Corais como organismos biomonitores: aplicação, pré-tratamento e determinação de elementos majoritários e minoritários

Corals incorporate major and trace elements in their tissues and skeletons, acting as good proxies for contaminant inputs over time. This incorporation occurs by a variety of mechanisms and depends on the bioavailability of elements. Corals are very susceptible to metal contamination during sample collection. As such, pre-treatment procedures need to include a decontamination step. The high Na and Ca concentrations in the matrix make the determination of trace metals an analytical challenge. The present paper reviews all the information published on coral sample pretreatments, metal determinations in corals, and also discusses the use of coral to monitor metal contamination.

Processo UV/H2O2 como pós-tratamento para remoção de cor e polimento final em efluentes têxteis

Several problems are involved the treatment plants of textile effluents, mainly the low efficiency of color removal. This paper presents an alternative of post-treatment by UV/H2O2 process, for color removal in biologically treated textile effluents. The tests were performed in a photochemical reactor and samples were taken at different times to perform analyses. Using 250 mgH2O2.L-1, 96% removal of color was verified, indicating the dyes degradation. A reduction of 84% of aromatics compounds, 90% of TSS removal, and a further reduction of the organic fraction were observed, demonstrating that the process is effective as a post-treatment of effluents from textile industries.

Desenvolvimento de metodologia para avaliar remoção de estrogênios em estações de tratamento de esgotos

The present research aimed to study the parameters that affect the determination of estrogens in sewage upon the use of SPE and determination by using gas chromatography mass spectrometry (GC/MS). The study evaluated the stabilization pond technology with regard to estrogens removal. The results showed that the methodology was able to identify and quantify the estrogens E1, E2, E2-17A and EE2 in sewage. Moreover, the estrogens sometimes were not removed in the stabilization pond, showing that even the high hydraulic retention time (HRT) and high sunlight intensity were not enough to degrade these compounds completely during load peaks.

Determinação do teor de cálcio em comprimido à base de lactato de cálcio utilizado no tratamento da osteoporose

The present study utilized thermogravimetry (TG) and optical emission spectrometry with inductively coupled plasma (ICP/OES) to determine the amount of calcium in calcium lactate tablets used in the treatment of osteoporosis. Thermogravimetry results indicated that the decomposition temperature of CaCO3 occurred at 603.9 and 609.4 ºC in the samples of calcium lactate and tablets, respectively. The calcium content obtained by TG for the tablets sample showed a similar result to that disclosed by ICP-OES, indicating a value of 8.93% for both techniques.

Efeito do teor de umidade sobre o pré-tratamento a vapor e a hidrólise enzimática do bagaço de cana-de-açúcar

The effect of moisture content in the steam treatment and enzymatic hydrolysis of sugarcane bagasse was evaluated. Steam treatment was perfomed at 195-210 ºC for 4-8 min using cane bagasse with moisture contents in the range 16-100 wt% (dry basis). Increased moisture contents not only had a positive influence in recovery of main cane biomass components but also resulted in better substrates for enzymatic hydrolysis. As a result, drying is not required for optimal pretreatment and enzymatic hydrolysis of sugarcane bagasse, which can be processed into second generation ethanol immediately after crushing and hot water washing.

Uso de materiais recicláveis na determinação gravimétrica de CO2 no ar ambiente e tratamento dos resíduos de laboratório gerados

An alternative system was tested for the determination of CO2 in air using recyclable materials. The results indicate that the proposed system allows for reliable, accurate, robust and efficient collection, comparable to the standard gravimetric method. Laboratory wastes are easily treated using a filtrate that can be discharged into the sewer and solids that can be reused. The proposed system is a simple and low-cost tool that encompasses important aspects of environmental education, which should be part of the education in chemistry of undergraduate students and technicians.

Emissões de óxido nitroso do tanque de aeração de uma estação de tratamento de esgotos com sistema de lodos ativados convencional

Nitrous oxide (N2O) emissions were measured monthly from January to June 2010 in the aeration tank of a wastewater treatment plant (WWTP) in Southeast Brazil. Emissions were lower in summer than winter and were positively related with influent ammonium (NH4+) concentration. The average N2O emission was 1.11 kg N day-1 corresponding to 0.02% of the influent total nitrogen load. The average emission factor calculated for the population served was 2.5 lower than that proposed by the Intergovernmental Panel on Climate Change (IPCC) for inventories of N2O emissions from WWTPs with controlled nitrification and denitrification processes.

Otimização do pré-tratamento hidrotérmico da palha de cana-de-açúcar visando à produção de etanol celulósico

The sugarcane industry has huge potential for biorefinery concept application, given its development in recent years. In this context, cane sugar straw has become an attractive raw material for biofuel production. This study aims to investigate the chemical composition of cane sugar straw from different regions of Brazil, and to optimize a hydrothermal pretreatment stage for cellulosic ethanol production. Results of chemical characterization of the cane sugar straw for the regions assessed indicated little influence of place on straw chemical composition. Hydrothermal pretreatment showed high efficiency in hemicellulose removal. Hydrothermal pretreatments operating with temperatures of 190 and 210 ºC presented satisfactory results, reaching values close to 100% hydrolysis.

Tratamento de dados censurados em estudos ambientais

Due to the inherent limitations of the analytical methods of measurement, environmental exposure data often present observations described as below a certain detection limit, also called left-censored data. Censored data directly interferes in almost all types of statistical analyzes, including descriptive parameters, hypothesis testing, confidence intervals, correlations and regressions. In this work, we investigated the performance of the main classes of methods from major publications available in the literature, considering their advantages and limitations. Some criteria for selecting the best method of dealing with censored data are presented.

Aplicação da radiação ultravioleta como forma de contribuição para a química verde e construção de um reator fotoquímico alternativo e de baixo custo, para pré-tratamento de amostras

Ultraviolet radiation corresponds to a fraction of electromagnetic radiation, covering wavelengths between 1 and 400 nm. Methods based on UV irradiation have become popular because it is possible to treat samples simply by applying energy, avoiding procedures that require the use of toxic substances, thus contributing to the development of Green Chemistry. This study aimed to assess the main applications of UV radiation reported in the literature and thoroughly described the construction of an alternative and low-cost photochemical reactor to be used for the pretreatment of samples in the laboratory. The use of this new photochemical reactor in the clean-up of milk samples for spectrofluorimetric measurements was also reported.

Avaliação da eficiência de degradação de hidrocarbonetos aromáticos por bactérias provinientes de estação de tratamento de efluente de refinaria de petróleo

Three bacterial strains were isolated from the activated sludge system of petroleum refinery wastewater, identified by partial sequencing of 16S rDNA, and classified as Acinetobacter genomospecies 3, Bacillus pumilus, and Bacillus flexus. The degradation efficiency of aromatic hydrocarbons was evaluated by gas chromatography with a flame ionization detector. In a mineral medium containing anthracene and phenanthrene and the consortium of microorganisms, the removal efficiency was 96% and 99%, respectively, after 30 days. The good rate of hydrocarbon degradation proves the operational efficiency of the microbial consortium in treating effluents containing these compounds.

INFLUÊNCIA DO TRATAMENTO TÉRMICO NO NANOCOMPÓSITO FOTOCATALISADOR ZnO/TiO2

ZnO/TiO2 nanocomposites were prepared by impregnating zinc acetate dihydrate on the surface of titanium dioxide P25, followed by thermal treatment at 350, 600, 750, and 900 °C, in order to investigate the TiO2 phase and titanate formation and the role of the latter in the photocatalytic activity of the nanocomposite. In the nanocomposites, the anatase-to-rutile transition is favored due to the presence of Zn2+, and the conversion is nearly complete at 750 °C. The presence of zinc metatitanate in the sample heated at 600 °C had no significant effect on the nanocomposite photocatalytic activity.

DOENÇA DE ALZHEIMER: HIPÓTESES ETIOLÓGICAS E PERSPECTIVAS DE TRATAMENTO

With the increase in life expectancy registered in the past few decades, the prevalence of various medical conditions related to aging has been observed, such as dementia and related neurodegenerative conditions. The number of patients afflicted with these conditions is expected to significantly increase in the coming years. The growing social impact of dementia underlines the need for research aimed at identifying and better understanding this type of condition. Among neurodegenerative diseases, amyloidogenic diseases, in particular Alzheimer's disease (AD), are currently the most common form of dementia. Over the years, several hypotheses have been raised regarding the etiology of AD, such as the cholinergic, glutamatergic, amyloid cascade, oligomeric, metallic and diabetes type 3 hypotheses. Unfortunately, no cure is yet available for this disease, only drugs that aid in controlling the symptoms. This review article conducts a comprehensive approach of the main etiological hypotheses of AD, as well as the treatment prospects associated with each hypothesis.

TRATAMENTO DA VINHAÇA POR ADSORÇÃO EM CARVÃO DE BAGAÇO DE CANA-DE-AÇÚCAR

The aim of this study was to develop an effective and economically viable technology for the treatment of vinasse, prior to its disposal in the soil for fertirrigation, aiming this way at reducing the environmental impacts generated by inadequately discarding this effluent. The primary treatment of vinasse by adsorption was evaluated. Adsorbents were prepared from sugar cane bagasse and their efficiency evaluated in relation to the treatment of vinasse. The process of preparation of activated carbon consisted of carbonizing bagasse at different temperatures followed by chemical activation with NaOH. The carbon samples obtained by solely carbonizing sugar cane bagasse were more efficient for removing turbidity of vinasse than samples activated with NaOH. The sample carbonized at 800 °C was the most efficient for removing turbidity of wastewater (83%). During a process of adsorption of vinasse in two stages, it was possible to obtain color removal, turbidity and COD of approximately 76, 85 and 69%, respectively. After the adsorption step of vinasse, the solid waste generated in the second stage of adsorption can be burned in the boilers of the power plant itself, affording an energy of 4606 cal g-1.

Controle da ferrugem da folha e da mancha bronzeada da folha de trigo pelo uso de fungicidas em tratamento de sementes

The control of leaf rust and tan spot of wheat by seed treatment with fungicides was evaluated during 1998 in Passo Fundo, RS. Except for treatments including triadimenol and iprodione, leaf rust and tan spot severity in above ground parts of wheat plants was drastically reduced by the fluquinconazole fungicide used.