto inovador no seu funcionamento. Por meio de metadados específicos ele está vinculado ao sistema de gerenciamento das atividades do Plano Diretor anual do IPEN (SIGEPI). Com o objetivo de fornecer dados numéricos para a elaboração dos indicadores da Produção Cientifica Institucional, disponibiliza uma tabela estatística registrando em tempo real a inserção de novos itens. Foi criado um metadado que contém um número único para cada integrante da comunidade científica do IPEN. Esse metadado se transformou em um filtro que ao ser acionado apresenta todos os trabalhos de um determinado autor independente das variáveis na forma de citação do seu nome.

A elaboração do projeto do RI do IPEN foi iniciado em novembro de 2013, colocado em operação interna em julho de 2014 e disponibilizado na Internet em junho de 2015. Utiliza o software livre Dspace, desenvolvido pelo Massachusetts Institute of Technology (MIT). Para descrição dos metadados adota o padrão Dublin Core. É compatível com o Protocolo de Arquivos Abertos (OAI) permitindo interoperabilidade com repositórios de âmbito nacional e internacional.

1. Portaria IPEN-CNEN/SP nº 387, que estabeleceu os princípios que nortearam a criação do RDI, clique aqui.


2. A experiência do Instituto de Pesquisas Energéticas e Nucleares (IPEN-CNEN/SP) na criação de um Repositório Digital Institucional – RDI, clique aqui.

O Repositório Digital do IPEN é um equipamento institucional de acesso aberto, criado com o objetivo de reunir, preservar, disponibilizar e conferir maior visibilidade à Produção Científica publicada pelo Instituto, desde sua criação em 1956.

Operando, inicialmente como uma base de dados referencial o Repositório foi disponibilizado na atual plataforma, em junho de 2015. No Repositório está disponível o acesso ao conteúdo digital de artigos de periódicos, eventos, nacionais e internacionais, livros, capítulos, dissertações, teses e relatórios técnicos.

A elaboração do projeto do RI do IPEN foi iniciado em novembro de 2013, colocado em operação interna em julho de 2014 e disponibilizado na Internet em junho de 2015. Utiliza o software livre Dspace, desenvolvido pelo Massachusetts Institute of Technology (MIT). Para descrição dos metadados adota o padrão Dublin Core. É compatível com o Protocolo de Arquivos Abertos (OAI) permitindo interoperabilidade com repositórios de âmbito nacional e internacional.

O gerenciamento do Repositório está a cargo da Biblioteca do IPEN. Constam neste RI, até o presente momento 20.950 itens que tanto podem ser artigos de periódicos ou de eventos nacionais e internacionais, dissertações e teses, livros, capítulo de livros e relatórios técnicos. Para participar do RI-IPEN é necessário que pelo menos um dos autores tenha vínculo acadêmico ou funcional com o Instituto. Nesta primeira etapa de funcionamento do RI, a coleta das publicações é realizada periodicamente pela equipe da Biblioteca do IPEN, extraindo os dados das bases internacionais tais como a Web of Science, Scopus, INIS, SciElo além de verificar o Currículo Lattes. O RI-IPEN apresenta também um aspecto inovador no seu funcionamento. Por meio de metadados específicos ele está vinculado ao sistema de gerenciamento das atividades do Plano Diretor anual do IPEN (SIGEPI). Com o objetivo de fornecer dados numéricos para a elaboração dos indicadores da Produção Cientifica Institucional, disponibiliza uma tabela estatística registrando em tempo real a inserção de novos itens. Foi criado um metadado que contém um número único para cada integrante da comunidade científica do IPEN. Esse metadado se transformou em um filtro que ao ser acionado apresenta todos os trabalhos de um determinado autor independente das variáveis na forma de citação do seu nome.