In the face of environmental changes concerns, the study of climate change becomes essential to understand the life trajectory of planet earth. For this purpose, this work seeks to understand climate change and fluctuations in the amount of atmospheric oxygen across geological ages, carbonizing the Araucaria columnaris wood in varying oxygen concentrations, and comparing them to the fossil coal from Quiteria Outcrop. In this study, pyrolysis of Araucaria columnaris wood occurred with the use of TGA, under an atmosphere of 21% and 30% O2, analyzed in FTIR, distinguishing the constituent compounds of the wood. Multivariate analysis of the mains components (PCA) was applied, for data crossing. There is a distinction between carbonized wood and fossil charcoal, the charcoal burning temperature as well as the atmospheric oxygen composition being inconclusive. However, FTIR results indicate that the amount of oxygen has an influence on the degradation of the wood, and samples at 450 °C have greater similarities with fresh wood. Thus, it was observed that the temperature and the burning time are the main factors of the fires, being that the amount of oxygen available in the atmosphere influences the firing process.

This work describes the superficial modification of Ti/TiO2 nanotubes by copper oxide electrochemical deposition, in different temperatures (25 and 65 ºC), and its application on the photoelectrocatalytic conversion of CO2 and biogas in products of energy interest. The different temperatures deposition resulted in the formation of different geometric forms on the surface of Ti/TiO2 nanotubes and in different photoelectrocatalytic activities. The photoelectrocatalytic conversion in 0.1 mol L-1 Na2SO4 with application of -0.1 V and UV irradiation resulted in the formation of acetone and methanol from CO2 and acetone and ethanol from biogas, being that the acetone production was higher for the semiconductor synthesized at 65 ºC, while the methanol and ethanol production was higher for the semiconductor at 25 ºC. The different characteristics observed, as well as the preferential formation of different products of photoelectrocatalytic reactions for semiconductors synthesized with different electrochemical deposition temperatures are discussed.

ABSTRACT Charcoal is widely accepted as evidence of the occurrence of palaeo-wildfire. Although fossil charcoal remains have been used in many studies, investigation into the anatomical changes occurring during charring are few. The present study analyses changes in selected anatomical characters during artificial charring of modern wood of three species of the genus Araucaria (i.e. Araucaria angustifolia, Araucaria bidwillii and Araucaria columnaris). Wood samples of the studied species was charred under controlled conditions at varying temperatures. Measurements of anatomical features of uncharred wood and artificial charcoal were statistically analysed. The anatomical changes were statistically correlated with charring temperatures and most of the parameters showed marked decreases with increasing charring temperature. Compared to the intrinsic variability in anatomical features, both within and between growth rings of an individual plant, the changes induced by temperature account only for a comparatively small percentage of the observed variability. Regarding Araucaria charcoal, it seems possible that at least general taxonomic and palaeoenvironmental implications can be drawn from such material. However, it is not clear so far whether these results and interpretations based on only three taxa, can be generalized for the entire family and anatomically similar fossil taxa or not.

The aim of the study is to evaluate the physical and chemical changes that occur on wood fragments submitted to different temperatures, verifying their influence on significant chemical characteristics in the forming process. Carbonization process in muffle associated to the techniques of Thermogravimetry, Fourier Transform Infrared Spectroscopy (FTIR) and multivariate analysis. The analyses were performed on 3 replicates for each burn temperature. The temperature of the thermal muffle process was in every 50 °C, from 200 °C to 600 °C. TGA were performed under nitrogen atmosphere, using a heating ramp from 25 °C min-1 to 995 °C. A range between 1900 to 650 cm-1 was used, with a resolution of 4 cm-1 and 64 scans. The PCA showed that it is possible to describe 95.73% of the data, grouping the samples into three main clusters. These clusters were used to build a SIMCA (Soft Independent Modeling of Class Analogy) model, enabling to predict with 100%. Results showed that technical associations, such as TGA, FTIR and multivariate analysis may help to characterize the natural carbonization process and, in future works, contribute to significant (paleo)environmental inferences.

ABSTRACT A new modified electrode for indirect sensing of OH· and radical scavengers was described. The electrochemical polymerization of methylene blue in aqueous solutions and the properties of the resulting films on a glassy carbon electrode were carried out using cyclic voltammetry. A surface coverage of 1.11 × 109mol cm2 was obtained, revealing a complete surface coverage of the polymeric film on the electrode surface. OH· was able to destroy the poly(methylene blue) film by exposure to a Fenton solution. The loss of the electrochemical signal of the residual polymeric film attached to the electrode surface was related to the extent of its dissolution. The applicability of the sensor was demonstrated by evaluating the OH radical scavenging effect on different concentrations of ascorbic acid. The obtained radical scavenging capacity were 31.4%, 55.7%, 98.9% and 65.7% for the ascorbic acid concentrations of 5, 10, 30 and 50 mM, respectively.

The dyeing agate employs large quantities of potentially harmful wastewater to the environment, such as, effluent with chromium and nitrate ions. The aim of the present study was investigate the electrodialysis technique efficiency in the removal of contaminant ions present in wastewater generated by the agate dyeing industry and evaluate the toxicity of the effluent studied. The electrodialysis experiments were performed in acrylic cell 5 compartments separated by ion selective membranes and fitted with a 70TiO2/30RuO2 DSA® anode and a titanium plate as cathode. After application of the electrodialysis treatment, toxicity of the effluent was evaluated in two different trophic levels, Artemia salina and Lactuca sativa. The results indicated the removal of 233.3 mg L-1 of nitrate and 223.6 mg L-1 of chromium was extracted, in flow mode. The toxicity tests showed a tendency to decrease the percentage of mortality of organisms after application of the electrodialysis technique. Thus, it concludes that the electrodialysis is an effective method for treating effluents containing metal ions, and is possible reuse the recovered solutions in the dyeing process.

Resumo A contaminação de hortaliças por micro-organismos patogênicos está diretamente relacionada com a qualidade das águas de irrigação utilizadas na agricultura e com o solo onde se encontram. Com o objetivo de se verificar as condições empregadas na produção de alface (Lactuca sativa L.) em três pequenas propriedades do interior do Rio Grande do Sul (Brasil), foram avaliadas a condição físico-química das águas de irrigação, e a condição microbiológica das águas, solo e folhas de alface. As análises bacteriológicas das águas de irrigação, hortaliças e do solo foram realizadas usando a técnica dos tubos múltiplos ou por contagem em placa, e levou em conta os coliformes totais, coliformes termotolerantes, e presença ou ausência de Escherichia coli, Salmonella sp. e Listeria sp.. As análises físico-químicas realizadas nas águas de irrigação foram pH, turbidez, oxigênio dissolvido, demanda bioquímica de oxigênio, carbono orgânico total e nitrogênio total. As análises bacteriológicas nas águas de irrigação indicaram a ausência de Salmonella sp. e Listeria sp.. Entretanto, foi detectada a presença de E. coli e valores acima do permitido pela legislação para coliformes termotolerantes. Desta forma, estas águas se encontram fora dos padrões estabelecidos pela Resolução CONAMA n° 357. A pesquisa também mostrou a presença de E. coli, Salmonella sp. e Listeria sp. nas hortaliças irrigadas, sugerindo que a fonte de contaminação por Salmonella sp. e Listeria sp. deve ser a partir do solo, e não a partir da água de irrigação. Os dados físico-químicos mostraram que apenas uma das propriedades analisadas apresentou todos os parâmetros adequados, segundo a legislação vigente para águas doces de classe 1. Portanto, apenas uma das propriedades apresentou condições físico-químicas para ser utilizada na irrigação de alface, embora nenhuma tenha apresentado condições higiênico-sanitárias para tal uso.

Abstract The contamination of greenery by pathogenic microorganisms is directly related to the quality of irrigation water used in agriculture and to the soil where the greenery is located. In order to verify the conditions surrounding lettuce (Lactuca sativa L.) production at three small properties of Rio Grande do Sul State, Brazil, we evaluated the physico-chemical conditions of irrigation water as well as the microbiological condition of water, soil and lettuce leaves. Bacteriological analyses of the irrigation water, greenery and soil were performed using the multiple tubes or plate-counting techniques, and the total coliforms, thermo-tolerant coliforms, and presence or absence of Escherichia coli, Salmonella sp. and Listeria sp. was evaluated. The irrigation water was analyzed to determine pH, turbidity, dissolved oxygen, biochemical oxygen demand, total organic carbon and total nitrogen. Bacteriological analysis on the irrigation water indicated the absence of Salmonella sp. and Listeria sp.. However, we detected the presence of E. coli and higher thermo-tolerant coliform levels than that established by current legislation. Thus, these water samples do not conform to the standards established by the CONAMA n° 357 Resolution. Our analyses also showed the presence of E. coli, Salmonella sp. e Listeria sp. on the irrigated greenery, suggesting that the source of the Salmonella sp. and Listeria sp. contamination must be the soil, rather than the irrigation water. Physico-chemical analyses showed that only one of the analyzed properties conforms to the standards established by current legislation for Class 1 fresh water. Therefore, only one of the properties presented the physico-chemical conditions appropriate for lettuce irrigation, although no property presented hygienic sanitary conditions for such use.

Iontophoresis is a method of administering substances through the skin, which uses electrical current or potential to promote transdermal delivery. We focused on α-tocopherol (vitamin E), a natural antioxidant able to reduce or block the oxidation reactions induced by free radicals in biological membranes. The aim of this study was to perform electrochemical evaluation and analysis of vertical diffusion of gel + α-tocopherol undergoing iontophoresis. The results showed a reduction in peak current at 0.78 V of α-tocopherol molecules when subjected to iontophoresis, increasing the diffusion and degradation of the system.

Currently, the physiotherapists use the phonoforesis, which consists in the therapeutical ultrasound (US) used to increase the drug molecules migration through the skin, however, the US can shows oxidative effects, and is used, for example, in chemical reactions acceleration. The present study aimed to perform the electrochemical evaluation and the diffusion investigation of gel/caffeine 5% solutions submitted to therapeutical US (continuous mode, 1.0 W cm-2 and 1 MHz). It this study, it has been verified diffusion increase and a possible oxidation of the caffeine molecules, when subjected to therapeutical US.

Food industries employ a lot of synthetic dyes in their products. Most of these dyes are very stable face to the conventional treatments. This work studied the use of advanced oxidation process (AOP) as an alternative to the conventional ones to degrade a synthetic food effluent (photolysis and UV/H2O2 in continuous reactor). The more efficient process was the UV/H2O2 and it presented decoloration and degradation energetic efficiency values equal to 30.775 kWh m-3 and 269.909 kWh m-3, respectively. The color reduction was 96.4% and COD decrease was 38.56%.

Neste trabalho foi realizado o estudo da degradação fotoquímica do corante vermelho bordeaux. O estudo objetivou a avaliação de tratamentos alternativos com vistas à aplicação de tecnologias limpas. Os experimentos de fotodegradação foram realizados através da incidência de radiação UV em um compartimento contendo o corante (solução). O tratamento fotoquímico reduziu em 99% a coloração e a concentração da solução contendo o corante vermelho bordeaux.

This paper studied the photochemical degradation of food dye (red dye). The investigation aimed at the assessment of alternative treatments, focusing the use of clean technologies. The photochemical degradation experiments were performed in a compartment with UV radiation (mercury lamp - 250W). The photochemical treatment showed a 99% color and concentration reduction in the dye solution.