The treatment of wastewater has proven to be a critical challenge in recent years. In light of this, the refinement in the development of carbonaceous catalysts obtained from biomass has emerged as a clean and effective solution, particularly for enhancing the efficiency of advanced oxidative processes (AOPs), such as the sono-Fenton process. Therefore, this study aimed to develop and characterize carbonaceous catalysts modified with iron chloride at different pyrolysis temperatures (300°C, 525°C, and 750°C), named CGFe-P300, CGFe-P525, and CGFe-P750, respectively. These materials were produced through the pyrolysis of pre-treated coffee grounds with an FeCl3·6H2O solution to obtain an efficient material for the degradation of organic dyes. The physical and chemical characteristics of the microstructures of these materials were investigated using XRD, FTIR, SEM-EDS, and TGA. X-ray diffraction patterns for the catalysts treated at higher temperatures showed high correspondence with patterns reported for Fe2O3. FTIR analyses revealed that even in different thermal environments, the bands corresponding to the functional groups of the precursor remained largely unchanged. The morphology and presence of iron were confirmed by SEM/EDS in all catalysts, with a notable 18.5% loading in CGFe-P300, essential in catalyzing the Fenton reaction. Thermogravimetric analysis showed greater thermal stability in catalysts treated at higher temperatures, suggesting better resistance to thermal degradation. The effectiveness of these materials in wastewater treatment was evaluated through controlled catalytic efficiency tests, with CGFe-P300 exhibiting the highest reduction in the concentration of model pollutants after 45 minutes of ultrasonic irradiation (methylene blue ≅ 95%; methyl orange ≅ 97%), with minimal efficiency loss under varying operational parameters.

The significant growth of shrimp farming in tropical and developing countries has brought about challenges in waste and byproduct management. Shrimp waste is a valuable source of carbon and other biomolecules, with astaxanthin standing out due to its antioxidant and antimicrobial properties. Antioxidants play a crucial role in inhibiting oxidative chemical reactions and hold significant value for the food industry as essential substances to ensure food quality. On the other hand, antimicrobial properties work to inhibit or delay the growth of microorganisms, extending the shelf life of food products. When these additives are incorporated into packaging formulations and interact with the food, they function as active agents, providing the packaging with antioxidant and antimicrobial properties. For this reason, the objective of this work was to manufacture bacterial cellulose (BC) films using shrimp waste flour from the Litopenaeus vannamei species in situ as a substrate to develop biodegradable active packaging. To produce BC, the bacterium Gluconacetobacter hansenii was cultured in a pure saline medium with the addition of waste at concentrations of 5 g/L, 10 g/L, and 20 g/L, as well as through glucose at the same concentrations, compared to the standard HS medium. The study involved analyzing Water Retention Capacity (WRC), porosity, Fourier Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscopy (SEM), antimicrobial activity, and antioxidant activity. The saline medium demonstrated better yield. The waste particle load exhibited a uniform distribution on the film, and the material showed low porosity. Additionally, higher thermal stability of the saline medium was observed. Antimicrobial and antioxidant activities were confirmed, along with characteristic carotenoid bands in FTIR. Based on the results obtained, it is concluded that the addition of shrimp waste is a natural antioxidant and has the potential for the development of active packaging.

Chitosan is a biopolymer derived from the deacetylation of chitin, which is the most abundant component in the shells (exoskeletons) of shrimps, crabs, and other crustaceans. It can also be obtained from insects, fungi, bacteria, and yeast. Chitosan is the second most abundant natural polysaccharide on Earth, after cellulose. This study addresses the use of chitosan in partially replacing Portland cement in injection mortar. All tests were conducted in accordance with current technical standards. Thus, this work analyzes the influence of chitosan on the compressive strength and microstructure of the injection mortar. To do so, a chitosan replacement percentage of 0.1% was established based on literature and preliminary results from our group. The mixture for the prepared samples was determined, and then the mortars were produced. The specimens were assembled next. With the mortars still unset, flow and working life tests were performed. Subsequently, with the hardened specimens, axial compressive strength tests and microstructural analyses (XRF; SEM/EDS; XRD; and FTIR) were carried out. The obtained results demonstrated that chitosan, at the relative concentration used, is capable of partially replacing cement in injection mortars without compromising the compressive strength and complying with current technical standards. Thus, the partial replacement of cement with chitosan in injection mortars, even in low proportions, emerges as a promising alternative in the development of sustainable construction materials.

Among nanometric materials, mesoporous silica (SiO2) has been gaining prominence due to the possibilities of applications in different areas according to the size of the nanoparticle. The synthesis of hybrid materials, obtained by supporting trivalent europium ion (Eu3+) complexes on silica nanospheres of the MCM48 type using ligands derived from trimesic acid (BTC) and chelidamic acid (DAMIC), motivated this work, due to the potential for use of these materials to make paints and act in security devices. Thus, a molecular model was proposed to understand the intramolecular energy transfer mechanism that leads to the luminescence of hybrid materials of this type. The modeled structures were obtained with the calculation level PBE1PBE/MWB52/6-31G(d) and AM1/Sparkle. The energy levels of the singlet and triplet excited states, obtained from TD-DFT calculations at the LC-wPBE/MWB52/6- 31G(d) level, showed that the complexes studied tend to present luminescence, in agreement with the experimental data. The calculation of Judd-Ofelt intensity parameters was performed using the chemical bond overlap polarizability model implemented on the JOYSpectra web platform. The calculation of intramolecular energy transfer rates was carried out using the method proposed by Malta and collaborators (2019); and the calculation of luminescence lifetime and luminescence quantum yield, based on solving the rate equations numerically using the fourth order Runge-Kutta method with adaptive time step. The structural model proposed for complexes with btfa ligands provides data compatible with experimental data. The results provide more favorable energy transfer mechanisms via the triplet state of the ligand to the 5DJ level (J = 0, DAMIC and J = 1, BTC) of the ion, followed by transfer via the singlet state to the 5G2 level. Future measurements of quantum yield (Q%) may help to understand the differences in the luminescence process related to the intrinsic characteristics of the ligands, evaluated by proposing three scenarios (Q% = 1, 20 and 50). The proposed model and procedures used in this work were appropriate and could assist in the investigation of new systems that enable the development of more efficient devices.

Pollution caused by incorrect disposal of polymers is responsible for major environmental impacts, as the degradation of these polymers from non-renewable sources is quite slow. An alternative to minimize this impact on the environment is the use of biodegradable polymers, such as Poly(butylene-adipate-co-terephthalate) (PBAT) with the insertion of oils and vegetable residues, thus presenting good mechanical properties as well as high biodegradability in the environment and good processability especially for films, properties that produce a biocomposite suitable for packaging production. Thus, in this study, biodegradable matrix biocomposites (PBAT) were developed with castor oil (OM), residues with/without chemical treatment of malt bagasse (BM) or corn stover (PM). The waste that underwent chemical treatment was subjected to alkaline treatment of 2, 4 and 6% in an autoclave, at 121°C and 1 atm, for 10, 20 and 30 min. Subsequently, the biocomposites were processed, containing a load of 5, 10 and 15% of waste, in natura and treated with 5% OM, in a mini-extruder and characterized by Infrared Spectroscopy (FTIR), X-ray Diffraction ( XRD), Scanning Electron Microscopy (SEM) and Thermogravimetry (TG). The alkaline treatment of the residue proved to be more efficient in removing the hemicellulose and lignin present. Another relevant result concerns the thermal stability of the PBAT matrix during processing, which may be attributed to the insertion of fibers. The residues in PBAT biocomposites improved the biodegradation process, accelerating the degradation process in simulated soil, reaching complete biodegradation in 6 months of PBAT+BM+OM, consistent with morphological images indicating cavities, ersion and roughness on the surface of the films where these physical changes indicate biodegradation. This shows the efficiency of our developed biodegradation system.

The properties of object arrays have gained a lot of attention from the scientific community due to applications and still unsolved academic problems. An array can be studied magnetically using microscopy techniques. Numerical approximations can also be applied to obtain theoretical predictions with the solution of the micromagnetism equations. Especially when it comes to extensive arrays, whose objects present interactions, doubts arise as to the effects of the dipole energy of interaction between objects and the boundary conditions to be applied when solving the problem. When dealing with micrometric objects, different magnetization configurations can arise within the elements that form the array. In this work we present the fabrication of arrays of disks and ellipsoids arranged in square order. The responses obtained in magnetization measurements with different directions of the external field allow studying how each arrangement behaves. The measurements were carried out by applying an external magnetic field in the plane of the two-dimensional array and changing its orientation in relation to the main directions. The objects obtained here were manufactured with optical writing using the DWL66 system and Permalloy sputtering deposition. The deposition of magnetically soft material facilitates the fact of disregarding effects of magnetocrystalline anisotropy. Magnetic measurements were performed using vibrating sample magnetometry (MAV) which reveal soft ferromagnetic behavior at room temperature according to the simulations. The morphological characterization of the samples was performed by optical microscopy and scanning electron microscopy (SEM). For the micromagnetic simulations we use the Object Oriented Micromagnetism Framework (OOMMF) code to study the magnetization process of objects. The code is based on the Landau-Lifshitz-Gilbert equation to simulate the configuration of the magnetic moments and calculate the magnetization energy of the microstructures. The results are compared with data obtained experimentally. Coercive fields have an error of only 2%, possibly due to temperature conditions. The magnetization diagrams show the presence of multiple magnetization mechanisms in this system.

Materials have been developed and used with specific characteristics that meet the needs of a modern and complex society. Among the types of materials, we have nanomaterials that are within the advanced materials. Among these materials, a group that stands out for its wide range of applications is metallic nanoparticles, such as silver nanoparticles (AgNPs). AgNPs have excellent characteristics, which are responsible for optical, electronic, and antibacterial properties. AgNPs are also efficient nanocatalysts, showing efficiency in several reactions, such as the catalytic reduction of organic pollutants. Thus, this work had as its main objective the synthesis of metallic nanocatalysts based on silver nanoparticles in water, and to evaluate their catalytic activity in the degradation of 4-nitrophenol (4-NF). The AgNPs were prepared in spherical format, through the chemical reduction method using sodium borohydride. As stabilizers, we used polymers: poly 4-styrene sulfonate, polyvinyl alcohol, sodium polyphosphate, and sodium alginate; and minor ligands: ascorbic acid, succinic anhydride, glycine, tyrosine, and sodium citrate. AgNPs were characterized by UV-Vis spectroscopy, dynamic light scattering, Zeta potential, and ICP-OES. The obtained results indicate the formation of silver nanoparticles with spherical morphology, colloidal stability, and good size distribution. The catalytic reduction of 4-NF to 4-aminophenol in the presence of silver nanocatalysts was studied by UV-Vis spectroscopy, in the presence of sodium borohydride. The catalytic studies were performed using different volumes of AgNPs (0.5, 0.25, and 0.1 µL), and the analysis was performed at 0, 5, 15, and 30 min. Complete degradation of 4-NF was observed in less than 30 minutes with all catalysts, and this catalytic efficiency is dependent on the amount of AgNP used. Thus, the AgNPs studied here have the potential to be used as nanocatalysts in the degradation of organic pollutants.

Lead-acid batteries have been used since more than a century in many applications. The longevity of the technology is explained by several factors, including reliability, safety, recyclability and relatively low cost. However, one of the biggest problems is the low energy density, related, partly to the high density of the components (Pb) and partly to the low effective use of the active material. Another problem is related to cycle life, partially related to the degradation of the positive electrode, which occurs both, by corrosion of the current collector and by disaggregation, or shedding of the positive active material. In this sense, improving the use of active material and searching for strategies to hinder the shedding of positive active material turns into increase in efficiency, considering the two aspects mentioned above. The use of additives in the production of positive paste, such as 3BS and 4BS seeds,can improve the durability and increase the effective use of the active material. These are the aspects studied in the present work: the synthesis of 3BS and 4BS and subsequent application as additives in paste preparation, and then the use as the positive electrode of prototypes of lead-acid cells. The synthesisof the additives was achieved by mixing industrially lead oxide with adequate amounts of H2SO4, in aqueous medium, at temperatures up to 100oC. The positive plates containing the additives were used in the manufacture of 2 V prototypes and the results showed an increase in the use of the active material, around 3%, which can be explained, at least in part, by the change in the porosity of the plate. Apparently modest, this improvement may result in a decrease in the use of raw material to produce positive plates, which can reach more than a million reais per year. The reduction of costs is an attribute always welcomed by the industry and justifies the efforts involved in the investigation. 

Several studies with lanthanide oxides have been attempting to develop materials for efficient energy upconversion, due to its innumerous possibilities of applications in the field of photovoltaic energy. These efficient materials will be able to take advantage of a large part of the solar spectrum (infrared) that is lost in conventional photovoltaic panels and convert it into visible light, increasing the efficiency of these panels. Thus, the present work aimed at investigating the influence of a thermal insulating matrix coated with PrO2 and Yb2O3 oxides exposed to a near-infrared (NIR) laser in upconversion processes. The oxides and nanocomposites with silica, SiO2/PrO2 and SiO2/Yb2O3, were synthesized via Pechini method. These materials exhibit intense absorption from the visible to NIR, resulting in high temperatures upon excitation at 980 nm with power densities ranging from 0,5 to 4,5 W cm−2 and emitting very bright white light by thermal irradiation. The steady-state temperatures were estimated by the blackbody (Planck) distribution, which were higher than 2000 K for the SiO2/Yb2O3 hybrids under low pressures. It was also observed that for the SiO2/PrO2 hybrids, the concentration of oxides did not affect the emission intensities, in contrast to the SiO2/Yb2O3 hybrids for which the concentration increase directly affects the rise of the emission intensity for the same excitation power density. In general, the increase in excitation power results in an increase in local temperature and, consequently, the brightness of the broadband emission intensity, ascribed to blackbody emission. For the SiO2/Yb2O3 hybrids, it was observed the formation of micro spheres under irradiation at 980 nm, which could lead to a new synthetic approach to ytterbium oxides. Additional efforts are needed to develop these new materials into efficient thermophotovoltaic applications. However, it was shown that the incorporation of thermal insulating materials with high chemical stability still make viable the process of photoinduced thermal bright emissions.

This work reports the synthesis, characterization, luminescent properties and photo-oxidation chemical reaction of the β-diketonate complex [Eu(mppd)3] (mppd = anion 1,3-Bis-(1-methyl-1H-pyrrol-2-yl) propan-1,3- dionate). In addition, we have investigated the preliminar UV dosimeter and molecular thermometer applications of its photo-oxidized form, [Eu(mppdOH)3]. Initially, the protonated ligand Hmppd (1,3-Bis-(1-methyl-1H-pyrrol-2-yl) propan-1,3-dione) was synthesized from the reaction between N-methylpyrrole and malonyl chloride. The Hmppd was characterized by 1H NMR, thermogravimetric analysis and gas chromatography-mass spectrometry. The complex [Eu(mppd)3] shows photoluminescence in the red region (5D0  7FJ, J = 0, 1, 2, 3 and 4) and undergoes photo-oxidation when exposed to UV radiation at 344 nm, resulting in the intensification of the luminescence of the Eu3+ ion. After 15 minutes of irradiation, the emission intensification reaches a plateau that is maintained for 10 minutes until it starts to fall. Attempts were made to produce luminescent devices by inserting the mppd ligand or the [Eu(mppd)3] complex in a supramolecular matrix of hydrogel and in a polymeric matrix of polyvinylpyrrolidone. However, these procedures have not produced satisfactory results. Furthermore, the photostability of the photo-oxidized complex, [Eu(mppdOH)3], under UV radiation exposure (λirr = 343 nm) was evaluated. The emission intensity had a loss of 80% after 60 minutes of exposure, evidencing its photodegradability. Moreover, the thermometric behavior of the [Eu(mppdOH)3] complex was investigated in the physiological temperature range, 303 to 323 K, using the ratio between the integrated emission intensities of the Eu3+ ion and the ligand (IEu/EiLig) as the thermometric parameter. The activation energy found by the Mott-Seitz model was 4,239 cm-1, assuming, therefore, that the Eu3+ charge transfer band is the main mechanism of luminescence deactivation. 

In this work, the influence of partial replacement of fine aggregate by glass waste was investigated in the mechanical property of compressive strength in mortars, as well as on the manufacturing stages. Mortars with glass waste substituting sand in the proportions of 10%, 20% and 30% in relation to the proportion adopted between cement and sand were manufactured, as well as mortars without this substitution. For the four cases 6 kg of cement, 2.9 kg of lime, 21 kg of sand and 4 kg of waste glass were used, using a water/cement ratio of 1.3. The compressive strength results revealed that the strength of mortars with glass waste decreased compared to the strength of the reference mortar, at both ages. Despite this decrease, the difference in mechanical behavior was small (< 1 MPa). Although it has caused a slight decrease in mortar strength values, the incorporation of glass waste in the mixtures has promoted a better workability of the mixtures, since the material does not absorb water. Additionally, chemical, structural, and microstructural characterization of the precursor materials and the obtained products was performed. Thus, X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS) and thermogravimetry (TG) analyses were performed. From the XRD analyses it was possible to identify the use of calcitic mortar, as well as the presence of systems such as quartz and hydrated calcium silicates. Through the SEM/EDS results it was possible to notice the good formation of the cement hydration products ettringite and portlandite, and with the thermogravimetric analysis the effect of high temperatures on the mortars. The results also showed that the mortars without glass waste showed the highest compressive strength values when compared to the cases where the sand was replaced by waste. Finally, when evaluating all the different types of mortars produced in this dissertation, the additions of 10% and 20% of glass waste lead to mortars with greater potential for applications in civil construction. 

Smart polymeric materials capable of responding to external stimuli have great potential for application in the industrial or biomedical area as sensors, electronic devices, packaging, dressings, systems for controlled drug release, support for cell growth, among others. Poly(N- vinylcaprolactam), PNVCL, is a thermoresponsive polymer, whose change from hydrophilic to hydrophobic behavior occurs by changing the temperature, and shows promise due to its non-toxicity, biocompatibility and for having a phase transition temperature of hydrophilic to hydrophobic close to physiological temperature. However, the production of finished products with PNVCL is difficult due to its high mechanical fragility. The improvement of PNVCL properties can be achieved through physical mixing with other polymers, making a polymer blend. In addition, mixing with other polymers also allows changing the phase transition temperatures of PNVCL, which can broaden its application spectrum. In the present work, thermoresponsive plastic films produced by molding in solution from polymeric blends containing different mass proportions of PNVCL and thermoplastic polyurethane (TPU) in the proportions 90/10 70/30 and 50/50, respectively, were made. The films were resistant, flexible and with varied thermal responsiveness depending on the formulated composition. Scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy by attenuated total reflection (FTIRATR), thermogravimetry (TGA) and differential scanning calorimetry (DSC) analysis confirmed the miscibility of the blends formed and the angle analysis contact test showed that the films present thermal response. It was possible to induce a change in solid films from transparent to opaque by varying the temperature and verify the reversibility of this change. In addition, mechanical tests of traction/deformation were carried out, which proved the mechanical improvement of the PNVCL blends when incorporating TPU. The material developed in this work is innovative and has potential for application in many areas.

As technologies evolve, functions other than conventional ones are required of plastic materials. In this sense, there is a growing demand for new polymers with specific functions, and one way to add these functionalities to polymers is through the use of natural additives, such as ginger, for example. Ginger rhizomes (Zingiber officinale) contain substances with several properties of interest, including enzymes with proteolytic activity, called Zingibaine. The interaction of enzymes with polymers can enable biological functions to be transferred to polymeric materials and bring improved functionality to these materials. In the present study, the extrusion technique was used to add ginger powder to the biodegradable polymer Polycaprolactone (PCL), with the objective of developing a functional polymer with proteolytic property, using the protease of ginger powder (Zingibaína) as a proteolytic agent and PCL as a polymeric matrix. The developed materials were characterized by Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), mechanical assay and scanning electron microscopy (SEM). Furthermore, the presence of proteolytic activity in the formed polymers was evaluated. The results indicated the feasibility of using extrusion processing to incorporate the protease present in ginger powder into the polymer, where the three studied compositions showed proteolytic activity. FTIR analysis indicated that the matrix material was preserved after the addition of ginger powder. The TGA thermal analyzes showed that the PCL formulation with 3% ginger powder showed similar behavior to pure PCL. However, the formulations with 5% and 7% ginger showed a decrease of approximately 7.0°C and 7.5°C, respectively, in the initial degradation temperature. The DSC results showed that the concentrations used did not produce relevant thermal changes in these properties. The tensile tests showed that the elastic modulus did not vary significantly in any of the studied compositions. The values of stress at rupture and deformation at rupture decreased for samples with 5% and 7% of ginger powder, corroborating the SEM images. Therefore, with this study it was possible to develop a functional polymer, bringing the biological functions of the enzymes present in the ginger powder to the PCL matrix, without major changes in the matrix properties, thus expanding the applications of this biodegradable polyester.

As the economies develop and prosper, we will face challenge to feed the demand of more than two-fold energy increase in this century. The increasing demand created fierce worldwide competition for the gradually depleting fossil fuel reserves. Meanwhile, increasing greenhouse emission results in global climate change. All these situations require our society to move towards sustainable and renewable energy resources, such as solar and wind energy. However, due to intermittent feature of solar and wind source, energy storage systems play a key role to the proper utilization of solar and wind energy. Effective chemical storage (e.g. lithium-ion battery and supercapacitors) thereby becomes imperative in the future energy technologies to provide electrical transportation power for commuters and to store energy from intermittent solar or wind power. The electrode is a critical component for controlling the performance of such devices. The fabrication of a high-performance electrode material involves some critical properties such as high conductivity, large specific surface area, temperature stability, good distribution of pores with optimized size, good corrosion resistance, and cost effectiveness. In this sense, porous materials, including Metalorganic Frameworks (MOFs), have been very promising in their application in energy storage devices; however, the problem of low electrical conductivity of such materials needs to be overcome. The association of MOFs with carbonaceous materials has been proposed as an efficient alternative to improve the electrochemical performance of such materials. Therefore, this work aims to synthesize metalorganic frameworks as well as their composites with carbon nanotubes (CNTs) and apply them in supercapacitor electrodes. The Metalorganic Frameworks were synthesized via sonochemical method, from zinc and copper salts coordinated to benzenedicarboxylate ligands. The formation of the composites was carried out by the method of Pickering emulsion, which consists of the formation of an emulsion stabilized by solid particles. The Metalorganic Framework of zinc (ZnMOF) or copper (CuMOF) was dispersed in dichloromethane, oil phase, and the functionalized carbon nanotubes dispersed in distilled water, water phase. The samples were characterized by the X-ray diffraction method, absorption spectroscopy in the infrared region with Fourier transform, scanning electron microscopy and thermal analysis. The electrochemical behavior of Metalorganic Frameworks and their composites was evaluated by the cyclic voltammetry technique using coin cell devices.

A produção de hidrogênio tem sido um campo de intensa investigação devido ao seu potencial como vetor energético limpo e versátil. Este trabalho se concentra na utilização de nanocatalisadores de cobre, baseados em estruturas metal-orgânicas (MOFs), para a produção de hidrogênio via desidrogenação do borohidreto de sódio. O objetivo principal é avaliar o potencial desses nanocatalisadores e compreender seu desempenho na reação de desidrogenação. O estudo inicia-se com a análise da eficiência dos nanocatalisadores de cobre/MOFs como promotores da reação de desidrogenação do borohidreto de sódio. Avaliações detalhadas incluem a determinação dos rendimentos, taxas de formação e a frequência de rotação (TOF) em diferentes temperaturas (25 °C, 35 °C e 45 °C). Além disso, é investigada a viabilidade de reutilização dos nanocatalisadores/MOFs, visando avaliar a sua atividade catalítica em ciclos consecutivos. Outro ponto de interesse é a avaliação da estabilidade dos nanocatalisadores/MOFs em um meio alcalino. Este estudo oferece uma contribuição significativa para a pesquisa em produção de hidrogênio, ao explorar os nanocatalisadores de cobre/MOFs na desidrogenação do borohidreto de sódio. As caracterizações em FTIR dos catalisadores/MOFs foram realizadas antes e depois da reação de hidrólise, para observar ou identificar mudanças na estrutura molecular e em ligações químicas. Todas as análises foram conduzidas em triplicata para reduzir erros sistemáticos e determinar o desvio padrão dos resultados obtidos. A estabilidade catalítica foi um ponto de destaque na análise dos ciclos de reutilização do catalisador/MOF. Notou-se que, embora o Cu-BDC tenha mantido uma produção estável do segundo ao quinto ciclo, o ponto negativo dessa estabilidade tornou-se evidente no primeiro ciclo. Além disso, a introdução de NaOH no sistema apresentou um efeito inesperado, resultando em uma drástica queda na produção de hidrogênio.

Graphite is used in mechanized agriculture as a natural lubricant. Graphite powder is added to the seeds with the sole aim of reducing friction with the mechanics of mechanical seeders. In this study, a system was developed to perform the direct exfoliation of graphite powder Grafsolo® (Nacional de Grafite Ltda.) under high nitrogen pressure to obtain few-layer graphene (FLG) with the incorporation of nitrogen at the edges to add value with the functionalization of the lubricating material. Among N, P, and K, Nitrogen was chosen as a macroelement model, and an entire indoor cultivation system was designed and automated to choose a cultivar model as a plant ideotype for the tests. Based on the established parameters, santa cruz okra was chosen as a cultivar model, and the first trials were planned and carried out at this master's project. This approach established a proof of concept (PoC) for introducing high-pressure nitrogen while adhering to a solvent-free and environmentally friendly process. As a raw material, the choice of Grafsolo® was strategic, as this type of powdered graphite is widely used in various crops by the agroindustry and is commercially available, which favors the feasibility of scaling production. Focusing on agricultural applications, the research explored nitrogenous graphene as a coating for okra seeds of the santa cruz 47 type (ISLA Sementes Ltda.) during planting, aiming to provide more nitrogen as a primary macronutrient. For this, optimizations were carried out in the milling system to obtain nitrogenous graphene and the indoor cultivation system, guaranteeing an environment in conditions similar to the natural one for seed germination. The detailed characterization of the material was conducted using infrared spectroscopy (FTIR), scanning electron microscopy (SEM), X-Ray Diffraction (XRD), thermogravimetric analysis (TGA), and differential thermal analysis (DTA). Based on the results obtained, the efficiency of graphite exfoliation and the presence of nitrogen were verified through FTIR analysis. SEM images demonstrated the viability of producing nitrogenous graphene using the high-pressure mechanochemical method.

The europium ternary complexes, coordinated with β-diketonate ligands, exhibit luminescent properties under ultraviolet radiation and find applications as luminescent thermometers, biological markers, and inorganic diodes. Highlighting the efficient synthetic routes, the Faster Synthesis method, developed at Lom, demonstrates high yields and reduced complex acquisition times. Advancing this methodology, the use of a microwave reactor results in a more sustainable approach with even shorter synthesis times and enhanced product purity. Our findings emphasize the crucial role of ligand addition order and the introduction of "symmetry-breaking" ligands in intensifying luminescence quantum efficiency. Current focus involves exploring luminescence properties with other symmetry-breaking ligands, adapting the Rapid Synthesis methodology to microwave reactors using different europium salts. In this dissertation, luminescent europium ternary complexes were synthesized in a microwave reactor with one or two symmetry-breaking ligands, with general formulas [EuX(β)₂(L)₂] and [EuX₂(β)(L)₃], where X = Cl^- or NO₃^-, β = BTFA (4,4,4-trifluoro-1-phenylbutan-1,3-dionate) or TTA (4,4,4-trifluoro-1-thiophen-2-yl-butan-1,3-dionate), and L = TPPO (triphenylphosphine oxide) or PTSO (p-tolylsulfoxide). Our evaluation of Cl^- and NO₃^- ligands' influence on complex structure, synthesis yields, and luminescence efficiency revealed generally higher yields with Cl^- ligands, exemplified by [EuCl₂(BTFA)(TPPO)₃] and [Eu(NO₃)₂(BTFA)(TPPO)₃] showing synthesis yields of 91% and 40%, respectively. Computational calculations of thermodynamic properties supported experimental results, indicating energetically favorable syntheses with Cl^- ligands compared to NO₃^-. Luminescence property results highlighted the significant impact of the nitrate ligand on increased quantum efficiency, followed by the BTFA ligand in complexes such as [Eu(NO₃)(BTFA)₂(TPPO)₂] (η = 57%), [Eu(NO₃)₂(BTFA)(TPPO)₃] (η = 52%), [EuCl(BTFA)₂(TPPO)₂] (η = 51%), and [EuCl₂(BTFA)(TPPO)₃] (η = 49%). Conversely, the absence of nitrate or chloride led to lower quantum efficiency, as observed in the complex with three β-diketonates: [Eu(BTFA)₃(TPPO)₂] (η = 34%). These results indicate that inorganic ligands appear to disrupt the spherical symmetry of the complex, enhancing luminescence. Our study contributes to the development of simpler and more economical synthetic routes using microwave procedures and design strategies to enhance luminescence in europium complexes coordinated with β-diketonate ligands incorporating inorganic ligands.

Nanotechnology, as an emerging field, is widely used in the areas of clean energy generation and public health, which are current and relevant global problems to be solved. In this sense, metallic nanoparticles (MNPs) have been extensively studied for their magnetic, electronic, optical, antimicrobial and catalytic properties. The manipulation of MNPs to create new materials with specific desired physicochemical properties has shown promise. The combination of MNPs with a porous nanomaterial, such as Metal-Organic Framework (MOF), suppresses the main problem of MNP applications, which is the aggregation resulting from high surface energies. This work presents the synthesis and characterization of nanocomposites based on zinc MOFs, [Zn₂(1,3-bdc)(Bzim)₂] and [Zn(mim)], as support for the incorporation of MNPs (M= Cu, Ag or Au) in order to avoid aggregation and improve properties with respect to their counterparts. For this proof of concept, the Ship in bottle and One-pot methods were used. The synthesized materials were characterized by XRD, SEM, FTIR, ICP-OES, TGA/DTA and BET. MNPs were characterized by absorption spectroscopy in the UVvisible region. The catalytic properties of the synthesized materials were evaluated using the water displacement method, measuring the volume of hydrogen gas generated in the dehydrogenation of the hydrogen storage molecule NH₃BH₃ with the dependence of time, varying temperature and NaOH. Antibacterial properties were evaluated from disc diffusion tests on bacteria against Gram-positive and Gramnegative bacterial strains. The incorporation of MNPs by the methods used did not alter the stability and structural crystalline characteristics of the nanomaterials. The nanocomposites OP:AuNPs@Zn(mim) and OP:AgNPs@Zn(mim) stood out as catalysts for presenting excellent catalytic activities in the hydrolysis of NH₃BH₃, with high rates of hydrogen generation (1979.53 mL min-1 gAu- 1 and 3352.71 mL min-1 gAg- 1) and high efficiency (69.16% and 98.5%). The activation energies were 19.6 kJ.mol- 1 for OP:AuNPs@Zn(mim) and 38.13 kJ.mol-1 for OP:AgNPs@Zn(mim), which are lower than for most of the catalysts containing Au/Ag-MOF used in the hydrolysis of NH₃BH₃ described in the literature. Furthermore, these catalysts showed good stability and reuse, preserving 71.42%, OP:AuNPs@Zn(mim), and 88.23%, OP:AgNPs@Zn(mim), of their initial catalytic activities after five cycles. As biocidal agents, the Zn₂(1,3-bdc) (Bzim)₂ support effectively prevented the aggregation of MNPs and the bactericidal properties of the nanocomposites were enhanced up to thirteen times greater than the nanoparticle without the metalorganic support and up to sixteen times greater than the antibiotic amoxicillin. Therefore, the materials presented here proved to be excellent candidates to produce hydrogen from NH₃BH₃, in particular, OP:AgNPs@Zn(mim), with the combination of a simple synthesis method, low reaction temperature, environmentally friendly solvent, low content of of MNPs, relatively low cost and mild dehydrogenation conditions. From another perspective, the nanocomposites of the Zn₂(1,3-bdc) (Bzim)₂ support with AgNPs and CuNPs showed promise as biocidal agents, being more economical and with a low content of MNPs.

BLENDAS POLIMÉRICAS: INTERAÇÕES E PROPRIEDADES

Neste trabalho foram desenvolvidos dois novos géis poliméricos aplicados à RMN em meios orientados para o estudo da elucidação estrutural de moléculas orgânicas pequenas a partir de parâmetros anisotrópicos, como o acoplamento dipolar residual (RDC) e anisotropia do deslocamento químico residual (RCSA). A eficiência do gel de N,N-dimetilacrilamida/acrilonitrila (DMA/AN), compatível com acetonitrila-d3 e metanol-d4 como meio de alinhamento, foi testada usando as moléculas α-santonina e brucina. O gel de acrilonitrila/ácido 2-acrilamida-2- metil-1-propano sulfônico (AN/AMPS), compatível com D2O, foi testado com as moléculas sacarose e lactose. Para isto foram realizados experimentos de RMN uni e bidimensionais. A determinação do espaço conformacional das moléculas foram explorados a partir de cálculos de mecânica molecular, usando o campo de força MMFF94. O gel de (DMA/AN) compatível com acetonitrila-d3 apresentou um bom desempenho para extração de medidas de RDCs. Para a molécula de α-santonina os valores de RDCs ficaram na faixa de -14,4 a 5,4 Hz e o fator de qualidade Q de 0,011. Para a molécula de brucina os valores de RDCs variaram de -9,9 a 23,1 Hz e fator de qualidade Q de 0,047. Com esses valores de RDCs foi possível determinar a configuração relativa das moléculas testes. Os resultados usando apenas dados de RCSAs não foram adequados para a discriminação correta das moléculas, devido aos sinais serem muito alargados nos espectros de RMN de 13C. O gel de (DMA/AN) compatível com metanol-d4 apresentou um comportamento adequado para extração de RDCs com valores na faixa de -15,1 a 15,9 Hz e fator de qualidade Q de 0,069, o que possibilitou a configuração relativa correta da brucina. Porém, devido ao alargamento dos sinais nos espectros de RMN de 13C poucas medidas puderam ser extraídas e, dessa forma, não foi possível obter resultados satisfatórios de RCSAs. Por fim, o gel de AN/AMPS apresentou um bom desempenho para extração de medidas de RDCs em D2O usando as moléculas de sacarose e lactose, com valores na faixa de -9,3 a 3,5 Hz e -6,8 a 2,0 Hz, respectivamente. Com os resultados da sacarose, o fator de qualidade Q de 0,127 foi obtido para o melhor conjunto de conformações. Para a α-lactose e β-lactose os valores do fator de qualidade Q foram 0,078 e 0,089, respectivamente.

Cellulose, represented by the formula (C6H10O5)n, is a polysaccharide that can be of vegetable or microbial origin. Its bacterial production, due to its high degree of purity and properties, has potential for applications in the medical, pharmaceutical, cosmetics, food, packaging, composites industries, among others. The production of pure cellulose nanofibrils by bacteria of the genus Komagataeibacter occurs from the consumption of glucose in the medium, metabolized into cellulose by the microorganisms. In this study, the tests were divided into three stages: the first was performed using starch, present in rice and corn grains, as a carbon source for BC production. For this, the starch was hydrolyzed by fungi (Aspergillus oryzae) to obtain glucose, used for the production of BC. The results obtained showed a maximum yield of 2.80 ± 0.43 g / L of BC obtained with the hydrolyzed rice medium. In the second stage of the experiments, the production of BC was carried out using a saline solution, of its own composition, with the addition of carbohydrates and/or proteins (Glucose, Glycerol, Sucrose, Fructose, Peptone, Yeast Extract or Mannitol) as carbon sources . The maximum yield of 5.72 ± 0.01 g / L of BC was obtained with the medium containing Sucrose. In the third stage, the prototype of a sustainable package, with characteristics of a paper package, was developed. All materials produced were characterized in terms of morphology (Scanning Electron Microscopy - SEM), crystallinity (X- ray Diffraction - DRX), thermal stability (Thermogravimetric Analysis - TGA) and analysis of functional groups (Infrared with Fourier Transform - FTIR) . In the first stage of the characterizations, the FTIR confirmed the functional groups present in the BC, as well as the absence of contaminants from the production process. XRD evaluation showed crystallinity around 55%. The TGA analysis revealed that the polymers formed from the alternative media (Rice or Corn) obtained greater thermal stability. SEM showed a non-uniform structure with the random arrangement of nanofibrils. In the second stage of characterization, the diffractograms revealed a crystallinity that varied from 31% (CB-Yeast Extract) to 66% (CB-Fructose) and the FTIR analysis confirmed the existing functional groups in the bacterial cellulose, without possible contaminants. The TGA of the CB-Yeast extract and CB-Mannitol biopolymers revealed maximum degradation temperatures (Tmax.) of 350.7 oC and 322.0 oC, respectively. From the micrographs, CB-Glucose and CB-Sucrose had areas of more dispersed and visible fibrillar structures compared to the others. Finally, the characterizations of the CB-Paper used in the development of a packaging prototype presented Tmax. of 311.8 oC and crystallinity 86.42% with characteristic peaks of cellulose and calcium carbonate present in papers. In the SEM investigation, fibrous and nanometric morphology were observed together with calcite fillers. Therefore, studies like this present new culture media for the production of BC, as well as an important application for these biopolymers, in order to create alternatives to vegetable cellulose, used, for example, in the food packaging industry. 

The developed research delas with the production, characterization and determination of the properties of extruded films and injected test specimensofnanocomposites PBAT/organoclay C20A and a new hybrid composite material PBAT/clay C20A/cornstraw. The effect of incorporation and filler content on structure, thermal, rheological, mechanical, barrier, biodegradability and water sorption properties were analyzed. PBAT/C20A nanocomposites containing1, 3 and 5% (m/m) of organophilic clay and PBAT hybrid composites containing 2, 6 and 10%(m/m)ofreinforcement consisting of clay and corn straw in a 1:1 ratio were produced. After hot mixing, inatorque rheometer, the components were crushed in a knife mill and the granules were extrudedintheform of flat films and injected in the form of tensile specimens. The results show an improvement inthetensile strength of the extruded nanocomposite films with the addition of 1% clay in the polymericmatrixand of the injected systems with the addition of fillers at levels of 3% and 5%. In general, the elongationat break of composite and nanocomposite films was lower than that of injected specimens. Whenvegetable fiber is added to the polymer and clay systems, a trend of loss of tensile strength anddecreasein elongation is observed for all systems under study and an increase in the elastic modulus for injectedspecimens and a decrease for extruded films. The hybrid composite (PBAT/clay/corn straw) showedanincrease in biodegradability of 6.84% for the specimens and 3.47% for the flat films. The newhybridmaterial showed inefficiency in barrier properties, by tripling the value of O2 permeability inthefilmsample in relation to pure PBAT, making its application difficult in food packaging and protectivecoatings, but can be indicated for permeable packaging that favors the freshness of some vegetablesandmeats. It is believed that the polymer-fiber interaction effects can be improved with a better processingofthe fiber, making it smaller in sprayers in an attempt to synthesize more homogeneous films. It wasalsopossible to observe, by means of torque rheometry, a slight increase in the degradation of the systemswith the addition of loads (clay and corn straw).

Recent developments in nonlinear optical materials generally search for systems with improved second and third order optical properties, aiming at their use in optoelectronic devices, all-optical limiters, among other applications. In this context, important works focused on the exploration of new organic molecules have been published, focusing mainly on molecules with large nonlinear optical coefficients, fast response times, direct synthesis and processability. In particular, molecules with push-pull electronic structure, which give rise to the delocalization of π-electrons, present high optical hyperpolarizabilities and fast response to non-resonant excitation. Mesoionic compounds (MICs) belong to a class of materials that have great potential for nonlinear optics, as proposed more than two decades ago. Typical MICs have planar heterocyclic dipole structures in which the positive and negative charges are separated and delocalized within a π-electron system, resulting in permanent electric dipole moments that can reach 5D. In this work, we synthesize, characterize, and measure the second- and third-order nonlinearities of MICs from the 1,3-thiazolium-5-thiolate group, dissolved in dimethyl sulfoxide (DMSO) at room temperature. In measuring the second-order polarizability (first hyperpolarizability), we used the hyper-Rayleigh scattering (HRS) technique, operating at  in the nanoseconds regime. The measured hyperpolarizability,  was used to calculate the static hyperpolarizability,  by applying the classical two-level model. By the measures of the first hyperpolarizability and the calculation of the fundamental limits  we discuss the second-order optical performance of mesoionic molecules. The second-order nonlinearity of these molecules turned out to be relatively high compared to molecules of similar size. In third-order refraction and absorption measurements, we used the Z-scan technique in the picosecond (at 532 nm) and the femtosecond (at 800 nm) regimes. Under excitation at 532 nm, we observed a refractive behavior with self-defocusing, in the presence of nonlinear dissipative effects: two-photon absorption (2PA) and excited state absorption (ESA). Analysis of the results by the Fast Fourier BPM method, based on a three energy level model, revealed that the ESA cross section is one of the largest ever reported in the literature, being approximately 10 times larger than the linear absorption cross section starting from the ground state . Also noteworthy is the large value of the two-photon absorption cross section (3,7 x 10⁴ GM), consistent with previous results. Normalizing this 2PA cross section, we quantified and discussed the molecular nonlinear optical performance, which indicated a great potential for applications in all-optical limiting and all-optical switching. On the other hand, applying the Z-scan technique, operating at 800 nm, the dependence of the non-linearity with the wavelength is evidenced from the three-photon absorption excitation (3PA).

There is an increasing interest in alternatives to the sensitizers of lanthanides ions (Ln3+) for in vivo usage, especially in bio-optical applications. The transition metals (M) are good candidates as chromophores, due to their high absorption rates, and their emission bands that cover a large range of visible, and Near Infrared spectra. Despite the importance of theoretical models for the design of M-Ln3+ with higher efficiency, few works had dedicated efforts to theoretically elucidate the process of Energy Transfer (ET) between M and Ln3+ ions. In this sense, this work has the goal to adapt and apply the theory of intramolecular energy transfer developed by Malta, and collaborators to treat with ET in M-Ln3+ heterometallic complexes. Additionally, another goal is to evaluate the ET model for isotropic exchange interaction between M, and Ln3+ ions, by investigating the overlap orbital of the valence's subshell of the transition metal with the 4f subshells of the Ln3+. The overlap integrals were calculated by the coefficients of molecular orbitals for the diatomic M-Ln3+, acquired in the DFT calculations. Parameters such as the dipole strength, and the overlap spectral factor (F factor) were calculated based on the spectroscopic data available in the literature for the complexes considered. Moreover, the theoretical intensity parameters (Ωλ) were calculated by using the web application JOYSpectra. The results have shown that the exchange interaction is not relevant for typical intermetallic distances (> 5 Å) in complexes of M-Ln3+. On the other hand, the theoretical estimations of ET rates for the dipole-dipole, and dipole-quadrupole mechanisms were in reasonable agreement with the energy transfer rates observed in the systems evaluated, especially in the cases with spectral resonance (complexes of Cr-Nd, Ru-Nd). For the systems that have low spectral resonance, such as the ones with Cr-Eu, and Cr-Yb, the model was extended to consider the phonon assistance in the energy transfer process, based on the approach of Miyakawa-Dexter. The fit of the experimental data was gained for the typical values of Huang-Rhys factors of the lanthanide and Cr3+ ions. In the current stage, the model provided can be useful to predict and explain photophysical properties driven by the transfer of energy between the Ln3+, and transition metal ions.

Magnetic nanoparticles have garnered significant interest in the biomedical field due to their unique properties, such as their size being comparable to cellular structures and their ability to respond to magnetization gradients. In the medical context, these applications encompass a wide range of functionalities, ranging from their use as contrast agents to serving as vehicles for drug delivery. The primary objective of this study revolves around the synthesis and characterization of spherical and mesoporous nanoparticles of Cobalt Ferrite (CoFe2O4) and Magnetite (Fe3O4) for biomedical applications, including their role as drug delivery systems, biological sensors, and in magnetic hyperthermia therapy. The synthesis of the particles was conducted using the solvothermal method assisted by Cetyltrimethylammonium Bromide (CTAB), which acted as a templating agent, creating mesopores within the nanoparticles. The morphology of the particles was characterized using Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM), revealing the formation of mesoporous spheres with an average size of 132,49 ± 21 nm for the Cobalt Ferrite samples and 75,90 ± 12,55 nm for the Magnetite samples. Chemical composition and crystal structure characterization were performed using X-ray Diffraction, confirming the formation of an inverse spinel structure, characteristic of both Cobalt Ferrite and Magnetite materials. Furthermore, Fourier Transform Infrared Spectroscopy (FTIR) analysis revealed a peak around 580 cm-1, corresponding to the metal-oxygen bond in the Ferrite and Magnetite structures, which was further confirmed by diffraction. Drug absorption assays, based on absorbance measurements, allowed for the assessment of nanoparticle drug storage capacity. It was observed that Cobalt Ferrite nano-spheres were capable of storing 46,85% of the drug in solution, while Magnetite nanoparticles stored 36,91%. Notably, regarding drug release, significant efficiency was observed at a temperature of 43°C, with 62,68% drug release for Cobalt Ferrite particles and 88,12% for Magnetite particles. In hyperthermia assays, Cobalt Ferrite particles demonstrated efficacy as hyperthermia-inducing agents, exhibiting a temperature variation of 9,2°C. The magnetic profile of the particles was confirmed using a technique quantifying saturation magnetization values. Cobalt Ferrite particles showed potential as components of a biosensor system, evidenced by their positive response when antibodies were immobilized on them. The assay involving the conjugation of Cobalt nanoparticles with immunoglobulins and their application in lateral flow tests holds promising prospects for the development of a lateral flow biosensor.

In this study, quantum dots (QDs) of CdS, CdSe, CdTe, as well as ternary compounds of CdSxSe1-x, CdSxTe1-x and CdTexSe1-x (where x varies from 0.15 to 0.85) were synthesized by electrochemical method in a cavity cell in aqueous medium, using 3- mercaptopropionic acid (MPA) as stabilizer, pH 9 and thermal treatment of 2 hours. The electrochemical process involved a paired electrolysis, in which elemental sulfur, selenium and tellurium were reduced in a graphite powder macroelectrode, simultaneously generating S2- /Se2- ;S2- /Te2- and Te2- /Se2- ions, while a cadmium rod was oxidized, producing Cd2+ for the efficient formation of the QDs in the desired ratio. The CdSxSe1-x QDs were characterized by means of X-ray diffraction (XRD), high resolution transmission electron microscopy (HRTEM), UV-Vis absorption and emission spectroscopies, as well as cyclic and linear voltammetric analyses. The XRD analysis revealed lattice parameters that showed a linear reduction tendency as the molar ratio of sulfide increases in the crystalline structure. The HRTEM analysis allowed the determination of the nanoparticle sizes, which were 3.94 ± 0.70 nm (CdS), 4.23 ± 1.00 nm (CdS0.5Se0.5) and 4.12 ± 0.78 nm (CdSe). The band gap energy (Egopt) of the CdSxSe1-x QDs was determined by UV-Vis absorption spectroscopy and ranged from 2.42 eV to 2.84 eV, showing an increase with sulfide addition in the structure. The same behavior was observed for the Eg Elect, determined by cyclic and linear voltammetric analyses, indicating the nanoalloy nature of the ternary QDs electrosynthesized. For the CdSxTe1-x and CdTexSe1-x QDs, characterizations were performed by means of XRD and UV-Vis absorption and emission spectroscopies. The XRD analysis of CdSxTe1-x and CdTexSe1-x also revealed lattice parameters with a linear reduction tendency as the molar ratio of selenide and sulfide increased, respectively, in the crystalline structure. The Egopt of the CdSxTe1-x and CdTexSe1-x QDs presented values from 2.29 eV to 2.84 eV, and 2.30 eV to 2.83 eV, respectively. The results obtained demonstrate that the electrochemical method used allows the preparation of mixed cadmium chalcogenides with controllable properties.

We present a study of the magnetoimpedance (MI) measured in multilayer elements prepared by optical photolithography and by the sputtering deposition technique. Nanostructures are composed of layers of [Py (100 nm) / Ti (6 nm)]4 / Cu (400 nm) / [Py (100 nm) / Ti (6 nm)]4 deposited on silicon (Si), where Py (permalloy) is a magnetic alloy with composition Ni₈₁Fe₁₉ and Ti and Cu represent, respectively, metallic layers of titanium and copper. Nanostructures were made in “ribbon” geometry, a meander with two segments in the form of “U”, as well as meanders with 12 segments, one with “rectangular” vertices and another with “rounded” vertices. Hysteresis loops were obtained at room temperature (T = 298K) using a VSM type vibrating sample magnetometer (Vibrating Sample Magnetometer). The diamagnetic contribution of Si obtained, thus allowing to obtain the magnetization and magnetization of the multilayers. Values were obtained for the coercive field H_c of about 5 Oe which is typical of ferromagnetically soft alloys. Measurements of electrical impedance (Z) were also made at room temperature. The magnetic field is swept in the range of ± 4.0 kOe in both the longitudinal and transverse configurations of the samples plane. The amplitude of the Iac current was kept constant (= 2 mA) while the frequency f of the electrical current was swept from 100 kHz to 30 MHz. The MI data showed two distinct regimes. Below 5 MHz the dependence o Z with f is strongly influenced by the magnetic nanostructure and by the substrate, while above 15 MHz a resonance is observed associated with the transmission line composed of the coaxial cables, connectors and twisted pairs used. Values in the range of 5 – 40 mΩ were obtained for the maximum variation of Z relative to the value measured at 4.0 kOe whose value depends on the geometry of the nanostructure. MI was also investigated in a structure with a ribbon geometry deposited on glass in order to confirm the influence of the Si substrate and to make a comparison with data previously measured in a similar nanostructure. MI was also investigated in a structure with a ribbon geometry deposited on glass in order to confirm the influence of the Si substrate and to make a comparison with data previously measured in a similar nanostructure. For this sample, ΔZ values were much higher (~ 600 mΩ) than in the one deposited in Si (~ 40 mΩ). It is also important to note that for samples deposited on silicon there is a strong dependence of Z with f in the range from 100 kHz to 10 MHz. The dc resistance values for samples deposited on silicon were: 8.1 Ω (tape), 6.8 Ω (2-dash), 20.1 Ω (square-edged meander) and 45.2 Ω (round-edged meander). For the sample on glass, the electrical resistance was 3.2 Ω. The contribution of the Si substrate was calculated using a CPE (Constant Phase Element) model, while for the resonance associated with the transmission line, an RLC-type resonant circuit was used. Finally, the GMI results were interpreted using the model developed for planar structures with semi-infinite geometry.

In this work, sugarcane bagasse dried and carbonized in the oven at temperatures of 200, 325 and 450 °C were used as precursors of carbon dots using a solvothermal synthesis. The carbon-based fluorescent nanomaterial was tested as a fuel hydrated ethanol marker for possible fraud and adulteration prevention. In this way, the carbon spots produced were characterized by transmission electron microscopy (TEM), dynamic light scattering (DLS), zeta potential, thermogravimetric analysis (TGA), absorption, emission and infrared spectroscopies. After the synthesis, the carbon dots showed blue fluorescence. The transmission electron microscopy showed nanoparticles with a spherical or almost spherical shape with sizes in the range from 1 to 5 nm for dry sugarcane bagasse and from 1 to 3.5 nm for carbonized sugarcane bagasse. These values were different from the sizes presented by DLS, which varied from 0.8 to5,560 nm. These results associated to the zeta potential results indicated the formation of nanoparticle aggregates occurred from the sample instability. On the other hand, the absorption spectra of the carbon points produced with the dried sugarcane bagasse and carbonized in the oven at 200°C showed a single broad band, different from what is seen in the literature, but within the ranges from 200 to 400 nm related to the carbon – carbon of the aromatic nucleus transition electronic and the functional groups bonds on the surface. The emission spectra of dry and carbonized sugarcane bagasse at 200 °C presented similar intensities, but with different full width at half maximum. For the carbonized bagasse it was 110 nm while that of the dried sugarcane bagasse was 85 nm. The carbon dots obtained from carbonized bagasse at 200 °C were excited at different wavelengths and showed dependence on the excitation wavelength, shifting their maximum intensity from 425 nm to 565 nm. The infrared spectra show that high temperatures remove the groups responsible for fluorescence on the surface of the nanomaterial, decreasing the fluorescence of carbon dots for the temperatures 325 °C and 450 °C. The goals of this work were achieved, considering that the carbon dots synthesized marked the ethanol fuel using absorption and fluorescence spectra. Although, the carbon dots produced with carbonized bagasse at 200 °C could only be detected in an order of magnitude above parts per million. This is beyond the concentration limit allowed by the Brazilian National Agency of Petroleum, Gas and Biofuels (ANP). 

Heavy metal-free or non-toxic ammunition (NTA) was developed to protect the health of public safety agents and the environment. However, the methodologies used to identify the gunshot residues (GSR) of these ammunition have become inefficient. To solve this problem, the implementation of luminescent markers in ammunition was presented as an alternative. These markers are known to allow the visualization of residues at the crime scene using only an ultraviolet lamp, facilitating the visualization, sample collection and subsequent analysis of residues in the laboratory. In addition, they help to clarify the dynamics of the shooting event or even the dynamics of the crime in question. Aiming to expand the ammunition coding process and mainly a possible application in industrial scale, the present work studied the efficiency of the europium β-diketonate complex Eu(btfa)3bipy as a luminescent marker of gunshot residues. This complex was synthesized using a reflux system at 60°C, a simple and easily scalable process for industrial scale. Characterizations by infrared spectroscopy (FTIR) indicated that, in this complex, the europium ion is coordinated to β-diketonate ligands. Through photoluminescence spectroscopy (FL), the emission lines characteristics of the f-f europium transition were observed, and the antenna effect showed be the main mechanism responsible for the excitation of the sample. Thermogravimetric analysis (TGA) showed that the complex is stable up to approximately 300°C. And the Scanning Electron Microscopy (SEM) showed that the complex crystallizes into dense and irregular three-dimensional blocks. After characterization, the complex was evaluated as luminescent marker for GSR. After shots with 9mm conventional ammunition, luminescent residues (LGSR) were visualized on targets positioned at different distances (simulated victims) and on the shooter's hands. It is important to highlighted that the presence of luminescent particles on the hands of a suspect, by itself, is a strong indicator of LGSR. Furthermore, the generated residues were examined using FL and SEM, where it was possible to observe that the emission spectra showed the characteristic transitions of europium, and that the residues also presented a
morphology similar to that of the pure marker. These compositional and morphologic information are essential for the correct identification of a GSR marker. It is important to highlight that the characterization of the LGSR involved non-destructive methods of great interest for forensic investigations, since they are equipment present in the main investigative centers. The results showed that the Eu(btfa)3bipy complex is an efficient luminescent and chemical marker, and its characterization can be applied to forensic routine. 

The intrinsic resistance of plastics makes them extremely useful in many packaging applications, but they are also highly resistant to degradation and can persist for several millennia in the environment. The accumulation of plastic waste is a growing environmental problem and there is still no exact solution for this question. Biodegradable plastics are promising alternatives to conventional plastics, therefore, researches on biodegradable materials with properties that allow their application in various fields, such as packaging on a commercial scale, has been the focus of several researchers. Among these packages, active packages with microbial additives, such as essential oils, which act to inhibit or delay the growth of microorganisms in food stand out. However, depending on the polymer used for manufacturing, they can contribute to the accumulation in the environment. Thus, this work aims to study the anaerobic degradation, in sludge, of polymeric films of PBAT and PBAT added with exotic basil essential oil (OEM) during a period of 22 months. These films were analyzed by thermogravimetry, differential exploratory calorimetry and scanning electron microscopy. The quantification of the degradation was performed through the mass loss over time. As main results, it was observed that the mass loss, after 22 months, for PBAT and PBAT/OEM decreased by 4% and 22%, respectively, while the polyethylene that was used as standard showed no relevant variation. The greater mass loss can be suggested by the migration of the essential oil to the medium or by the fragmentation of the film at the time of removal from the system. About the microorganisms present in the sludge, it was observed that, at the beginning of the study, it had mostly only acid-producing bacteria, presenting, in 5 months, the Planktonic aeruginosa, and then, the Heterotrophic Anaerobic Bacteria reached the stationary phase. During the evaluation, the infiltration of oxygen in the proposed systems was confirmed, a circumstance which made possible the exponential growth of Heterotrophic Anaerobic Bacteria, making them prevalent in the biodigesters. The thermogravimetric analysis attested that the addition of exotic basil essential oil did not lead to changes in thermal degradation, with a degradation between 280 and 505 °C. For the additive films, during the degradation, it was verified an increase in the crystallization temperature and a decrease in the degree of crystallinity, due to the increase in the mobility of the polymeric chains caused by the addition of the essential oil. Through scanning microscopy analysis, it was possible to confirm signs of failure in the structure, both in PBAT and PBAT/OEM. The visualization of pores, after the study period, shows signs of degradation of the films. In view of the above, it is inferred that the essential oil did not delay the biodegradation process, thus making it viable to use PBAT/OEM films in active packaging, due to the antimicrobial and antioxidant characteristics of the essential oil incorporated.

Nanofiber scaffolds produced by electrospinning have as main characteristics the high surface area /
volume ratio and the distribution of disordered micrometric pores, which can be good candidates for
bone regeneration, facilitating cell adhesion and adsorption of organic molecules (proteins, amino acids
and polysaccharides). Among the biomaterials, hydroxyapatite (HAp) stands out for having a chemical
composition similar to bones and chemically bonding with bone tissue. The aim of this work was to
synthesize nanometric-sized HAp that could be incorporated into polyvinyl alcohol (PVA) nanofibers by
electrospinning technique. First they were synthesized by hydrothermal (HAH) and chemical
precipitation (HP), and the HP was not possible to electrospun due to the large size of the crystals.
Therefore, in order to control the size of HAp nanocrystals, we induced in situ growth associated with
alginate polymer chains and applied them as biocomposites (HAL). For electrospinning, two
concentrations of PVA solution (10 and 12%) and three concentrations of HAL (0.1, 0.25 and 0.5% (p /
w) were used for fiber preparation. Transmission electron microscopy (TEM) showed HAp similar to
rods with size in diameter and length of (10 ± 2) nm and (34 ± 7) nm, respectively. Morphological,
physical (swelling and degradation), mechanical and biological properties were evaluated and compared
with pure PVA and PVA/HAp scaffold Through the morphology analysis it can be stated that the best
parameters to form nanofibers without imperfection are those that contain 12% of PVA, however, in
membranes with a higher proportion of HAL (0.5% m/v) small surface appears quantities of agglutinated
particles of the biocomposite. We reached values of mean diameter (>110 nm) below what is observed in
the literature, even increasing the concentration of the HAL biocomposite, the values remained
approximate in most of the electrospun fibers. The best tensile strength response among electrospun
scaffold was FH2-0.1 (15.2 ± 2.5 MPa), although the other membranes also present high limits of
mechanical strength. Swelling and degradation rates were estimated weekly in vitro in PBS solution for a
period of 04 weeks. In vitro tests were also applied to assess the biocompatibility of the material studied.
Three cell lines were used in the study of the cell viability of the scaffolds and ceramic powders. In this
assay all samples had satisfactory results in the quantification of viable cells. As for the cell adhesion test
in the FH2-0.1 scaffold, it showed that human gingival fibroblast cells (FGH) adhere and proliferate on
the surface. These and other properties are fundamental conditions to show that these materials have

great potential for applications in bone tissue.

This work provides low-cost and sustainable biopolymer gel electrolytes, which are based on seawater (3.5 % NaCl), for application in supercapacitors of active porous carbon. The bio-polymer agar-agar is modified with basic solution NaOH to increase the viscosity performance in 21 folds (82 Pa.s), compared to commercial agar-agar (3.86 Pa.s). This improvement occurs due to an open ring of agar molecule, which favors the formation of cohesive super-fibers in the electrolyte. The electrolytes show improved electrochemical behavior due to the doping of agar-agar with imidazolium ionic liquids. In this regard, ionic conductivity and electrochemical window stability determine the synthesis parameters through the Design of Experiments (DoE).  Despite the highest viscosity, the electrolyte increased the ionic conductivity, when it is compared to the modified agar-agar with the commercial one. It occurs because of the better iteration between agar-agar and the Na+ e Cl-  ions with polymer chain, which favor the conduction by ion jump. The ionic liquids improved the transport properties because of increasing the ion jump and also decreasing the relaxation time of the polymer chain (plasticize effect). Thus, supercapacitors with optimized electrolytes are manufactured with a capacitance, energy, and power density between 2.5-11 F.g-1, 0.4-1.8 Wh.Kg-1, and 117-2565 W.Kg-1, respectively, depending on the applied scan rate (cyclic voltammetry) and density current (galvanostatic charge-discharge). Therefore, the results indicate electrolytes that favor the large-scale production of sustainable supercapacitors. Thus, this work solves the social demand for eco-friendly technologies for energy storage.

In this work, synthetic routes were presented to obtain luminescent materials, presenting polymorphism, obtained by the same precursor materials under magnetic stirring, at different temperature parameters. A zwitterion 3-(1methylimidazolium-1-yl) butane-1-sufonate as a ligand was mixed with Eu³⁺ ion at room temperature for 24 hours to obtain the EuZ_gel system and at 80 ºC for 12 hours to obtain the EuZ_crystal system. Their chemical, structural and photophysical properties were sequentially analyzed to apply them as latent fingerprint (IDL) revealing agents.

Through elemental analysis, the minimum formula 2(N₂C₄H₄).3(SO₃).(NEu).9H₂O was proposed for both systems. The purity and preservation of the zwitterion structure was estimated through the displacement signals by Nuclear Magnetic Resonance (NMR). The structural investigation of the EuZ_gel and EuZ_crystal compounds started with the Infrared technique (FTIR), in which bands were identified at 3500 cm^-1 corresponding to the OH group, which proved to be wider for the extended system, when compared to the solid system, and also, indicative of coordination by the S=0 terminal, with signals between 1009 – 1294 cm^-1 for the two synthesized materials. Such events were confirmed by the use of the Raman scattering technique. The new crystalline profile was identified through x-ray diffractogram for the EuZcristal system, as well as the gel character of the EuZgel system identified by rotational and oscillatory rheology techniques, inferring on the solid behavior of the system superior to the liquid character present.

The thermal stability of the materials was analyzed by thermogravimetry and significant degradation changes were noticed from 270 ºC, with the degradation of the butyl chain present in the organic structure of the zwitterion, generating residues by thermal effect at approximately 650 ºC for the EuZ_gel system and 900 °C for the EuZ_crystal system. The phase transformation that occurred from the gel to the crystal was identified by differential scanning calorimetry (DSC), identifying the crystal formation temperature around 232 ºC, with the intermediate transformation steps monitored by Scanning Electron Microscopy (SEM). The systems had their spectroscopic identities explored, by the technique of absorption in the ultraviolet-visible region, band centers were assigned at 214 nm; 288 nm and 301 nm for Eu_Zcrystal; zwitterion and EuZ_gel, respectively. And through the excitation of the systems at 395 nm, photoluminescence spectra were obtained, monitoring the emission at 615 nm (⁵D₀→⁷F₂) and estimated lifetimes in the excited state in the order of 0.23 ms for the gelled system and 1, 53 ms for the crystalline system. The theoretical study about the geometry around the central ion (Eu³⁺) was carried out by calculating the excited states by the Luminescence Package (LUMPAC) and the three-dimensional geometric coordination optimized by the Recife Model 1 (RM1) program.

Knowing the thermal and chemical properties of the materials obtained, combined with the luminescence profile studied, the systems were simultaneously applied as latent fingerprint revealing agents, using a whorl pattern print, with previously identified characteristic points. Sixty fingerprints were collected on glass slides, where half of them were submitted to development by EuZ_crystal material and the other half, transferred to collection tape, for deposition in the form of EuZ_gel system film, corresponding to 30 days of monitoring of the impressions. These papillary records showed the efficiency of the compounds in the performance of the elucidation of papillary lines over time, with luminescent and visual efficiency until the 10th day of collection for the gel phase enhancer and efficiency until the 30th day in the use of the system in the crystalline phase.

Caracterização de filmes poliméricos: DRX, Ensaio mecânico e FTIR (PCA)

In this work, we approach the preparation and characterization of nanostructured materials and their application in different areas, such as contaminant removal, DNA extraction and purification, supercapacitor, and sensing of the Leishmania pathogen. Initially, we synthesized the magnetic nanocomposite (MNC) of iron oxide/chitosan/polyaniline (γ-Fe₂O₃/Chi/Pani), which was properly characterized by Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), magnetization curves and X-ray diffraction (XRD). This nanocomposite was then applied to remove dyes (methyl orange (AM), indigo carmine (IC) and rhodamine B (RB)) dispersed in an aqueous medium. For this, we analyzed the effect of variations in parameters such as the pH value of the medium, the dye concentration and the interaction time, which allowed us to adjust the data to different models used in the description of the isotherms and the kinetics of the process of adsorption of contaminants. When using 2 mg of MNC, the adsorption capacity was 147 mg for AM, 126 mg for IC, and 80 mg for rhodamine, values considered promising compared to the performance of other adsorbent materials described in the literature. We also examined the influence of temperature variation on adsorption, which allowed us to establish that the process occurs spontaneously and is endothermic in nature. This same nanocomposite was also used to extract DNA from samples of a complex nature, such as human blood. In this step, different parameters were optimized, such as the amount of MNC to be used, the volume of adequate buffer solution to promote desorption, and the results obtained were then compared with those resulting from the use of commercial kits based on column systems (membranes) and particles. Still during the doctorate, we started two additional lines of work in parallel. The first concerns electrodes for energy storage devices based on eggshell membranes (MCO) that were demineralized and subjected to an ultrasonic tip with the subsequent incorporation of carbon nanostructures (NEC) as multilayer carbon nanotubes (MWCNT), and then the addition of poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT: PSS). Here, our objective was to improve the electrical conduction and energy storage properties by the phenomenon of electrical double layer (EDC) and pseudocapacitance (PsC), in energy storage devices such as organic supercapacitors. The second project was aimed at the development of a platform formed by a functionalized glass substrate and gold nanoparticles (NPs) that can be used for diagnostic tests. For this, we implemented functionalization studies of glass substrates by the vapor-phase deposition of thiolated and amine groups, which were then placed to interact with gold NPs to form nanostructured films. Through spectroscopy in the ultraviolet and visible region (UV-Vis) and scanning electron microscopy (SEM-STEM) it was possible to follow the steps. Next, we performed proofs of concepts for the detection of nucleic acid through the immobilization of thiolated probes of DNA from the Leishmania infantum pathogen, which demonstrates the potential of this research.

Graphite sheets (GS) have interesting properties, such as high mechanical strength, electrical conductivity, and surface stability, in addition to being produced on a large scale at a low cost. In this thesis, graphite sheets were used as conductive substrates for the electropolymerization of phenothiazine dyes, methylene blue (MB), and toluidine blue (TB), aiming at the development of electrochemical sensors. Electropolymerization was performed by cyclic voltammetry, and it was observed that the switching potential strongly influences the electropolymerization of MB. The switching potential of 1.2 V (Ag/AgCl) resulted in greater roughness of the electropolymerized film. The poly(methylene blue) (PMB) film deposited on the surface of GS increased the sensitivity to nitrofurantoin (NFT) and minimized electrode fouling. The GS/PMB exhibited a linear response range from 5 to 100 μmol L-1, with a detection limit of 55 nmol L-1 . The proposed sensor has been successfully applied for NFT quantification in urine and tap water samples. For the electrode modified with poly(toluidine blue) film (PTB), an improvement in analytical performance was observed when potential cycles in KOH 0.1 mol L-1 were performed after the film growth step. This procedure also resulted in flat and more compact films. The developed sensor showed an increase in sensitivity for tryptamine (TRYP) determination, lower detection limit, and it was less susceptible to the electrode deactivation during TRYP electrooxidation. The GS/PTB-KOH electrode exhibited a linear range from 0.05 to 0.9 μmol L-1 and a detection limit of 12 nmol L-1 allowing for the quantification of TRYP in cheese samples. Model analytes such as procaine (PRO) and lidocaine (LID) were also evaluated to explore the applicability of the sensor and improved sensitivity and lower detection limits were observed. The electropolymerization of phenothiazine dyes in graphite sheets proved to be a promising strategy for fast and inexpensive analysis using a disposable electrode for sensing different analytes.

Light emissions by upconvertion are processes in which lower energy photons are converted into higher energy photons. For example, excitation in the near infrared (NIR) region causes emissions in the visible region. These processes have several applications ranging from photovoltaics and lighting to nanomedicine, which arise great interest. In the last decade, a bright white light emission with a continuous spectrum was observed when exciting some materials, in particular, metal oxides, with high power density (laser) sources at the NIR region. The origin of this phenomenon is not yet established, which is the motivation for the development and implementation of a quantitative model. This model was based on the power balance equation in which the energy absorbed from the excitation beam is dissipated by heat transfer (thermal conduction), by internal heating (thermal capacity) and by thermal emission of white light (blackbody type). The numerical solution of the differential equation obtained in the model was successfully implemented and provided results without the approximations used in the analytical solutions. Thus, the temporal dependence of temperature and of the continuous broad bright white light emission by energy upconversion in (nano)materials were obtained and compared with experimental observations and data. All the main features of these continuous bright white light emissions were explained and quantified by the analytical and numerical results. In particular, the dependence of the integrated emission intensity on excitation source power, on the particle size and sample porosity and doping, on the ambient pressure and temperature, as well as the existence of a power density threshold of the excitation source and the non-exponential temporal decay of white light emission. It has been shown the reasons for the white light emissions obtained by upconversion are so bright and so intense, similar to incandescent bodies. The results obtained and their comparisons with experimental data suggest that the proposed model has been validated and describes quantitatively all the features of this process, and can be used to design new, more efficient materials and improve experimental conditions.

New materials are being developed to replace those that contribute to the accumulation of plastic
in my environment, such as the use of biodegradable polymers to produce plastic packaging.
PBAT (polybutylene adipate co-terephthalate) is a biodegradable polymer and can be used for the
manufacture of active packaging, technology that aims to extend the shelf life of the food,
ensuring the quality of the same. As a promising additive to this packaging we have the essential
oil of thyme, which adds desirable properties by having antimicrobial properties and eliminates
the use of chemical preservatives. Thus, the present work evaluated the effects of the essential oil
of thyme on the properties of poly (butylene adipate co-terephthalate), analyzing the antimicrobial
activity, physical, mechanical and thermal properties of PBAT active packages formulated with
essential oil of thyme, (FTIR), traction test, differential scanning calorimetry (DSC), and
thermogravimetric (TGA) analysis were performed using diffusion disc, Fourier transform
infrared spectroscopy (FTIR) techniques. The films were prepared by solvent casting with
different concentrations of oil (1, 2, 5, 10, 15 and 20%). Thyme oil had the concentrations of
52.16% o-cymene, 28.21% thymol and 13.26% carvacrol. The films presented bands
characteristic of both PBAT and oil, but in the films added it was necessary to perform the PCA
of the FTIR spectra to show the incorporation of the oil in the polymer matrix, which resulted in
five different groups. The oil presented antimicrobial activity against E. coli and S. aureus.
Regarding the mechanical properties, there was a reduction of the tension in the majority of the
samples added with oil, more pronounced in the samples with 15% of oil. As for the elastic
modulus, the samples with 20% oil showed a greater drop in stiffness, thus being more flexible

than the others. In the thermal properties (temperature, enthalpy and degree of crystallization and
melt temperature) they remained practically constant with the addition of the oil as well as the
stability and thermal degradation resembled the pure PBAT film. With these results, the PBAT
films incorporated with thyme essential oils showed to be promising for use as perishable food
packaging, also contributing to the reduction of conventional plastic.

O acesso as informações em documentos históricos são de interesse da humanidade nos
vários ramos das ciências. Muitos desses documentos estão em estágios de degradações muito
avançados e o seu manuseio coloca em risco a sua integridade física. Assim, o acesso as
informações neles contidas fica impossibilitado e vastas coleções de documentos aguardam o
surgimento de uma técnica que permita recuperar essas informações.
Apenas de no âmbito internacional tentativas para solucionar essa impossibilidade têm
sido feitas em poucos centros de pesquisa, o nosso trabalho busca contribuir com essa questão
propondo uma técnica para recuperação das informações contidas em documentos históricos
que estão na forma física de rolos ou espiralados e que foram escritos com tinta ferrogálica,
através de uma metodologia inédita e fazendo uso de dados gerados por algoritmos
desenvolvidos em softwares livre e em associação com o uso de softwares proprietários que
aplicada no imageamento gerado pelo micro tomógrafo de raios X permitem revelar
virtualmente a deposição da tinta ferrogálica sobre o suporte.
Na sequência metodológica demonstramos ser possível associar a quantidade da tinta
virtualmente revelada pela tomografia e a sua paridade com caracteres tipográficos ou
pictóricos. Para tanto produzimos a planificação ou desenrolar virtual dos documentos
possibilitando assim a recuperação das informações desses documentos históricos através da
leitura das páginas virtualmente produzidas.
Os resultados obtidos até a presente data são promissores para a recuperação das
informações em documentos históricos antes inacessíveis.

Currently, there is a significant demand for new materials capable of removing contaminants, such as organic compounds and heavy metal ions, from aqueous media, to allow the proper disposal of wastewater without causing damage to public health and the environment. At the same time, the appearance of varieties of antibiotic resistant pathogens is an emerging problem. Multidrug-resistant strains of Escherichia coli deserve special attention in human and veterinary medicine worldwide, due to the possibility that the ingestion of water and food contaminated by some of them will cause serious damage, given the possibility that they will accumulate resistance genes for extra-intestinal survival. In this thesis, we describe the preparation of polymethylmethacrylate/(rice husk ash)/polypyrrole (PMMA/CCA/ PPi) composite membranes and they are used as an active agent for the removal of hexavalent chromium (Cr (VI)) and the dyes tartrazine organic (E102) and indigo carmine (IC) dissolved in aqueous solutions. At pH 2, the PMMA/CCA/PPi membranes showed good removal capacity for all three contaminants analyzed, with values (qe; t) equal to (360.5 mg/g; 150 min), (165.7 mg/g; 60 min), and (142.9 mg/ g; 70 min) for Cr (VI), E102 and IC, respectively, where qe is the adsorption capacity and t the saturation time. We also investigated the antimicrobial activity of polymethylmethacrylate/chitosan/(silver nanoparticles) (PMMA/Qui/NPAg) membranes against the pathogenic E. coli DH5-α strain, when their high bactericidal performance was demonstrated. Thus, we suggest that these membranes present themselves as promising materials for application in efficient water remediation protocols, by combining a relatively simple preparation methodology and, respectively, a high adsorption capacity for different types of contaminants and bactericidal capacity for use as an active agent in microbiological filtration systems.  

Desde a antiguidade o ser humano realiza medições e com a evolução da tecnologia e da Ciência, as medições se tornaram ainda mais evidentes e relevantes. Sendo assim, a discussão sobre as medidas e os resultados apresentados sempre foram alvos de incertezas, uma vez que associados aos resultados, as incertezas também estão presentes. Nesse seminário, iremos discutir os principais conceitos sobre as incertezas de medição, e também iremos esclarecer as principais diferenças entre os erros e as incertezas. Além disso, apresentaremos as principais fontes de incertezas, os princípios das incertezas e as principais etapas para a determinação das incertezas. Será apresentado um exemplo prático de como determinar e expressar essas incertezas nos resultados experimentais. Finalmente, será apresentada uma reflexão, sobre a importância de determinar essas as incertezas nas tomadas de decisões e aceitação das grandezas apresentadas.