Hidrólise parcial da superfície do polyethylene terephthalate (PET): transformando um rejeito em um material de troca catiônica para aplicação ambiental

In this work it is proposed a simple and versatile undergraduate chemical experiment in polymer and environmental technology based on the process of polyethylene terephthalate (PET) hydrolysis. Polyethylene terephthalate from post-consume bottles is submitted to a controlled partial hydrolysis which allows the students to follow the reaction by a simple procedure. The students can explore the reaction kinetics, the effect of catalysts and the exposed polyethylene terephthalate surface area on the hydrolysis reaction. The second and innovative part of this experiment is the technological and environmental application of the hydrolyzed polyethylene terephthalate as a material with cation exchange properties. The surface hydrolyzed polyethylene terephthalate can be used as adsorbent for cationic contaminants.

Caracterização e propriedades do material coloidal nanoestruturado β-FeOOH/bentonita

A new mixed material was obtained through the combination of the suspensions of iron oxy-hydroxide and bentonite clay, denoted BFe. Analysis of its structure (XRD, Mossbauer and TGA) and composition (AAS) suggests the maintenance of the layer structure of the clay and an increase in the thermal stability of the BFe. Electrochemical studies performed in different electrolytes show that only in an alkaline medium it is possible to observe the redox peaks relative to the processes involving Fe+2/Fe+3 pair. Tests that evaluated the potential use of the photo-Fenton process showed an efficient degradation process of the dyes in significantly reduced reaction times.

Determinação de metais traço no material particulado em suspensão em Ouro Preto, Minas Gerais

The determination of the airborne particulate matter (PTS) mass and trace metals concentrations were performed in three sites in Ouro Preto, MG, Brazil. It was evaluated 288 samples. The legal limit of annual geometric average (60 µg m-3) to PTS concentrations didn't exceed, but the legal limit for 24 h (240 µg m-3) did in three measurements. Seven metals (Al, Cr, Cu, Fe, Mn, Ni, Pb) analysed by ICP-AES were quantified in 18 samples. Aluminum and iron showed the highest concentrations, indicating the contribution of the soil and of one aluminum plant. The high nickel concentration is probably due to vehicular emissions and industrial combustion processes.

Caracterização do material particulado fino e grosso e composição da fração inorgânica solúvel em água em São José dos Campos (SP)

Air samples of fine (PM2,5) and coarse (PM2,5-10) particulate matter were collected in São José dos Campos from February 2004 to February 2005. Average PM10 mass concentrations was 31.2 ± 14.0 μg m-3, half of which belonging to the PM2.5 fraction. Ammonium and SO4(2-) were predominantly found in the fine fraction. Average (NH4)2SO4 concentration was estimated to be about 2.9 μg m-3. Chloride, Na+ and NO3- were mostly associated with PM2,5-10. Chloride deficits with respect to sea-salt Cl/Na ratio were found in both size fractions.

Determinação seletiva de tributilestanho na presença de Sn(IV) em amostras ambientais usando HG-ICP OES e Saccharomyces cerevisiae como material sorvente

A method for selective determination of tributyltin in the presence of Sn(IV) by combining hydride generation inductively coupled plasma optical emission spectrometry (HG-ICP OES) and solid phase extraction (SPE) using baker's yeast is proposed. The procedure is based on selective retention of TBT by the yeast at pH = 6. Detection limit of 1.9 µg L-1 and quantification limit of 6.3 µg L-1 were obtained. TBT and San(IV) were determined in the range of 0-25 µg L-1 and the proposed approach was applied to analyze river water, sea water and biological extracts, with recoveries of 114, 101 and 86%, respectively.

Desidratação de etanol sobre material nanoestruturado do tipo LaSBA-15

La-incorporated SBA-15 mesopourous molecular sieves (LaSBA-15) were directly synthesized with aim to convert ethanol to ethylene. The samples were characterized by XRD, XRF, nitrogen sorption and acidity, by thermodesorption of n-buthylamine. The results have indicated that all the samples have showed high ordered mesostructure with a large average pore size, and that the lanthanum incorporation has caused an increase in the acidity of the SBA-15. The LaSBA-15 samples have improved, with low deactivation rate, the conversion of the ethanol to water, ether, acetaldehyde and ethylene. In addition, they have increased the ethylene selectivity.

Eletrodos positivos tubulares para baterias chumbo ácidas produzidas com material ativo nanométrico

Conventional stationary lead acid batteries positive tubular plates have a specific capacity of about 120 Ah/kg. This value represents an active material utilization coefficient of 50%. The production of these plates includes some initial processes to generate the active PbO2 from a precursor material. In the present work it will be presented a proper and novel methodology to assemble tubular plates directely with nanometric powder of PbO2 particles. The utilization coefficient of these plates was about 80%, and they were able to endure more than 130 severe duty cycles. This high utilization coefficient is a higly desirable feature for electric vehicles batteries.

Development of Russian Ports in The Gulf of Finland

Russia has been one of the fastest developing economic areas in the world. Based on the GDP, the Russian economy grew evenly since the crisis in 1998 up till 2008. The growth in the gross domestic product has annually been some 5–10%. In 2007, the growth reached 8.1%, which is the highest figure after the 10% growth in 2000. Due to the growth of the economy and wage levels, purchasing power and consumption have been strongly increasing. The growing consumption has especially increased the imports of durables, such as passenger cars, domestic appliances and electronics. The Russian ports and infrastructure have not been able to satisfy the growing needs of exports and imports, which is why quite a large share of Russian foreign trade is going through third countries as transit transports. Finnish ports play a major role in transit transports to and from Russia. About 15% of the total value of Russian imports was transported through Finland in 2008. The economic recession that started in autumn 2008 and continues to date has had an impact on the economic development of Russia. The export income has decreased, mainly due to the reduced world market prices of energy products (oil and gas) and raw minerals. Investments have been postponed, getting credit is more difficult than before, and the ruble has weakened in relation to the euro and the dollar. The imports are decreasing remarkably, and are not forecast to reach the 2008 volumes even in 2012. The economic crisis is reflected in Finland's transit traffic. The volume of goods transported through Finland to and from Russia has decreased almost in the same proportion as the imports of goods to Russia. The biggest risk threatening the development of the Russian economy over long term is its dependence on export income from oil, gas, metals, minerals and forest products, as well as the trends of the world market prices of these products. Nevertheless, it is expected that the GDP of Russia will start to grow again in the forthcoming years due to the increased demand for energy products and raw minerals in the world. At the same time, it is obvious that the world market prices of these products will go up with the increasing demand. The increased income from exports will lead to a growth of imports, especially those of consumer goods, as the living standard of Russian citizens rises. The forecasts produced by the Russian Government concerning the economic development of Russia up till 2030 also indicate a shift in exported goods from raw materials to processed products, which together with energy products will become the main export goods of Russia. As a consequence, Russia may need export routes through third countries, which can be seen as an opportunity for increased transit transports through the ports of Finland. The ports competing with the ports of Finland for Russian foreign trade traffic are the Russian Baltic Sea ports and the ports of the Baltic countries. The strongest competitors are the Baltic Sea ports handling containers. On the Russian Baltic Sea, these ports include Saint Petersburg, Kaliningrad and, in the near future, the ports of Ust-Luga and possibly Vyborg. There are plans to develop Ust-Luga and Vyborg as modern container ports, which would become serious competitors to the Finnish ports. Russia is aiming to redirect as large a share as possible of foreign trade traffic to its own ports. The ports of Russia and the infrastructure associated with them are under constant development. On the other hand, the logistic capacity of Russia is not able to satisfy the continually growing needs of the Russian foreign trade. The capacity problem is emphasized by a structural incompatibility between the exports and imports in the Russian foreign trade. Russian exports can only use a small part of the containers brought in with imports. Problems are also caused by the difficult ice conditions and narrow waterways leading to the ports. It is predicted that Finland will maintain its position as a transit route for the Russian foreign trade, at least in the near future. The Russian foreign trade is increasing, and Russia will not be able to develop its ports in proportion with the increasing foreign trade. With the development of port capacity, cargo flows through the ports of Russia will grow. Structural changes in transit traffic are already visible. Firms are more and more relocating their production to Russia, for example as regards the assembly of cars and warehousing services. Simultaneously, an increasing part of transit cargoes are sent directly to Russia without unloading and reloading in Finland. New product groups have nevertheless been transported through Finland (textile products and tools), replacing the lost cargos. The global recession that started in autumn 2008 has influenced the volume of Russian imports and, consequently, the transit volumes of Finland, but the recession is not expected to be of long duration, and will thus only have a short-term impact on transit volumes. The Finnish infrastructure and services offered by the logistic chain should also be ready to react to the changes in imported product groups as well as to the change in Russian export products in the future. If the development plans of the Russian economy are realized, export products will be more refined, and the share of energy and raw material products will decrease. The other notable factor to be taken into consideration is the extremely fast-changing business environment in Russia. Operators in the logistic chain should be flexible enough to adapt to all kinds of changes to capitalise on business opportunities offered by the Russian foreign trade for the companies and for the transit volumes of Finnish ports, also in the future.

Remoção dos hormônios 17β-estradiol e 17α-etinilestradiol de soluções aquosas empregando turfa decomposta como material adsorvente

This paper describes the adsorption of 17β-estradiol (E2) and 17α-ethinylestradiol (EE2) from aqueous solution by decomposed peat. The peat presented a good adsorption process, close to 76.2% for E2 removal and approximately 55.0% for EE2. Moreover, the results indicated a probable multi-layered process. Adsorption isotherms were well fitted by Freundlich model. The data were evaluated considering the pseudo-first-order and pseudo-second-order approaches, being the second more significant mechanism in the rate-controlling step. Thermodynamic data revealed that hormones adsorption onto peat is spontaneous under the employed experimental conditions. The results confirmed the potential of this adsorbent to be employed for effluents treatment.

A quantitative validated method using liquid chromatography and chemometric analysis for evaluation of raw material oF Maytenus ilicifolia (Schrad.) Planch., Celastraceae

The hydroalcoholic extracts prepared from standard leaves of Maytenus ilicifolia and commercial samples of espinheira-santa were evaluated qualitatively (fingerprinting) and quantitatively. In this paper, fingerprinting chromatogram coupled with Principal Component Analysis (PCA) is described for the metabolomic analysis of standard and commercial espinheira-santa samples. The epicatechin standard was used as an external standard for the development and validation of a quantitative method for the analysis in herbal medicines using a photo diode array detector. This method has been applied for quantification of epicatechin in commercialized herbal medicines sold as espinheira-santa in Brazil and in the standard sample of M. ilicifolia.

A retórica da linguagem científica: das bases teóricas à elaboração de material didático para o ensino superior de Química

This work is part of a study that focused on analyzing the contributions of didactic activities related to scientific language rhetoric characteristics aimed at developing students' abilities to identify such characteristics in chemistry scientific texts and critical reading of those texts. In this study, we present the theoretical basis adopted to determine the scientific discourse characteristics and for the production of the didactic material used in those activities. Latour, Coracini and Campanario studies on persuasive rhetorical strategies present in scientific articles aided the production of such material.

Certified reference material to water content determination in bioethanol fuel

Bioethanol is a strategic biofuel in Brazil. Thus, a strong metrological basis for its measurements is required to ensure the quality and promote its exportation. Recently, Inmetro certified a reference material for water content in bioethanol. This paper presents the results of these studies. The characterization, homogeneity, short-term stability and long-term stability uncertainty contributions values were 0.00500, 0.0166, 0.0355 and 0.0391 mg g-1, respectively. The certificated value for water content of bioethanol fuel was (3.65 ± 0.11) mg g-1. This CRM is the first and up to now the unique in the world.

Elementos traço em material particulado atmosférico de uma região agroindustrial do sudeste do Brasil

Trace element concentrations were measured in atmospheric particulate matter collected in 2009 and 2010, in a Brazilian region influenced by pre-harvest burning of sugar cane crops. For coarse particles, high concentrations of Al, Fe, K and Ca suggested that re-suspended soil dust was the main source of aerosol trace elements, subsequently confirmed by XRD analysis. High levels of K, Zn, As, Cd and Pb were found in fine particles, confirming the contribution of biomass burning and vehicle emissions, whereas Na, Al, K, Fe and Zn were the representative elements in ultrafine particles, influenced by a diversity of sources.

Caracterização detalhada de material de referência certificado de carvão brasileiro

The use and characterization of the first Certified Reference Material (CRM) of Brazilian coal for analytical quality control are presented. All results were determined within the limits of repeatability and reproducibility allowed under the standards. Notable among the characterization parameters was the mineral matter content (45.39%) obtained by an alternative procedure showing a low relative error (-2.1%) compared to the standard technique (low ashing temperature). The possible expanded application of this CRM application in national laboratories, beyond the certificated and reference parameters, has advantages such as lower cost and easy availability, but round robin tests must be performed.

Análise exploratória rápida e não destrutiva (screening) da presença de elementos químicos tóxicos em material escolar por fluorescência de raios x

Compulsory in Brazil, toy certification aims to prevent possible risks in toy use. The Brazilian National Institute of Metrology (INMETRO) establishes the maximum concentration of toxic elements (TE) that may be present in toys. This study evaluates the presence of TE in different crayons, gouache and modeling clays using X-ray fluorescence. This technique is fast, has low operating cost and minimum sample pretreatment, resulting in a clean procedure without reagent consumption and waste generation. Bromine (in gouache) and Barium (in crayons) were the only potentially TE identified in the samples studied.