Remediação de drenagem ácida de mina usando zeólitas sintetizadas a partir de cinzas leves de carvão

Zeolitic material was synthesized from coal fly ashes (baghouse filter fly ash and cyclone filter fly ash) by hydrothermal alkaline activation. The potential application of the zeolitic product for decontamination of waters from acid mine drainage was evaluated. The results showed that a dose of 30 g L-1 of zeolitic material allowed the water to reach acceptable quality levels after treatment. Both precipitation and cation-exchange processes accounted for the reduction in the pollutant concentration in the treated waters.

Adsorção de fenol sobre carvão ativado em meio alcalino

The present study describes phenol adsorption on commercial active carbon (CAF) under alkaline conditions in the concentration range of 0.01 to 2.08 mmol L-1. Surface characterization has been performed by means of surface area measurements, IR spectroscopy and Boehm titration. The effect of temperature on the adsorption equilibrium isotherm was investigated at 23, 30, 40, 50 and 60 °C. The results showed that adsorption capacity decreased with increasing temperature. The adsorption kinetics and the role of surface characteristics on the adsorption of phenol also discussed.

Caracterização dos produtos líquidos e do carvão da pirólise de serragem de eucalipto

This study proposes the low temperature pyrolysis as an alternative conversion process for residual biomass and for obtaining gaseous, liquid and solid chemical feedstocks. Using a bench electrical pyrolysis oven, four product fractions from eucalyptus sawdust were obtained: a gaseous one, two liquid (aqueous and oily), and a solid residue (char). These products were characterized by different analytical methods. The liquid fractions showed themselves as potential sources for input chemicals. The residual char revealed appreciable adsorption capability. The process demonstrated good efficiency, generating at least two fractions of great industrial interest: bio oil and char.

Estudo da dissolução oxidativa microbiológica de uma complexa amostra mineral contendo pirita (FeS2), Pirrotita (Fe1-xS) e Molibdenita (MoS2)

This work aims to study the oxidation of a complex molybdenite mineral which contains pyrite and pyrrotite, by Acidithiobacillus ferrooxidans. This study was performed by respirometric essays and bioleaching in shake flasks. Respirometric essays yielded the kinetics of mineral oxidation. The findings showed that sulfide oxidation followed classical Michaelis-Menten kinetics. Bioleaching in shake flasks allowed evaluation of chemical and mineralogical changes resulting from sulfide oxidation. The results demonstrated that pyrrotite and pyrite were completely oxidized in A. ferrooxidans cultures whereas molybdenite was not consumed. These data indicated that molybdenite was the most recalcitrant sulfide in the sample.

Preparação e caracterização de carvão ativado quimicamente a partir da casca de arroz

This work consists in a study about the chemical activation of charred rice hulls using NaOH as the activation agent. The influence of the naturally-occurring silica was particularly evidenced. X-ray diffraction patterns showed the formation of sodium carbonate and silicates in the activated samples, whereas thermogravimetric curves revealed a strong reduction in the ash content of these samples after washing with water. Nitrogen adsorption data indicated a microporosity development only in the washed samples, with BET surface area values of 450 and 1380 m²/g achieved for the samples activated at 800 °C starting from the precursor with or without silica, respectively.

Avaliação da influência da operação da termoelétrica a carvão na concentração dos metais e as no solo de Figueira, PR - Brasil

The aim of this work is to study metal and As concentrations in soil due to ash deposition from a coal plant at Figueira (PR), evaluating the macroelement (Al, Ca, Fe, Mg, Mn, Ti, V) and microelement (As, Cd, Co, Cr, Cu, Mo, Ni, Pb, Zn) concentrations in the soil around the coal plant. The plant operation caused a slight increase in the majority of the metal concentrations in the top soil close to the plant (up to 1 km) in the wind direction (NW). The elements As, Cd, Mo, Pb and Zn are considered likely soil pollutants, and As is considered the only critical element.

Mineral and vitamin content of beef, chicken, and turkey hydrolysates mineral and vitamin content of protein hydrolysates

The purpose of this study was to assess the concentration of vitamins and minerals in meat protein hydrolysates. Calcium, phosphorus and iron were analyzed by inductively coupled-plasma atomic emission spectrophotometry; vitamin C was analyzed by the reduction of cupric ions and vitamins B1 and B2 by fluorescence. Regarding minerals, the beef hydrolysate (BH) had more iron than the turkey hydrolysate (TH) and the chicken hydrolysate (CH); TH had a little more phosphorus. BH had the largest amount of vitamin C, and similar amounts of vitamins B1 and B2. The amount of these nutrients found in the hydrolysates suggests that it is possible to use them to enrich special dietary formulations.

A thermogravimetric analysis of the combustion of a Brazilian mineral coal

Knowledge of coal combustion kinetics is crucial for burner design. This work aims to contribute on this issue by determining the kinetics of a particular Brazilian bituminous coal. Non-isothermal thermogravimetry was applied for determining both the pre-exponential factor and the activation energy. Coal samples of 10 mg and 775 mm mean size were used in synthetic air atmospheres (21 % O2). Heating rates from 10 to 50 ºC/min were applied until the temperature reached 850 ºC, which was kept constant until burnout. The activation energy for the primary and the secondary combustion resulted, respectively, in 135.1 kJ/mol and 85.1 kJ/mol.

Bioprocessos para remoção de dióxido de carbono e óxido de nitrogênio por micro-algas visando a utilização de gases gerados durante a combustão do carvão

The aim of this work was to study the removal of CO2 and NO by microalgae and to evaluate the kinetic characteristics of the cultures. Spirulina sp. showed µmax and Xmax (0.11 d-1, 1.11 g L-1 d-1) when treated with CO2 and NaNO3. The maximum CO2 removal was 22.97% for S. obliquus treated with KNO3 and atmospheric CO2. The S. obliquus showed maximum NO removal (21.30%) when treated with NO and CO2. Coupling the cultivation of these microalgae with the removal of CO2 and NO has the potential not only to reduce the costs of culture media but also to offset carbon and nitrogen emissions.

Preparação e caracterização de carvão ativado produzido a partir de resíduos do beneficiamento do café

Coffee fruit processing is one of the most polluting activities in agriculture due to the large amount of waste generated in the process. In this work, coffee parchment was employed as precursor for the production of carbons activated with ZnCl2 (CAP). The material was characterized using N2 adsorption/desorption at 77 K, Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). The material showed a surface area of 521.6 m²g-1 and microporous structure. CAP was applied as adsorbent for the removal of methylene blue dye in aqueous medium. The adsorption capacity was found to be about 188.7 mg g-1.

Determinação da matéria-prima utilizada na produção do biodiesel adicionado ao diesel mineral através de monitoramento seletivo de íons

The selective ion monitoring acquisition mode in mass spectrometry was applied to identify, in the diesel complex matrix, the raw materials (vegetable oil and alcohol) that originate biodiesel. Biodiesel samples obtained from babassu, castor, palm and soybean vegetable oils and pure fatty acid methyl and ethyl esters were used to develop this method, using specific fragments in mass spectrometry and the "window system" in gas chromatography. The commercial Brazilian B2 samples were found to be produced with soybean oil, transesterified with methanol.

Caracterização de bauxita ativada antes e depois da saturação com óleo mineral isolante

A characterization of activated bauxite and of activated bauxite impregnated with insulating mineral oil was made. The activated bauxite is used as adsorbent material in percolators during the regeneration of insulating mineral oil. After regeneration an insulating mineral oil is obtained with physical and chemical characteristics similar to those of the new oil. Moreover, saturated activated bauxite impregnated with insulating mineral oil is also produced. It is a dangerous residue according to NBR 10004 (Class I) and, thus, harmful to the environment. An alternative use of this waste in the ceramic industry is discussed.

Preparação de carvão ativado em baixas temperaturas de carbonização a partir de rejeitos de café: utilização de FeCl3 como agente ativante

Ferric chloride as a new activating agent was used to obtain activated carbons from agroindustrial waste. This material was prepared at three temperatures of pyrolysis, 200, 280 and 400 ºC. The carbonaceous materials obtained after the activation processes showed high specific surface areas (BET), with values higher than 900 m² g-1. The materials showed different behaviors in the adsorption of methylene blue dye and reactive red textile dye in water solutions. An important fact in the use of FeCl3 as an activating agent is that the activation temperature is at 280 ºC, well below of those commonly employed in chemical or physical activations described in the literature.

Björneborgs läns mineral-historia

Invocatio: M.G.H.

Tavastlands mineral-historia

Invocatio: M.G.H.