Adsorção de Pb(II) utilizando adsorvente composto por montmorilonita e dolomita

The destructive impact of improper disposal of heavy metals in the environment increases as a direct result of population explosion, urbanization and industrial expansion and technological developments. Argil are potential materials for adsorption of inorganic and the pelletization of it is required for use in adsorptive columns of fixed bed. The low cost and the possibility of regeneration makes these materials attractive for use in the purification process, capable of removing inorganic compounds in contaminated aquatic environments. In this work was made pellets of a mixture of dolomite and montmorillonite by wet agglomeration, in different percentages. The removal of Pb (II) was investigated through experimental studies, and was modeled by kinetic models and isotherms of adsorption. The materials were characterized using the techniques of XRD, TG / DTA, FT-IR, and surface area by BET method. The results showed the adsorption efficiency of the contaminant by the composite material studied in synthetic solution. The study found that the adsorption follows the Langmuir model, and the kinetics of adsorption follows the model of pseudosecond order

Chronic contamination assessment integrating biomarkers' responses in transplanted mussels-A seasonal monitoring

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Determinação de dados de equilíbrio líquido-vapor a altas pressões para sistemas de hidrocarbonetos assimétricos

Crude oil is a complex liquid mixture of organic and inorganic compounds that are dominated by hydrocarbons. It is a mixture of alkanes from the simplest to more complex aromatic compounds that are present derivatives such as gasoline, diesel, alcohol, kerosene, naphtha, etc.. These derivatives are extracted from any oil, however, only with a very high quality, in other words, when the content of hydrocarbons of low molecular weight is high means that production of these compounds is feasible. The American Petroleum Institute (API) developed a classification system for the various types of oil. In Brazil, the quality of most of the oil taken from wells is very low, so it is necessary to generate new technology to develop best practices for refining in order to produce petroleum products of higher commercial value. Therefore, it is necessary to study the thermodynamic equilibrium properties of its derivative compounds of interest. This dissertation aims to determine vapor-liquid equilibrium (VLE) data for the systems Phenilcyclohexane - CO2, and Cyclohexane - Phenilcyclohexane - CO2 at high pressure and temperatures between 30 to 70oC. Furthermore, comparisons between measured VLE experimental data from this work and from the literature in relation to the Peng- Robinson molecular thermodynamic model, using a simulation program SPECS IVCSEP v5.60 and two adjustable interaction parameters, have been performed for modeling and simulation purposes. Finally, the developed apparatus for determination of phase equilibrium data at high pressures is presented

Avaliação e modelagem da absorção de H2S do gás natural em coluna de leito estagnado

Natural gas, although basically composed by light hydrocarbons, also presents contaminant gases in its composition, such as CO2 (carbon dioxide) and H2S (hydrogen sulfide). The H2S, which commonly occurs in oil and gas exploration and production activities, causes damages in oil and natural gas pipelines. Consequently, the removal of hydrogen sulfide gas will result in an important reduction in operating costs. Also, it is essential to consider the better quality of the oil to be processed in the refinery, thus resulting in benefits in economic, environmental and social areas. All this facts demonstrate the need for the development and improvement in hydrogen sulfide scavengers. Currently, the oil industry uses several processes for hydrogen sulfide removal from natural gas. However, these processes produce amine derivatives which can cause damage in distillation towers, can cause clogging of pipelines by formation of insoluble precipitates, and also produce residues with great environmental impact. Therefore, it is of great importance the obtaining of a stable system, in inorganic or organic reaction media, able to remove hydrogen sulfide without formation of by-products that can affect the quality and cost of natural gas processing, transport, and distribution steps. Seeking the study, evaluation and modeling of mass transfer and kinetics of hydrogen removal, in this study it was used an absorption column packed with Raschig rings, where the natural gas, with H2S as contaminant, passed through an aqueous solution of inorganic compounds as stagnant liquid, being this contaminant gas absorbed by the liquid phase. This absorption column was coupled with a H2S detection system, with interface with a computer. The data and the model equations were solved by the least squares method, modified by Levemberg-Marquardt. In this study, in addition to the water, it were used the following solutions: sodium hydroxide, potassium permanganate, ferric chloride, copper sulfate, zinc chloride, potassium chromate, and manganese sulfate, all at low concentrations (»10 ppm). These solutions were used looking for the evaluation of the interference between absorption physical and chemical parameters, or even to get a better mass transfer coefficient, as in mixing reactors and absorption columns operating in counterflow. In this context, the evaluation of H2S removal arises as a valuable procedure for the treatment of natural gas and destination of process by-products. The study of the obtained absorption curves makes possible to determine the mass transfer predominant stage in the involved processes, the mass transfer volumetric coefficients, and the equilibrium concentrations. It was also performed a kinetic study. The obtained results showed that the H2S removal kinetics is greater for NaOH. Considering that the study was performed at low concentrations of chemical reagents, it was possible to check the effect of secondary reactions in the other chemicals, especially in the case of KMnO4, which shows that your by-product, MnO2, acts in H2S absorption process. In addition, CuSO4 and FeCl3 also demonstrated to have good efficiency in H2S removal

A route to obtain Gd2O3:Nd3+ with different particle size

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Vanadium and its complexes: The renewed interest in its biochemistry

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Avaliação da genotoxicidade das águas do lençol freático sob a Universidade Federal do Rio Grande do Norte

The groundwater represents the most important freshwater supply of planet. Dailly, in all world a great amount of toxic and genotoxic material reaches the aquatic systems, mainly the aquifers. The Barreiras aquifer through of five water wells is responsible for the supplying of Universidade Federal do Rio Grande do Norte (UFRN). All water wells are polluted with nitrate and some heavy metals, two of them were disabled. The genotoxicity of groundwater samples from Barreiras Aquifer in UFRN was assessed using the Allium cepa test, the Ames test and the Salmonella typhymurium microsuspension test (Kado test). For the Allium cepa test the influence of the groundwater samples collected on macroscopic (root length, colour and form) and microscopic (root tip mitotic index, chromosome aberrations and micronucleus) parameters was examined. All water samples caused a significant increase of the chromosome and mitotic aberration frequency and reduction on the rooth growth compared to negative control. Bridges and chromosome stickness were the most frequent kind of aberration in dividing cells. Furthermore, breaks were also observed. No significant increase in the number of micronuclei was found in relation to the negative controls. For Ames test were used the Salmonella typhymurium strains TA98 and TA100 without metabolic activation, applying the direct method. Prior to the Kado test, organic fractions from the water samples were obtained through XAD resin concentration. The mutagenicity organic extracts were evaluated by Kado test using TA98 and TA100 strains, in the absence and presence of S9 mix (metabolic activation). The concentrations of seven heavy metal ions were measured in water samples, but only Ni, Cu and Cr levels exceeded the permissible maximum concentration for the natural reservoirs. The results obtained for mutagenic activity using the Ames test were negative in all raw water samples analyzed. Positive results in XAD4 extracts of water samples were obtained for TA98 in the presence of S9 mix for two stations. Concentrations of heavy metals and nitrate can be correlated with the toxicity and genotoxicity of water analyzed. The mutagenic effect detected with TA98 strain suggested that organic compounds (after metabolization) are involved with the mutagenicity detected in the samples analyzed. The data set obtained in this work indicated the presence of at least two classes of mutagens: organic and inorganic compounds

Degradação eletroquímica de benzeno, tolueno e xileno via oxidação eletroquímica utilizando eletrodo Ti/Pt

This work is directed to the treatment of organic compounds present in produced water from oil using electrochemical technology. The water produced is a residue of the petroleum industry are difficult to treat , since this corresponds to 98 % effluent from the effluent generated in the exploration of oil and contains various compounds such as volatile hydrocarbons (benzene, toluene, ethylbenzene and xylene), polycyclic aromatic hydrocarbons (PAHs), phenols, carboxylic acids and inorganic compounds. There are several types of treatment methodologies that residue being studied, among which are the biological processes, advanced oxidation processes (AOPs), such as electrochemical treatments electrooxidation, electrocoagulation, electrocoagulation and eletroredution. The electrochemical method is a method of little environmental impact because instead of chemical reagents uses electron through reactions of oxide-reducing transforms toxic substances into substances with less environmental impact. Thus, this paper aims to study the electrochemical behavior and elimination of the BTX (benzene, toluene and xylene) using electrode of Ti/Pt. For the experiment an electrochemical batch system consists of a continuous source, anode Ti/Pt was used, applying three densities of current (1 mA/cm2, 2,5 mA/cm2 and 5 mA/cm2). The synthetic wastewater was prepared by a solution of benzene, toluene and xylene with a concentration of 5 ppm, to evaluate the electrochemical behavior by cyclic voltammetry and polarization curves, even before assessing the removal of these compounds in solution by electrochemical oxidation. The behavior of each of the compounds was evaluated by the use of electrochemical techniques indicate that each of the compounds when evaluated by cyclic voltammetry showed partial oxidation behavior via adsorption to the surface of the Ti/Pt electrode. The adsorption of each of the present compounds depends on the solution concentration but there is the strong adsorption of xylene. However, the removal was confirmed by UV-Vis, and analysis of total organic carbon (TOC), which showed a percentage of partial oxidation (19,8 % - 99,1 % TOC removed), confirming the electrochemical behavior already observed in voltammetry and cyclic polarization curves

Terpenos com atividade inseticida: uma alternativa para o controle químico de insetos

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

BLOOD-CONSTITUENTS AND ELECTROPHORETIC PATTERNS IN ANTARCTIC BIRDS - PENGUINS AND SKUAS

1. A survey has been carried out on the blood constituents of penguins from the Pygoscellidae family, Pygoscellis antartica, P. papua and P. adeliae, and of skuas (Chataracta maccormicki).2. Glucose, non-protein nitrogen compounds, proteins, lipids and inorganic compounds and the electrophoretic patterns for hemoglobin, serum proteins and lipoproteins were studied.3. The values obtained for glucose partition in the blood, glycosylated hemoglobin and non-protein nitrogen compounds, are discussed.

Effect of salt stress on polyamine metabolism in bean cell culture

The adaptive capacity of bean (Phaseolus vulgaris L.) calluses (cultivars IAC-carioca, JALO EEP-558, BAT-93 and IAPAR-14) to salt stress (0-80 mM) was verified to determine the existence of biochemical markers such as organic and inorganic compounds, and metabolism of polyamines. The results obtained demonstrate that salt (NaCl) interfered with all the parameters analyzed and its intensity ranged due to the salt concentration and the cultivars used.

Characterization of the colloidal products of pentacarbonyliron oxidation

Pentacarbonyliron was oxidized with H2O2, in organic solvents, to give colloidal sols. The aqueous-ethanolic sol is highly stable and undergoes thermally-reversible coagulation. Its solid phase was found to be a non-crystalline Fe (III) hydroxoacetate which is transformed to α-Fe2O3 when heated to 300°C. Iron-bound acetate groups are assumed to have a major role in the sol stability, by preserving the amorphous solid phase. Dry hydroxoacetate particles were heated under vacuum; scanning electron microscopy revealed that these particles coalesce and grow, as in a sintering process but at low temperatures (100-250°). © 1987.

Luminescence and non-radiative processes in lanthanide squarate hydrates

The luminescence properties of solid hydrated lanthanide squarates (Ln2(C4O4)3(H2O) x; x = 8 or 13;Ln3+ = Gd, La, Eu, Tb, Pr) are reported for temperatures down to 4.2K. The luminescence of the squarate group is observed for the Gd3+ and La3+ compounds at low temperatures (below 150K). The Pr3+ compound does not show any emission at all, not even at 4.2K. This is ascribed to the quenching of the Pr3+ emission by multiphonon relaxation and/or concentration quenching. The quantum efficiencies of the 5D0 emission of Eu3+ and of the 5D4 emission of Tb3+ in these squarate complexes are strikingly different. Whereas the Tb3+ emission shows a temperature independent quantum efficiency of 50% upon ligand excitation, the Eu3+ emission is strongly quenched, showing a temperature dependent quantum efficiency of 0.8% at 4.2K upon ligand excitation. This quenching is ascribed to the low energy position of the charge-transfer state of Eu3+ in these compounds.

Investigation of New Ion Conducting Ormolytes Silica-Polypropyleneglycol

Two groups of hybrid organic-inorganic composites exhibiting ionic conduction properties, so called ORMOLYTES (organically modified electrolytes), have been prepared by the sol-gel process. The first group has been prepared from mixture of a lithium salt and 3-isocyanatopropyltriethoxysilane(IsoTrEOS),O,O′-bis(2-aminopropyl) polypropyleneglycol. These materials produce chemical bonds between the organic (polymer) and the inorganic (silica) phases. The second group has been prepared by an ultrasonic method from a mixture of tetraethoxysilane (TEOS), polypropyleneglycol and a lithium salt. The organic and inorganic phases are not chemically bonded in these samples. The Li+ ionic conductivity, σ, of all these materials has been studied by AC impedance spectroscopy up to 100°C. Values of σ up to 10-6 Ω-1·cm-1 have been found at room temperature. A systematic study of the effects of lithium concentration, polymer chain length and the polymer to silica weight ratio on σ shows that there is a strong dependence of σ on the preparation conditions. The dynamic properties of the Li+ ion and the polymer chains as a function of temperature between -100 and 120°C were studied using 7Li solid-state NMR measurements. The ionic conductivity of both families are compared and particular attention is paid to the nature of the bonds between the organic and inorganic components.

Acid dye biodegradation using saccharomyces cerevisiae immobilized with polyethyleneimine-treated sugarcane bagasse

Chemical reagents used by the textile industry are very diverse in their composition, ranging from inorganic compounds to polymeric compounds. Strong color is the most notable characteristic of textile effluents, and a large number of processes have been employed for color removal. In recent years, attention has been directed toward various natural solid materials that are able to remove pollutants from contaminated water at low cost, such as sugarcane bagasse. Cell immobilization has emerged as an alternative that offers many advantages in the biodegradation process, including the reuse of immobilized cells and high mechanical strength, which enables metabolic processes to occur under adverse conditions of pH, sterility, and agitation. Support treatment also increases the number of charges on the surface, thereby facilitating cell immobilization processes through adsorption and ionic bonds. Polyethyleneimine (PEI) is a polycationic compound known to have a positive effect on enzyme activity and stability. The aim of the present study was to investigate a low-cost alternative for the biodegradation and bioremediation of textile dyes, analyzing Saccharomyces cerevisiae immobilization in activated bagasse for the promotion of Acid Black 48 dye biodegradation in an aqueous solution. A 1 % concentration of a S. cerevisiae suspension was evaluated to determine cell immobilization rates. Once immobilization was established, biodegradation assays with free and immobilized yeast in PEI-treated sugarcane bagasse were evaluated for 240 h using UV-vis spectrophotometry. The analysis revealed significant relative absorbance values, indicating the occurrence of biodegradation in both treatments. Therefore, S. cerevisiae immobilized in sugarcane bagasse is very attractive for use in biodegradation processes for the treatment of textile effluents. © 2012 Springer Science+Business Media Dordrecht.