Nanocompósitos com atividade antioxidante de amido de milho/isolado proteico de soro de leite/ óleo essencial de alecrim obtidos por extrusão termoplástica

In order to improve the quality and safety of food, the active packaging emerges as a new technology based on the release of composites beneficial to food products. Thus, biodegradable films incorporated with active substances have the function of acting as a barrier to external elements, protecting the product and increasing its shelf life. They are formulated from proteins, polysaccharides, lipids or from the combination of these compounds. However, there is a need to improve the performance properties of these packages. Nanotechnologies, then, emerges with the study of many nanoparticles as additives to modify the performance of biodegradable polymers. With this, we aimed at developing and active antioxidant film of corn starch blenders and whey protein isolate with rosemary essential oil or microcapsules of rosemary essential oil reinforced with sodium montmorillonite (MMTNa + ) nanoparticles by extrusion. The films were developed and characterized in a first stage for the selection of the best polymeric blender using the following analyses: water vapor permeability (WVP), machanical properties; optical, thermogravimetry (TG), differential scanning calorimetry (DSC), x-ray diffraction (XRD) and scanning electron microscopy (SEM). In the second stage, montmorillonite clay nanoparticles and rosemary essential oil were added as reinforcement to evaluate its antioxidant effect. In a third stage, we studied the addition of microcapsules of rosemary essential oil (MR) as a form of protecting the active agent and its antioxidant potential in the films. The results indicate that the development of p olymeric blender with 30% of corn starch substitution is the most indicated for future work. The addition of rosemary essential oil or microcapsule of rosemary essential oil allowed for the obtaining of nanocomposites with antioxidant potential for application in food packages.

Obtenção de fotocatalisadores magnéticos a partir de resíduos industriais e TiO2 para a degradação de contaminantes orgânicos

In this work, magnetic photocatalysts were synthesized containing differents levels of TiO2 (40, 60 e 80%) supported at the supporter of C/LV, forming the photocatalysts 40, 60, 80Ti/C/LV, using tar pitch as carbon (C) source and red mud (LV) as iron source. The prepared magnetic photocatalysts and TiO2 were used to degrade the Remazol Black textile dye (PR5) and the organic material present in samples of a textile dye effluent. The characterization of photocatalysts by Raman, X-Ray Diffraction, Transmission Electron Micoscope and Scanning, Energy Dispersive X-ray Spectrometry, Termogravimetry and Elemental Analysis, confirms the presence of carbon and magnetite in support C/LV and the presence of TiO2 in prepared photocatalysts. The photocatalytic reactions with TiO2 were analyzed by different experimental conditions, such as: mass of TiO2 (30-240 mg), solution pH (2-10), light intensity (0.871 and 1.20 mWcm-2), type of radiation (UV and sunlight-1.420 mWcm-2), radiation incidence area (44.2 to 143.1 cm2) and dissolved oxygen (OD, 1.9 and 7.6 mg L- 1). Results showed that reactions with the following conditions: 220 mg of TiO2, pH 10, solar radiation, 7.6 mg L-1 of OD and an incidence area of radiation of 143.1 cm2 showed the best results for degradation of PR5 dye. Photocatalytic reactions with magnetic photocatalysts for degrading PR5 shows that efficiency increases with TiO2 content in the C/LV support, where, above 60% of TiO2, there was not significant increase in reaction velocity. In addition, solar radiation has proved to be advantageous for photocatalytic reactions. In order to verify the presence of a non-magnetic fraction in the photocatalyst 60Ti/C/LV0, magnetic separation was proceeded. The characterizations of the magnetic (FM) and nonmagnetic (NMF) fraction confirmed that about 25% of TiO2 did not fixed in 60Ti/C/LV photocatalyst. Results of photocatalytic reactions with FM and FNM showed that both phases have photocatalytic activity for degradation of PR5. The reactions executed for the degradation of organic matter present in the actual sample of textile effluent showed that TiO2 and magnetic photocatalyst 60Ti/C/ LV have better results for color removal (85 to 35%), soluble solids ( 11 and 3%), DQO (90 and 86%) and turbidity (94 and 11%) than the treatment done by the textile industry. Sedimentation kinetics tests in presence of a magnet showed that photocatalysts are separated faster from aqueous environment than pure TiO2. Obtained results showed that magnetic photocatalysts have excellent photocatalytic activity and can be separated from the reaction environment on a simple and quick way when a magnetic field is applied.

Síntese e aplicação de catalisadores à base de óxidos de cério, tungstênio e HZSM-5 para a produção do biodiesel

This work presents a study on the production of biodiesel by esterification reaction of oleic acid with methanol using batch reactor and different catalysts based on CeO2 and WO3 and HZSM-5. Acid treatment was performed in order to increase the catalytic activity. Different characterization techniques were performed, among them X-ray diffraction (XRD), Thermogravimetric analysis TGA/DTA, Spectroscopy in the Region in Fourier Transform Infrared (FTIR) and X-ray fluorescence (XRF). The effects of independent variables: temperature, molar ratio of oil: alcohol and the amount of catalyst and their interactions on the dependent variable (conversion of oleic acid to the corresponding ester). Overall, through the results obtained in the characterization was observed that the applied treatments were efficient, however the XRF technique, indicated that tungsten oxide leaching could occur during the preparation of the materials. The treatments performed on HZSM-5 caused no significant changes in the structure indicating that the zeolite was quite resistant to the treatments used. It was evaluated using complete 23 factorial design. For the catalysts investigated, the best reaction conditions were obtained when using higher levels of the independent variables temperature and amount of catalyst. However, for the variable molar ratio the lowest level showed significant yields for most of the synthesized catalyst, obtaining maximum conversion to the OC (67.97%), OW (74.37%), HZSM-5 (61.16%) OC-OW 1 (75.93%), OC-OW 2 (82.57%), OC-OW 3 (79.15%), S/OC-OW 1 (86.90%), S/OC-OW 2 (91.04%), S/OC-OW 3 (88.60%), S/OC-OW/H 1 (92.34%), S/OC-OW/H 2 (100%) and S/OC-OW/H 3 (98.16%). According to the experimental design, the temperature has the biggest influence on the reaction variable for all the synthesized catalysts. Among the catalysts investigated S/OC-OW/H 2 e S/OC-OW/H 3 were more effective. Reuse tests showed that the catalyst activity decreased after each cycle, indicating that the regeneration process was effective. The leaching test indicated that the catalysts are heterogeneous in the evaluated operating range. The catalysts investigated showed themselves promising for the production of biodiesel.

Caracterização mineralógica, química e solubilização do potássio de glauconita modificada

Demand for potassium in Brazil is large and is constantly increasing, but only about 5% of all consumed potassium is produced in the country. This low domestic production implies high rate of potassium imports, leaving the country vulnerable in the event of any difficulty to import this product and currency fluctuations. The modified glauconite is a rock that has a high potential for potassium exploration, found in Minas Gerais state, its extraction is relatively cheap and the prospected rock volume is high. The difficulty for its use as a direct source of potassium is in its low solubility. Thus, the objective of this study was to perform a chemical and mineralogical characterization of the modified glauconite and evaluate the effectiveness of techniques and treatments in the potassium solubilization contained in the rock. For this study, it was used characterization techniques such as X-ray diffraction, scanning electron microscopy, diffraction by Synchrotron Light and chemical analysis of high and low power of potassium extraction. Also granulometric testing and thermal treatments with different forms of calcination were carried out. Overall, it was found that the modified glauconite is a compound of minerals, of the mica groups K-feldspar and quartz and calcination substantially alter the crystal structure of these minerals, increasing the potassium availability. While the natural solubility of glauconite modified be very low, rock calcination added with high fluxes of calcium and low magnesium content at 1200 °C led to potassium solubility increase in order of 100 times compared to that observed in the glauconite natural modified.

Recuperação e aplicação do dicromato de potássio proveniente do resíduo de sulfocrômica

A simple procedure for recovering potassium dichromate (K2Cr2O7 ) from treatment of residual sulphochromic solution was proposed in the present work by means of cooling crystallization. The decrease of temperature favored the crystallization of K2Cr2O7 due to the decrease of solubility. 5.0 L of sulphochromic wastes containing 48.08 g L-1 of Cr(VI) were treated and the process of crystallization was performed in three steps until crystals were not formed anymore. On each step the content of Crtotal was determined by flame atomic absorption spectrometry and Cr(VI) by colorimetric method with 1,5- diphenylcarbazide, resulting in the removal of 91% and 92% of Crtotal and Cr(VI), respectively. After the last step, the remaining Cr(VI) in the solution was reduced to Cr(III) from the addition of NaHSO3 , recovering via precipitation in pH 8 approximately 36.13 g of Cr(OH)3 . The final supernatant was discarded since chromium content was below the maximum limit established by the Brazilian legislation for effluents discharge, which corresponds to 0.10 and 1.0 mg L-1 of Cr(VI) and Cr(III), respectively. 628.4 g of K2Cr2O7 were recovered and the salt was characterized by X-ray diffraction and differential thermal analysis. Its applicability was compared to the standard K2Cr2O7 when determining the soil organic matter, in which there was no significant difference, thus inferring that the recovered compound may be incorporated on routine analyses. This recovering process allowed the reuse of K2Cr2O7 , thus reducing costs with the acquisition of new reagents and environmental impacts caused by the inadequate discard of sulphochromic solutions.