Resumo Este trabalho objetivou a preparação da zeólita ZSM-5 suportada com nanopartículas de óxido de ferro para uso como catalisador na degradação de um poluente orgânico em solução aquosa a partir do processo foto-Fenton. A zeólita foi preparada usando gel nucleante como indutor de formação da estrutura tipo MFI. Nanopartículas de óxido de ferro foram suportadas sobre a zeólita através da técnica de impregnação incipiente. Além disso, nanopartículas de óxido de ferro foram preparadas para fins de comparação entre as atividades catalíticas na reação foto-Fenton. Os materiais produzidos foram caracterizados por difração de raios X, microscopia eletrônica de varredura e análise de adsorção/dessorção de nitrogênio. Os resultados revelaram a formação do sistema Fe2O3/ZSM-5 com propriedades intrínsecas que resultaram em satisfatória atividade catalítica, sendo superior ao óxido de ferro. Além disso, esse sistema apresentou excelente atividade e estabilidade após três ciclos de reuso. O material Fe2O3/ZSM-5 produzido neste trabalho apresenta-se como um catalisador promissor para uso na reação foto-Fenton para a degradação de poluentes orgânicos em soluções aquosas.

Abstract The aim of this work was to prepare ZSM-5 zeolite-supported iron oxide nanoparticles for use as a catalyst in the degradation of an organic pollutant in aqueous solution through the photo-Fenton process. ZSM-5 zeolite was prepared using nucleation gel to induce the formation of MFI-type structure. Iron oxide nanoparticles were supported on the zeolite by incipient wetness impregnation technique. Moreover, iron oxide nanoparticles were prepared for comparison purposes of the catalytic activities in photo-Fenton reaction. The produced materials were characterized by X-ray diffraction, scanning electron microscopy, and analysis of nitrogen adsorption-desorption isotherms. The results revealed the formation of Fe2O3/ZSM-5 system containing intrinsic properties that resulted in a satisfactory catalytic activity, higher than the iron oxide. In addition, the system presented excellent activity and stability after three reuse cycles. The Fe2O3/ZSM-5 system prepared in this work is a promising catalyst for use in photo-Fenton reaction for the degradation of organic pollutants in aqueous solutions.

Resumo Aluminato de níquel (NiAl2O4) foi preparado utilizando quitosana como precursor polimérico e uma solução amoniacal como um agente de precipitação. Além disso, sais de nitrato de níquel e de nitrato alumínio foram empregados como fontes de Ni e Al, em quantidades estequiométricas (razão molar Ni:Al = 1:2). Partículas de NiAl2O4 foram preparadas em diferentes temperaturas de calcinação e as suas propriedades foram investigadas. Os sólidos sintetizados foram caracterizados por difração de raios X, espectroscopia de infravermelho, microscopia de força atômica, análise termogravimétrica e isotermas de adsorção-dessorção de nitrogênio. Os resultados mostraram que o processo de tratamento térmico influencia fortemente sobre formação da fase espinélio NiAl2O4. Partículas de aluminato de níquel, com uma estrutura porosa e com alta área superficial, foram obtidas em temperaturas superiores a 700 °C.

Abstract Nickel aluminate oxide (NiAl2O4) was prepared using chitosan as polymeric precursor and ammonia solution as a precipitating agent. In addition, nickel nitrate and aluminum nitrate salts were used as sources of Ni and Al, under stoichiometric amounts (molar ratio Ni:Al = 1:2). NiAl2O4 particles were prepared at different calcination temperatures and their properties were investigated. The synthesized materials were characterized by X-ray diffraction, infrared spectroscopy, atomic force microscopy, thermogravimetric analysis and nitrogen adsorption-desorption isotherms. The results showed that the thermal treatment process strongly influence on the formation of a single-phase structure of NiAl2O4 spinel. Nickel aluminate spinel with a porous structure and high surface area was obtained at temperatures above 700 ºC.

En este trabajo se investigó la hidrólisis enzimática de salvado de arroz por ultrasonido para obtener glucosa. Se evaluaron variables del proceso tales como la temperatura, la concentración de enzima y la humedad para la hidrólisis enzimática con y sin la aplicación de la irradiación ultrasónica. La enzima utilizada fue una mezcla de amilasa de Trichoderma reesei. Se evaluó la cinética de la hidrólisis enzimática de salvado de arroz en el período constante de la velocidad de reacción. Los mejores resultados para la hidrólisis enzimática con la aplicación de ultrasonidos fueran utilizando 3% de enzima, 60 ° C y 65% de humedad, el rendimiento obtenido fue 0,38 g de azúcar / g de salvado de arroz, mientras que el más alto rendimiento de la hidrólisis en ausencia de ultrasonido fue 0,20 g de azúcar / g de salvado de arroz utilizando 3 % de enzima, 60 ° C y 50 % de humedad. El uso de ultrasonido mejora la hidrólisis enzimática permitiendo obtener 74 % más azúcares fermentables que en la ausencia de ultrasonidos, lo que demuestra que el uso de ultrasonido es una promisora tecnología que se puede utilizar en las reacciones enzimáticas y como una alternativa de intensificación de procesos.

In this work ultrasound-assisted solid-state enzymatic hydrolysis of rice bran to obtain fermentable sugars was investigated. For this purpose, process variables such as temperature, enzyme concentration and moisture content were evaluated during the enzymatic hydrolysis with and without ultrasound irradiation. The enzyme used is a blend of amylases derived from genetically modified strains of Trichoderma reesei. Kinetic of the enzymatic hydrolysis of rice bran at the constant-reaction rate period were measured. The best results for the ultrasound-assisted enzymatic hydrolysis was obtained using 3 wt % of enzyme, 60 ºC and moisture content of 65 wt %, yielding 0.38 g sugar/g rice bran, whereas for the hydrolysis in the absence of ultrasound the highest yield was 0.20 g sugar/g rice bran using 3 wt % of enzyme, 60 ºC and moisture content of 50 wt % . The use of ultrasound-assisted enzymatic hydrolysis of rice bran was intensified, obtaining around 74 % more fermentable sugar than in the absence, showing that the use of ultrasound is a promising technology to be used in enzymatic reaction as an alternative of process intensification.

In this work, ZnAl2O4 spinel was used as photocatalyst for dye degradation in aqueous solutions under UV irradiation. This material was prepared by a route with chitosan as template. The effects of process variables, such as, initial dye concentration and photocatalyst concentration were investigated. Kinetic parameters were obtained and the reaction order was determined. The results revealed that both studied variables presented strong influence on the dye degradation efficiency, which attained 100% in some cases. It was found that the dye photocatalytic degradation under UV irradiation followed a first order kinetic behavior. The results indicated that ZnAl2O4 spinel can be used to treat dye containing effluents

This work is focused on the determination of liquid-liquid equilibrium data for systems containing methyl and ethyl fatty acid esters, water, glycerol and ethanol at temperatures of 303.15 K and 318.15 K using a near-infrared spectroscopy technique (NIR). The NIR method used in this investigation provided quite satisfactory results when compared to conventional analytical techniques and hence can be used as an advantageous tool to quantify the compounds involved in the liquid-liquid equilibrium systems: i) without previous preparation of the samples; ii) with less waste generation; iii) at low cost; and iv) via a non-destructive technique, as sample analyses are made directly, showing good reproducibility and reliability of the data. The NIR method was effective in the use of different temperatures for calibration and validation of the systems under study. Besides, it is shown that extrapolation with the technique may be possible, making LLE predictions feasible for other conditions not used in the calibration procedure.

This work investigates the influence of reaction time (ranging from 12 to 96 h) on the characteristics of zinc stannate (Zn2SnO4) nanoparticles obtained by the hydrothermal method at 200°C. The nanoparticles were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), surface area measurements (BET) and infrared spectroscopy (IR). The results showed that the reaction time influenced the properties of Zn2SnO4 nanoparticles. The product presented a pure crystalline phase with mean particle size about 20 nm and BET surface area ranging from 34 to 43 m².g-1.

In Brazil, the species Maytenus aquifolia and Maytenus ilicifolia are widely used in popular medicine in the form of teas for stomach and ulcer illness treatment. Despite the great interest in Maytenus aquifolia therapeutic properties and the fact that it is an abundant and native plant growing in Brazil, there is a lack of information in the literature concerning the extraction at high pressures. In this context, this work is focused on the mathematical modelling of the packed-bed extraction of Maytenus aquifolia with compressed CO2. Three mathematical models were used to represent the experimental data. The experiments were performed in a laboratory-scale unit, evaluating the effects of temperature (293 to 323 K), pressure (100 to 250 bar), and extraction time on the yield of the extracts. Results show that the extraction temperature and solvent density exerted a pronounced effect on yield. The mathematical model of Sovová was the most suitable to represent the experimental extraction data of M. aquifolia.

Enzymes have been extensively used in organic solvents to catalyze a variety of reactions of biological and industrial significance. In this work, the characteristics of free and immobilized inulinase were investigated in buffered solutions of butyl acetate. The influences of the organic solvent content on the optimal temperature and pH, the stabilities to temperature and pH and the kinetic parameters were systematically evaluated. The results showed that the organic solvent content had no effect on the optimal pH, either in the free or immobilized inulinase. For the immobilized enzyme, the optimal temperatures ranged from 55ºC to 60ºC, depending on the content of butyl acetate. At higher butyl acetate content, the stability of the immobilized enzyme increased for both pH and temperature. The organic solvent showed the tendency to increase the values of the kinetic parameters Km and v max for both free and immobilized inulinase.

As espécies de Maytenus ilicifolia e Maytenus aquifolia são utilizadas como antiespasmódico, contraceptivo, antiulcerogênico, diurético, cicatrizante e analgésico. A ação antiulcerogênica dos extratos de Maytenus ilicifolia possuem relação com a presença de taninos e com os triterpenos friedelan-3-ona, friedelan-3-ol e friedelin. Este trabalho está focado na determinação do teor de taninos e dos triterpenos friedelan-3-ona, friedelan-3-ol e friedelin em 15 populações nativas de Maytenus ilicifolia distribuídas nas regiões Sul e Centro-Oeste do Brasil. A correlação entre a concentração destes compostos com variáveis ambientais, tais como temperatura média anual (TMA), clima segundo Koeppen, vegetação, geomorfologia, latitude e altitude foi determinada através do emprego da correlação de Pearson. Os resultados mostraram que as variáveis temperatura média anual e clima apresentaram influência significativa ao nível de confiança de 95% sobre a concentração de taninos. O maior teor de taninos foi encontrado na população de Ponta Porã, a qual possui uma temperatura média anual de 23 °C. Para os triterpenos estudados, friedelan-3-ona, friedelan-3-ol e friedelin, não foi evidenciada correlação significativa entre a concentração destes compostos com as variáveis ambientais estudadas.

Maytenus ilicifolia and Maytenus aquifolia species are widely used as a cicatrisation agent, an anti-spasmodic, contraceptive, antiulcerogenic, diuretic and analgesic. Considering the importance of these species in popular medicine, this work is focused on the determination of the chemical content of tannins and the triterpenes friedelan-3-one, friedelan-3-ol and friedelin in 15 native populations of Maytenus ilicifolia distributed in the south and mind-west regions of Brazil. Correlation of the concentration of these compounds with the environmental parameters such as average annual temperature, climate, vegetation, geomorphology, latitude and altitude was determined using Pearson's coefficient. Results showed that average annual temperature and climate have significant effect on tannin content at a 95% confidence level. The highest tannin concentration was found in Ponta Porã population, and for the triterpenes investigated, a significant correlation between their concentrations with the environmental variables studied was not verified.

This work reports the effects of temperature (20 to 50ºC) and pressure (100 to 250 bar) on the extraction yield, chemical characteristics and antimicrobial activity of extracts of Peumus boldus Molina obtained by compressed carbon dioxide extraction. Results showed that the extraction variables affect the extraction yield and the chemical distribution of the major compounds present in the extracts. The extracts were chemically analyzed with regard to 1,8-cineole, trans-sabinene, pinocarveol, pinocarvone, 4-terpineol, ascaridole, piperitone oxide, limonene dioxide and n-eicosane in a GC/MSD. Antimicrobial tests demonstrated that the high-pressure CO2 extracts had activity against 13 bacteria and that better action was verified with extracts obtained at a lower CO2 extraction density and a higher temperature.