ABSTRACT The use of nanoparticles appears to be a feasible option for improving the quality of a range of wood-based products. Studies show that they can improve both the physical and mechanical properties of wood and wood-based products. This preliminary study aimed to analyze the influence of SiO2 nanoparticles on the physical and mechanical properties of wood particleboard. To this end that, panels were produced without the addition of SiO2 nanoparticles and with the addition of 4% by mass of the urea formaldehyde adhesive used for its production. The results showed that panels produced with the nanoparticles 42% reduction in thickness swelling of the panel. Therefore, the dimensional stability of the panels without decreasing mechanical properties, even when used in small proportions.

Resumo: O presente trabalho avaliou a qualidade da água em corpos hídricos urbanos utilizando técnicas estatísticas multivariadas. Na cidade de Sorocaba, SP, Brasil, foram selecionados dez corpos hídricos, e foram quantificadas nove variáveis limnológicas. Os resultados indicaram impactos devido ao descarte irregular de resíduos sólidos e esgoto doméstico. Diante dos resultados, são apresentadas diretrizes de gestão ambiental.

Abstract: The present study evaluated the water quality in urban water bodies using multivariate statistical techniques. In Sorocaba, São Paulo, ten water bodies were sampled and nine limnological variables were quantified. Irregular disposal of domestic waste and sewage was identified as impacting. Environmental management guidelines are presented.

Resumen: El presente trabajo evaluó la calidad del agua en cuerpos hídricos urbanos utilizando técnicas estadísticas multivariadas. En Sorocaba, SP, se muestreó agua de diez cuerpos hídricos y fueron cuantificados nueve variables limnológicas. Se identificó como impactantes el descarte irregular de residuos y alcantarillado domésticos. Se presentan directrices de gestión ambiental.

ABSTRACT The efficient use of biomass as fuel requires prior knowledge of the composition and properties of the material in order to be able to develop technologies for its efficient combustion while ensuring that emissions of pollutants remain within acceptable limits. Therefore, the analysis of the physical and chemical properties of these materials is essential in order to evaluate their potential for energy purposes. Given the need for improved understanding of biofuels, this study aimed to characterize biomass waste obtained from the manufacturing process of wood panels and urban waste for the production of solid biofuels. Biomass wastes were characterized in terms of their physical and chemical properties. Wastes that presented the poorest qualities for use as fuels were eucalyptus bark, industrial waste, and sweepings, which had high ash contents and low calorific values. The remaining wastes showed satisfactory characteristics for use as solid biofuels.

The contamination of natural environments by trace metals has several adverse effects on human health, which is mainly due to the high toxicity, persistence and reactivity of these species in the environment. To understand the bioavailability of trace metals, it is necessary to know the speciation in equilibrium and the dynamic behavior of the system. In this context, the present work aims to present a bibliographic review about the potentialities of the Stripping Chronopotentiometry (SCP) and Stripping Chronopotentiometry at Scanned Deposition Potential (SSCP) in the study of dynamic trace metal speciation. These techniques have low detection limits and do not suffer interference due to the adsorption of organic matter on the surface of the working electrode. Coupling these techniques with the Absence of Gradients and Nernstian Equilibrium Stripping (AGNES) enables simultaneous determination of free ions, complexation equilibrium constants and diffusion coefficients of the complexes, thus providing information on the dynamic and heterogeneity of the metal complexes in the presence of macromolecules or particles. In this paper we will present the theory of dynamic speciation of trace metals, a detailed description of how to use the techniques to obtain this information, and examples of application in model systems and natural samples.

O objetivo deste trabalho foi avaliar os processos de adsorção e dessorção de micronutrientes em amostras de turfas tropicais visando uma possível aplicação em solos. Para isso, experimentos de adsorção foram estudados em diferentes valores de pH e a partir de solução metálica multielementar e elementar. As capacidades de adsorção máximas ocorreram em pH 6,0 e a ordem de afinidade observada em geral foi: Cu > Fe > Co > Ni > Zn = Mn. A liberação dos micronutrientes foi avaliada sob diferentes valores de pH em meio aquoso, e posteriormente, em solo e planta. Os experimentos de liberação mostraram que os micronutrientes são liberados preferencialmente em pH 6,0 e na seguinte ordem: Fe > Zn > Mn > Co = Ni > Cu. A liberação dos micronutrientes para o solo é acompanhada pela sorção dos mesmos pela planta. Desta maneira, a aplicação de turfas tropicais enriquecidas com micronutrientes pode contribuir para uma maior produtividade agrícola uma vez que a liberação dos micronutrientes mostrou-se eficiente no desenvolvimento das plantas.

The objective of this work was to evaluate the adsorption and desorption of micronutrients in tropical peats, from the perspective of potential agricultural applications. Adsorption experiments were performed at different pH values, using solutions containing individual and multiple metal ions. Maximum adsorption capacity occurred at pH 6.0, and the order of affinity was Cu > Fe > Co > Ni > Zn = Mn. Release of the micronutrients was evaluated at different pH values, using an aqueous medium as well as soil and plants. Release of the micronutrients was most efficient at pH 6.0, and followed the order: Fe > Zn > Mn > Co = Ni > Cu. Micronutrient release to the soil was accompanied by uptake by the plant. The use of tropical peat enriched with micronutrients could contribute to improved agricultural productivity, since the release profile of the micronutrients can effectively stimulate plant growth.

O objetivo deste trabalho foi estudar a adsorção de micronutrientes em humina e verificar a capacidade de liberação desses elementos em água. O primeiro passo foi determinar a capacidade de adsorção da humina para alguns micronutrientes essenciais para as plantas e determinar alguns parâmetros cinéticos. A ordem de adsorção foi Zn < Ni < Co < Mn < Mo < Cu < Fe, sendo que Zn apresentou valores máximos de ca. 2,5 mg g-1 e Fe valores de ca. 0,5 mg g-1, para os sistemas contendo 1 g de humina. O ferro apresentou maiores percentuais de liberação (ca. 100%) e Co apresentou percentuais mais baixos (0,14%). Infere-se a partir dos resultados que o uso de humina enriquecida com micronutrientes pode ser uma alternativa promissora para a fertilização de solos agrícolas, com o benefício adicional de incorporar a matéria orgânica presente na forma de substâncias húmicas no solo e melhorar a produtividade agrícola.

The objective of this work was to investigate the adsorption of micronutrients in humin and to verify the ability to release these elements in water. The first step was to determine the adsorption capacity of humin for several essential plant micronutrients and check the kinetic parameters. The order of adsorption was Zn < Ni < Co < Mn < Mo < Cu < Fe, whereas Zn showed maximum values of ca. 2.5 mg g-1 and Fe values of ca. 0.5 mg g-1 for systems containing 1 g of humin. Iron presented higher percentages of release (ca. 100%) and Co the lowest percentages (0.14%). The findings suggested that the use of humin enriched with micronutrients can be a promising alternative for the fertilization of agricultural soils, with the additional benefit of incorporating organic matter present in the form of humic substances into the soil and improving the agricultural productivity.

Interações entre substâncias húmicas aquáticas (SHA), de rios tropicais, e dois interferentes endócrinos (IE) foram estudados utilizando sistema de ultrafiltração em fluxo tangencial equipado com membrana de celulose de 1 kDa com a finalidade de separar os IE livres da fração ligada as SHA. A quantificação de 17α-etinilestradiol e bisfenol A foi realizada utilizando cromatógrafo a gás acoplado a espectrômetro de massas (GC-MS). O tempo de equilíbrio entre as SHA e IE foi de aproximadamente 30 min, e as capacidades complexantes do 17α-etinilestradiol e bisfenol A foram em torno de 18,53 e 2,07 mg g-1 de carbono orgânico total (COT), respectivamente. A maior interação das SHA ocorreu para 17α-etinilestradiol, em relação ao bisfenol A, devido a presença de hidrogênio na estrutura do 17α-etinilestradiol, que podem interagir com os grupos oxigenados presentes nas SHA. Os resultados indicam que as SHA podem influenciar fortemente no transporte e reatividade dos interferentes endócrinos presentes em sistemas aquáticos

Interactions between two endocrine disruptors (ED) and aquatic humic substances (AHS) from tropical rivers were studied using an ultrafiltration system equipped with a 1 kDa cut-off cellulose membrane to separate free ED from the fraction bound in the AHS. Quantification of 17α-ethynylestradiol and bisphenol A was performed using gas chromatography-mass spectrometry (GC-MS). The times required for establishment of equilibrium between the AHS and the ED were ca. 30 min, and complexation capacities for 17α-ethynylestradiol and bisphenol A were 18.53 and 2.07 mg g-1 TOC, respectively. The greater interaction of AHS with 17α-ethynylestradiol, compared to bisphenol A, was due to the presence of hydrogen in the structure of 17α-ethynylestradiol, which could interact with ionized oxygenated groups of the AHS. The results indicate that AHS can strongly influence the transport and reactivity of endocrine disruptors in aquatic systems.

The knowledge of the structure characteristic of the Organic Matter is important for the understanding of the natural process. In this context aquatic humic substances (principal fraction) were isolated from water sample collected from the two distinct rivers, using procedure recommended for International Humic Substances Society and characterized by elemental analysis, electron paramagnetic resonance and nuclear magnetic resonance (13C NMR). The results were interpreted using principal component analysis (PCA) and the statistical analyses showed different in the structural characteristics of the aquatic humic substances studied.

Cellulose acetate polymeric membranes had been prepared by a procedure of two steps, combining the method of phase inversion and the technique of hydrolysis-deposition. The first step was the preparation of the membrane, and together was organomodified with tetraethylortosilicate and 3-aminopropyltrietoxysilane. Parameters that exert influence in the complexation of the metallic ion, as pH, time of complexation, metal concentration, had been studied in laboratory using tests of metal removal. The membranes had presented resistance mechanics and reactivity to cations, being able to be an alternative for the removal, daily pay-concentration or in the study of the lability of metals complexed.

In this work commercial filters papers were organomodified with tetraethylorthosilicate (TEOS) and 3-aminopropyltriethoxysilane (3-APTS), aiming at the development of a new analytical procedure for in-situ speciation of labile and inert metal species in aquatic systems. Parameters that exert influence on the metal lability such as pH, chelating time, concentration and characteristics of the organic matter were studied in the laboratory using tests for metal recuperation. The results showed slower kinetics for Cu ion than for Ni, Mn and Cd in the absence of aquatic humic substances (AHS). The relative lability observed for complexed metals in aquatic humic substances using organomodified filter papers was Cu>>Cd>Ni>Mn. The pH values, structural characteristics and concentration of AHS exert strong influence on the lability of the metals. The results obtained showed that the utilization of organomodified filter papers can be an interesting and promising alternative for in situ characterization of metal lability in aquatic systems.