The mesoporous material Al-Mobil Composition of Matter No. 41 (Al-MCM-41) was successfully obtained from kaolin, a low cost raw material, by means of hydrothermal route. The process of synthesis of Al-MCM-41 was based on calcination of kaolin, dealumination by acid treatment, hydrothermal synthesis in alkaline medium and surfactant extraction. The characterization of the obtained mesoporous material was carried out by techniques such as: X-ray diffraction, infrared vibrational spectroscopy, 29 Si and 27 Al solid state nuclear magnetic resonance, scanning electron microscopy, transmission electron microscopy and N 2 adsorption-desorption. The X-ray diffraction at low angles allowed the determination of the cell parameter, which was 4.02 nm. The analyses of scanning and transmission electron microscopy revealed important morphological properties of the synthesized material. N 2 adsorption/desorption showed a Brunauer-Emmett-Teller (BET) specific surface area of 1,303 m 2 g-1 , pore volume of 1.23 cm 3 g-1 and average diameter of 2.45 nm. The mesoporous material presented a maximum adsorption capacity of 316 mg g-1 for the cationic dye methylene blue (MB) in a concentration typical of industrial effluents, which makes it a potential adsorbent for MB removal from wastewaters.

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Coprecipitation is one of the most practical methods used to synthesize ferrite nanoparticles. Fine characteristics of these materials can be improved by means of a series of modifications in the synthesis method. In this paper we present a study of influence of glycerol as structure directing and stabilizing agent in the synthesis of zinc ferrite nanoparticle, exploring its chelating capacity and oxidation. The studied materials include two series of zinc ferrite samples and its precursors obtained with or without glycerol throughout different stages during the synthesis process. The structural and morphological characteristics were evaluated by means of different techniques such as X-ray diffraction, Fourier transformed infrared spectroscopy, scanning and transmission electron microscopy and thermal analysis. The oxidation of glycerol was determined by high-performance liquid chromatograph. The obtained results demonstrate that zinc ferrite crystals synthesized in the presence of glycerol are initially bigger than those synthesized in absence of it, but according to the oxidation process they tend to decrease giving rise to intermediate phases. Interestingly, these samples grow back during more advanced stages and become structurally better organized, compared to the series of samples produced in absence of glycerol. These results indicate that glycerol is capable to modify the synthesis route of zinc ferrite nanoparticles via coprecipitation, acting directly over the size and morphology of the crystals.

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Nanomaterials can play an important role in antibacterial applications. Various nanostructured metallic particles have been used for nanocomposite packaging materials. Silver nanoparticles (AgNPs) are regarded as an antibacterial agent for food package. The objective of this study was to prepare antimicrobial nanocomposite films using gelatin and AgNPS. Gelatin was used as a polymer matrix for reduction and stabilization of the silver nanoparticles. Films were characterized by XRD, XRF, UV-Vis, FTIR, and antibacterial activity. Gelatin (3.0 g) was stirred at ~90 °C for 30 min. The pH of the solutions was adjusted to pH 11, then 1 mL of AgNO 3 at various concentrations (0, 45, 90, and 180 mmol.L-1) was added drop-wise into the solution mixtures. The neat gelatin (gel) and gel/AgNPs 45 mmol.L-1 films did not show any UV-Vis absorption peak in ~430 nm, but gel/AgNP 90 mmol.L-1 and gel/180 mmol.L-1 films exhibited a high absorption peak, which is related to the collective oscillations of the surface electrons. All FTIR peaks of the gel control and of the gel/AgNP show similar spectrum. The higher AgNPs concentration in the films, the higher the antibacterial activity against food-borne pathogens. The X-ray diffractograms of films was carried out for identifying crystalline phases by PANalytical X'pert High-Score Plus software, in which, showed the presence the peaks position (2) at 32.2°, 54.7°, 55.5° and 74.6° to gel/AgNPs 90 mmol.L-1 and 11.7°, 28.5°, 50.5° to 180 mmol.L-1 for silver. But wasn´t possible identify to gel/AgNPs 45 mmol.L-1 , because the low concentration. Was possible to produce crystalline silver nanoparticles in the gelatin films and obtain films with antimicrobial activity.