LUDMILA CABREIRA VIEIRA

LUDMILA CABREIRA VIEIRA

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Biosorption of uranium from aqueous solutions by Azolla sp. and Limnobium laevigatum
2022 - ARAUJO, LEANDRO G. de; VIEIRA, LUDMILA C.; CANEVESI, RAFAEL L.S.; SILVA, EDSON A. da; WATANABE, TAMIRES; FERREIRA, RAFAEL V. de P.; MARUMO, JULIO T.
The main goal of this study was to assess alternatives to the current challenges on environmental quality and circular economy. The former is here addressed by the treatment of radioactively contaminated solutions, and the latter by using abundant and low-cost biomass. In this paper, we examine the biosorption of hexavalent uranium (U(VI)) in a batch system using the macrophytes Limnobium laevigatum and Azolla sp. by three operational parameters: biomass dose, metal ion concentration, and contact time. Simulated solutions were firstly addressed with two biomasses, followed by studies with real liquid organic radioactive waste (LORW) with Azolla sp. The batch experiments were carried out by mixing 0.20 g biomass in 10 mL of the prepared solution or LORW. The total contact time employed for the determination of the equilibrium times was 240 min, and the initial U(VI) concentration was 0.63 mmol L−1. The equilibrium times were 15 min for L. laevigatum and 30 min for Azolla sp. respectively. A wide range of initial U(VI) concentrations (0.25–36 mmol L−1) was then used to assess the adsorption capacity of each macrophyte. Isotherm models validated the adsorption performance of the biosorption process. Azolla sp. presented a much higher U(VI) uptake (0.474 mmol g−1) compared to L. laevigatum (0.026 mmol g−1). When in contact with LORW, Azolla sp. removed much less uranium, indicating an adsorption capacity of 0.010 mmol g−1. In conclusion, both biomasses, especially Azolla sp., can be used in the treatment of uranium-contaminated solutions.
Uranium biosorption by Lemna sp. and Pistia stratiotes
2019 - VIEIRA, LUDMILA C.; ARAUJO, LEANDRO G. de; FERREIRA, RAFAEL V. de P.; SILVA, EDSON A. da; CANEVESI, RAFAEL L.S.; MARUMO, JULIO T.
Biosorption-based technologies have been proposed for the removal of radionuclides from radioactive liquid waste containing organic compounds. Nevertheless, pytoremediation potential of uranium (U) by nonliving aquatic macrophytes Lemna sp. and Pistia stratiotes has not been previously addressed. In this study, uranium biosorption capacity by Pistia stratiotes and Lemna sp. was evaluated by equilibrium and kinetics experiments. The biomasses were added to synthetic and real waste solutions. The assays were tested in polypropylene vials containing 10 mL of uranium nitrate solution and 0.20 g of biomass. Solutions ranging from 0.25 to 84.03 mmol l−1 were employed for the assessment of uranium concentration in each macrophyte. The equilibrium time was 1 h for both macrophytes. Lemna sp. achieved the highest sorption capacity with the use of the synthetic solution, which was 0.68 mmol g−1 for the macrophyte. Since Lemna sp. exhibit a much higher adsorption capacity, only this biomass was exposed to the actual waste solution, being able to adsorb 9.24×10−3 mmol g−1 U (total). The results show that these materials are potentially applicable to the treatment of liquid radioactive waste.
The use of macrophytes as biosorbents in radioactive liquid waste treatment
2018 - FERREIRA, EDUARDO; VIEIRA, LUDMILA; FERREIRA, RAFAEL V. de P.; MARUMO, JULIO T.
An important stage of the management of radioactive liquid waste is the chemical treatment. In the last few years, biosorption has attracted attention as one alternative method to remove radionuclides in liquid LL/ILW due to its efficiency and low costs. There are many biomasses that can be applied for this purpose, as agricultural residues and Macrophytes. This study aims at studying Macrophytes (Pistia Stratiotes, Limnobium Laevigatum, Lemna sp and Azolla sp) ability to absorb uranium in liquid solutions. The biosorption capacity of uranium by the Macrophytes was experimentally determined. The experiments determine the metal uptake after the solution was in contact with each biosorbents by inductively coupled plasma optical emission spectrometry (ICP-OES). The results show that these materials are potentially applicable in the treatment of liquid radioactive waste.
Essential elements as biomarkers of acute kidney injury and spontaneous reversion
2018 - SILVA, REGIANE M. da; KO, GUI MI; SILVA, RINALDO F.; VIEIRA, LUDMILA C.; PAULA, RAFAEL V. de; MARUMO, JULIO T.; IKEGAMI, AMANDA; BELLINI, MARIA H.
Acute kidney injury (AKI) is an important health problem and can be caused by number of factors. The use of aminoglycosides, such as gentamicin, is one of these factors. Recently, an effort has been made to find biomarkers to guide treatment protocols. Inductively coupled plasma optical emission spectroscopy (ICP-OES) was used to estimate the contents of Ca, Cu, Fe, K, Mg, Mn, Na, P, and Zn in serum and urine of the healthy, AKI, and spontaneous recovery (SR) groups of animals. The animal model of AKI and SR was validated by measuring serum and urinary urea and creatinine. The quantitative determination of the elements showed a decrease in serum levels of Ca, and Fe in the AKI group (P<0.01 vs. healthy), with a return to normal levels in the SR group, without a significant difference between the healthy and SR groups. In the urine samples, there was a decrease in P and Na levels in the AKI group (P<0.001 and P<0.01 vs. healthy), but Ca levels were increased in this group compared with the healthy and SR groups (P<0.01). These findings indicate that mineral elements might be useful as biomarkers for AKI.
Aplicação de macrófitas como biossorventes no tratamento de rejeitos radioativos líquidos
2016 - VIEIRA, LUDMILA C.
O rejeito radioativo como qualquer outro tipo de resíduo, precisa receber tratamento adequado. É necessário considerar suas características físico-químicas e radiológicas para a escolha da ação apropriada para o tratamento e a deposição final do rejeito. Muitas técnicas de tratamento utilizadas hoje são economicamente dispendiosas, inviabilizando muitas vezes o seu uso e impulsionando o estudo de outras técnicas de tratamento. Uma dessas técnicas é a biossorção, que demonstra alto potencial quando aplicada a rejeitos radioativos. Essa técnica utiliza materiais de origem biológica para a remoção de metais. Dos potenciais biossorventes encontrados, as macrófitas aquáticas apresentam-se vantajosas e possibilitam a remoção do urânio presente no rejeito radioativo líquido a baixo custo. O objetivo deste estudo foi avaliar a capacidade de biossorção das macrófitas aquáticas Pistia stratiotes, Limnobium laevigatum, Lemna sp e Azolla sp no tratamento dos rejeitos radioativos líquidos. Este trabalho foi dividido em duas etapas, uma de caracterização e preparação e outra de ensaios de biossorção, realizados com soluções de urânio e com rejeito real. As biomassas foram testadas na sua forma bruta e os ensaios de biossorção foram realizados em frascos de polipropileno contendo 10 mL de solução de urânio ou 10 mL de rejeito radioativo e 0,20 g de biomassa. O comportamento das biomassas foi avaliado por meio da cinética de sorção e modelos de isotermas. As maiores capacidades de sorção foram observadas com as macrófitas Lemna sp com 162,1 mg/g e para a Azolla sp com 161,8 mg/g. Os tempos de equilíbrio obtidos foram de 1 hora para a Lemna sp, e de 30 minutos para a Azolla sp. Com o rejeito real, a macrófita Azolla sp apresentou uma capacidade de sorção de 2,6 mg/g. Estes resultados sugerem que a Azolla sp possui maior capacidade de biossorção, sendo a mais indicada para estudos mais detalhados de tratamento de rejeitos radioativos líquidos.
Biosorption of uranium by Azolla sp
2015 - VIEIRA, LUDMILA C.; FERREIRA, RAFAEL V. de P.; ALVES, ELIAKIM G.; CANEVESI, RAFAEL L.S.; SILVA, EDSON A.; MARUMO, JULIO T.
Biosorption of uranium in radioactive liquid organic waste by coconut fiber
2013 - MARUMO, JULIO T.; FERREIRA, EDUARDO G.A.; VIEIRA, LUDMILA C.; SILVA, EDSON A. da; FERREIRA, RAFAEL V. de P.