Estudo comprarativo da biossorção dos metais terras-raras ('ND POT. +3', 'LA POT. +3', 'CE POT. +3') pela biomassa melanizada e pigmento, na forma livre e imobilizada, obtidos do fungo Aspergillus nidulans

Pós-graduação em Biotecnologia - IQ

Comparação da biossorção de metais terras-raras pela biomassa melanizada do fungo Aspergillus nidulans nas formas livre e imobilizada

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Estudo da concentração e recuperação de íons lantânio e neodímio por biossorção em coluna com a biomassa Sargassum sp

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Comparação dos parâmetros de biossorção dos elementos terras-raras lantânio e neodímio utilizando biomassas de fungos filamentosos

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Remoção de metais pesados de soluções usando um biopolímero

Comunicação seleccionada e artigo em Livro de Actas

Biossorção de terras-raras por Sargassum sp: estudos preliminares sobre as interações metal-biomassa e a potencial aplicação do processo para a concentração , recuperação e separação de metais de alto valor agregado em colunas empacotadas

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Mucorales de solo contaminado com metais pesados na região do pólo cerâmico de Santa Gertrudes, SP: ocorrência e capacidade de biossorção de chumbo e zinco

Pós-graduação em Ciências Biológicas (Microbiologia Aplicada) - IBRC

Remoção de metais usando casca de amendoim

Mestrado em Engenharia Química

Biossorção utilizando alga marinha (sargassum sp.) aplicada em meio orgânico

In this work, biosorption process was used to remove heavy metals from used automotive lubricating oils by a bus fleet from Natal-RN-Brazil. This oil was characterized to determine the physical-chemistry properties. It was also characterized the used oil with the aim of determining and quantifying the heavy metal concentration. Fe and Cu were the metals existent in large concentration and these metals were choused to be studied in solubilization process. For the biosorption process was used the seaweed Sargassum sp for the study of influencing of the metals presents separately and with other metals. It was also studied the effect of the protonation treatment of alga with the objective to know the best efficiency of heavy metals removal. The study of the solubilization showed that the presence of more than a metal favors the solubilization of the metals presents in the oil and consequently, it favors the biosorption process, what becomes interesting the perspective application in the heavy metals removal in lubricating oils used, because the presence of more than a heavy metal favors the solubility of all metals present. It was observed that the iron and copper metals, which are present in large concentration, the protonated biosorbtent was more effective. In this study we used as biomass the marine alga Sargassum sp to study the influence of agitation velocity, temperature and initial biomass concentration on the removal of iron and copper from used lubricant oils. We performed an experimental design and a kinetic study. The experiments were carried out with samples of used lubricant oil and predetermined amounts of algae, allowing sufficient time for the mixture to obtain equilibrium under controlled conditions. The results showed that, under the conditions studied, the larger the amount of biomass present, the lower the adsorption capacity of the iron and of the copper, likely due to a decrease in interface contact area. The experimental design led us to conclude that a function can be obtained that shows the degree of influence of each one of the system variables

Produção de exo-biopolímeros por ascomicetos e seu potencial de utilização na biossorção de cádmio e chumbo

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Estudo de equilíbrio e cinética da biossorção de cobre (II) por Rhizopus Microsporus.

A poluição relacionada a metais pesados tem recebido uma atenção especial devido a sua alta toxicidade, não biodegradabilidade e tendência de acumular-se na cadeia alimentar. Apesar disso, metais pesados também são considerados recursos valiosos, portanto a sua remoção em conjunto com a sua recuperação torna-se ainda mais importante. Este caso aplica-se aos rejeitos de mineração de cobre, os quais oferecem a possibilidade de recuperação do metal e de sua contenção de maneira segura do meio ambiente. Tais rejeitos se caracterizam por ocuparem enormes áreas inundadas e abrigarem soluções diluídas de cobre (II), porém, muitas vezes, acima dos limites seguros. Diversos processos tradicionais de tratamento mostram-se disponíveis para remover o cobre de tais soluções, no entanto, em certas aplicações eles podem ser ineficientes ou muito onerosos. Nesse contexto, a biossorção é uma alternativa interessante. Nesse processo, certos microrganismos, como fungos, bactérias e algas, ligam-se passivamente ao cobre na forma íons ou outras moléculas em soluções. No presente trabalho foi avaliado o potencial de biossorção de íons cobre (II) pela biomassa do fungo Rhizopus microsporus, coletado e isolado da área de rejeitos da Mina do Sossego, na região norte do Brasil. Isotermas de biossorção foram determinadas experimentalmente em bateladas sob temperatura de 25°C, agitação de 150 rpm, concentração de biomassa de 2,0 a 2,5 g/L e tempo de contato mínimo de 4 horas. O pH mostrou ser um fator importante no equilíbrio da biossorção, sendo o valor máximo da capacidade de biossorção de 33,12 mg de cobre / g biomassa encontrado em pH 6. Valores sucessivamente menores são encontrados pela acidificação da solução, sendo o pH 1 considerado adequado para o processo de dessorção, correspondendo a uma capacidade de biossorção de 1,95 mg/g. Modelos de adsorção de Langmuir e de Freundlich ajustaram-se adequadamente às isotermas tanto com pH controlado quanto não controlado. Foi constatado que a troca iônica é um dos mecanismos envolvidos na biossorção do cobre com Rhizopus microsporus. Tanto o modelo de pseudo-primeira ordem quanto o de pseudo-segunda ordem ajustaram-se aos dados cinéticos da biossorção, sendo que o equilíbrio ocorre em aproximadamente 4 horas. A biomassa conservou a capacidade de biossorção ao operar repetidamente em três ciclos de sorção-dessorção. A biomassa viável e a morta não apresentaram diferença estatisticamente significativa na capacidade de biossorção.

Avaliação do potencial da macrófita Pistia stratiotes na exposição de íon cromo (VI): biossorção e tolerância

The environmental pollution caused by industries has increased the concentration of pollutants in the environment, especially in water. Among the most diverse contaminants, there is the metals, who may or may not to be heavy/toxic, causing effluent of difficult treatment when in low concentrations. The search for alternative measures of wastewater effluent treatment has led to studies using phytoremediation technique through the various matrices (plant, fungi, bacteria) as means of polishing treatment to remove contaminants by means of biosorption/bioaccumulation. In order to use the phytoremediation technique for removing metals of the environmental, it have been performed bioassay with the macrophyte Pistia stratiotes. The bioassays were realized with healthy plants of P. stratiotes acclimatized in a greenhouse, at room temperature and lighting conditions during 28 days of cultivate. The cultivations were performed in glass vessels containing 1 L of the hydroponic solution with chromium (VI) in the potassium dichromate form with concentration range 0.10 to 4.90 mg L-1. The experiments were performed by Outlining Central Composite Rotational (OCCR), where the kinetics of bioaccumulation and chlorophyll a fluorescence were monitored in plants of P. stratiotes during cultivation. The collections of the samples and cultive solution were performed according to the OCCR. The chromium levels were measured in samples of P. stratiotes and the remaining solutions by the methodology of atomic absorption spectrometry by flame. The tolerance of P. stratiotes in relation to exposure to chromium (VI) was analyzed by parameters of physiological activity by means of chlorophyll a fluorescence, using the portable fluorometer PAM (Pulse Amplitude Modulation). The development of P. stratiots and their biomass were related to the time factor, while bioaccumulation capacities were strongly influenced by factors of time and chromium concentration (VI). The chlorophyll fluorescence parameters were affected by chromium and the exposure time at the bioassays. It was obtained an higher metal removal from the root in relation to the sheet, reaching a high rate of metal removal in solution. The experimental data removal kinetics were represented by kinetic models Irreversibly Langmuir, Reversible Langmuir, Pseudo-first Order and Pseudo-second Order, and the best fit for the culture solution was the Reversible Langmuir model with R² 0.993 and for the plant the best model was Pseudo-second order with R² 0.760.

Desempenho analítico de laboratórios prestadores de serviço na determinação de metais em águas

Analytical laboratories are expected to produce reliable results. Decision makers are guided in their actions (financial, legal and environmental) using analytical data provided by numerous laboratories. This work aimed to evaluate the analytical performance of Brazilian laboratories on producing trustworthy results. Nineteen laboratories, accredited and non-accredited ones, were contracted to analyze a USGS (United States Geological Survey) certified water sample for 17 chemical elements (mostly metals) without knowing the origin of the sample. Considering all the results produced, only 35% of them were valid. Three laboratories present satisfactory performances, whereas the majority showed a very poor overall performance. The outcomes of this work show the need for a more effective analytical quality program to Brazilian laboratories.

Estudo por espectroscopia micro-Raman dos mecanismos de separação de fase em vidros fosfatos de metais de transição

Glass-ceramics are prepared by controlled separation of crystal phases in glasses, leading to uniform and dense grain structures. On the other hand, chemical leaching of soluble crystal phases yields porous glass-ceramics with important applications. Here, glass/ceramic interfaces of niobo-, vanado- and titano-phosphate glasses were studied by micro-Raman spectroscopy, whose spatial resolution revealed the multiphase structures. Phase-separation mechanisms were also determined by this technique, revealing that interface composition remained unchanged as the crystallization front advanced for niobo- and vanadophosphate glasses (interface-controlled crystallization). For titanophosphate glasses, phase composition changed continuously with time up to the equilibrium composition, indicating a spinodal-type phase separation.

Sulfetos volatilizáveis por acidificação e metais extraídos simultaneamente na avaliação de sedimentos de água doce

This paper discusses the historical and methodological fundaments of the dynamics and quantification of acid volatile sulfides (AVS) and simultaneously extracted metals (SEM) in aquatic sediments. It also discusses the SEM/AVS relationship, which involves several controversial aspects such as sulfide stability, sulfide-organic matter interaction, and the inability to predict the toxicity of organic compounds in the environment. This relationship is an important tool for the inference of metal bioavailability. The use of ecotoxicological tests with target organisms regulated by international standards is also a relevant aspect.