http://repositorio.ufgd.edu.br/jspui/handle/prefix/513 2026-07-24T00:55:56Z http://repositorio.ufgd.edu.br/jspui/handle/prefix/6814 Título: Efeito dos modificadores mistos nas propriedades elétricas de vidros CaNaBO avaliado por espectroscopia de impedância Autor(es): Prado, Esmael Dias Primeiro Orientador: Souza, Seila Rojas De Abstract: Borate glass matrices based on boron oxide have lower melting points than silicate glasses, facilitating their preparation and reducing production costs. Boron oxide forms various structural units, allowing the incorporation of dopants such as rare-earth elements and transition metals, enabling the development of heavy-metal-free materials. The incorporation of ions such as Na+ into glass matrices meets the demand for environmentally friendly and biocompatible alternatives in energy storage technologies. Additionally, the amorphous structure of glasses offers advantages over other electrolytes, including isotropic ionic conductivity and the absence of grain boundary effects typical of ceramics. To evaluate the electrical properties of glass samples formed by boron oxide (B₂O₃) as a network former and modified with calcium oxide (CaO) and sodium oxide (Na2O), compositions of (33.33-x)CaO − xNa2O − 66.67B2O3 with x = 5, 10, 15, 20, 30, and 33 mol% were investigated and designated as CaNaBO-x. X-ray diffraction (XRD), Differential thermal analysis (DTA), UV-Vis spectroscopy, and impedance spectroscopy (IS) were employed. XRD and DTA confirmed the amorphous nature of the samples, while UV-Vis measurements revealed transmittance above 80% between 342 and 1000 nm. Impedance spectroscopy measurements, conducted between 50 and 425 °C, showed that at 300 °C the electrical conductivity varied from approximately 10−13 S/cm for CaNaBO-05 to 10−6 S/cm for CaNaBO-33, corresponding to a variation of about seven orders of magnitude. The DC conductivity was fitted according to Jonscher’s Power Law, and the apparent activation energy ( ), obtained from the Arrhenius model, decreased from 154 to 87.5 kJ/mol, suggesting that the substitution of Ca2+ by Na+ enhances ionic mobility, although showing a tendency toward non-linear compositional behavior at higher Na₂O contents. These results highlight the potential of the borate glass system for advanced studies of ionic conductivity and complex dielectric relaxation mechanisms. Editor: Universidade Federal da Grande Dourados Tipo: Tese 2024-11-04T00:00:00Z http://repositorio.ufgd.edu.br/jspui/handle/prefix/6769 Título: Produção de biochar a partir de resíduo agroindustrial da macaúba (Acrocomia aculeata), caracterização e avaliação de sua capacidade de adsorção na remoção de contaminantes Autor(es): Maachar, Anderson Fialho Primeiro Orientador: Muzzi, Rozanna Marques Abstract: This work reports the production of biochar at different temperatures, using a simplified and low-cost procedure, aiming to obtain an adsorbent capable of removing pollutants in aqueous solutions; Methylene Blue (MB) and the Emerging Contaminant (EC) Bisphenol A (BPA) were tested. Biochars were produced from the carbonization of biomass at temperatures of 300 ºC (BC-300), 400 ºC (BC-400), 500 ºC (BC-500), 600 ºC (BC-600), 700 ºC (BC-700), and 800 ºC (BC-800), for 2 hours, in a standard electric muffle furnace, without purge and under limited oxygen conditions (non-inert atmosphere), with no pre-treatment, post-treatment or activation. The precursor used was Macaúba (Acrocomia aculeata) endocarp (EDP), a lignocellulosic material with physical and chemical characteristics favorable to carbonization, besides being accessible and low-cost. The changes in the physical and chemical properties of the precursor biomass and the differences between the biochars themselves were evidenced by TG/DTG, SEM, FT-IR, and XRD analysis and characterization techniques, thus confirming the influence of temperature on the biomass transformation. The results obtained for gravimetric yield (ηG) and the adsorption capacities of MB (qe-MB) and BPA (qe-BPA) were submitted to two-factor Analysis of Variance (ANOVA-2), followed by the Tukey test (p<0.05). The ηG produced under these conditions ranged from 11.05% to 35.98%, and there was a significant influence of the interaction between the evaluated factors (Carbonization Temperature x Atmosphere Condition), whose levels were 6 (six) temperatures between 300 ~ 800 ºC and 2 (two) conditions With Lid (CT) and Without Lid (ST); the CT method presented better yields at all tested temperatures. All biochars produced were able to remove MB and BPA, with better results for MB removal – for which qe-MB ranged from 5.37 to 35.13 mg.g-1 and qe-BPA from 0.92 to 23.17 mg.g-1; a significant interaction of the evaluated factors (Type of Adsorbent x Adsorbent Concentration) was observed; there were 7 (seven) levels for the types of adsorbents (EDP and the biochars) and 4 (four) levels for adsorbent concentrations (between 0.25 and 1.00 g.L-1) for the MB trials, while for BPA trials there were 5 (five) levels – between 0.50 and 5.00 g.L-1; for all tested adsorvates, BC-700 and BC-800 were superior to the others. Complementarily, BC-700 and BC-800 were submitted to textural characterization via N2 adsorption and exhibited maximum adsorbed quantity of 81.89 cm3.g-1 and 69,34 cm3.g-1, respectively; BC-700 was also superior in terms of specific BET surface area with 189.72 m2.g 1and BC-800 with 137.51 m2.g-1. The isotherms obtained for both materials exhibited shapes and hysteresis loops characteristic of mesoporous materials with a significant fraction of micropores. However, it was observed that with this low-cost and simplified carbonization method of Macaúba EDP, it is possible to produce, with yields equivalent to other methods, adsorbents capable of removing MB and BPA in aqueous solution; with those carbonized at the highest temperatures, 700 ºC and 800 ºC, being the most efficient, with BC-700 slightly better. Editor: Universidade Federal da Grande Dourados Tipo: Tese 2025-12-12T00:00:00Z http://repositorio.ufgd.edu.br/jspui/handle/prefix/6527 Título: Desenvolvimento de índice e ferramenta geoespacial para análise da integridade ecológica em nascentes do cerrado brasileiro Autor(es): Lobtchenko, Julio Cesar Pereira Primeiro Orientador: Arruda , Eduardo José de Abstract: The Brazilian Cerrado, a biome of recognized importance for biodiversity conservation and water regulation, is under intense anthropic pressure, especially due to agricultural expansion and environmental fragmentation processes. Given this scenario, this thesis aimed to propose, test, and validate an Ecological Integrity Index (EII) specific to spring areas, using remote sensing data obtained by multispectral drones. In addition, a geospatial plugin for QGIS was developed, capable of operationalizing the entire EII calculation flow, spatial analysis, and automated generation of maps and reports. In Chapter 1, the methodology for constructing the EII was structured, based on the integration of the spectral indices NDVI, NDWI, PSRI, BSI and CHM, synthesized via Principal Component Analysis (PCA). The statistical validation demonstrated strong consistency between the indices, with emphasis on NDVI and NDWI, which presented greater explanatory power in the spatial variability of ecological integrity, according to GeoDetector analyses and Spearman correlation. The application of the EII revealed that the analyzed springs mostly present conditions of low to critical ecological integrity, with emphasis on springs N01, N02 and N06, which exhibited indices below 0.40, reflecting a high degree of degradation. On the other hand, spring N05 maintained moderate integrity (0.504), although with alert zones. Chapter 2 details the development and validation of the GeoFlow plugin, a computational tool that integrates the entire EII processing flow within QGIS. The plugin allows for everything from pre-processing of images to generating final maps, statistical analyses and automatic reports. Performance tests have shown that the plugin significantly reduces processing time, increases scientific reproducibility and allows its use by users without advanced programming knowledge. The functionalities were validated in the same spring areas, confirming the spatial patterns detected in Chapter 1. In general, the results of this thesis confirm that EII is a robust, sensitive and applicable tool to the reality of Cerrado springs, and that its implementation via plugin represents a significant advance in the democratization of geotechnologies applied to environmental monitoring. The proposed approach proves to be scalable and adaptable to other regions and biomes, strengthening environmental management based on high-precision data. Editor: Universidade Federal da Grande Dourados Tipo: Tese 2025-07-01T00:00:00Z http://repositorio.ufgd.edu.br/jspui/handle/prefix/6330 Título: Plataformas eletroquímicas baseadas em material carbonáceo modificadas com estruturas híbridas: da construção à determinação de moléculas de interesse alimentício, ambiental e clínico Autor(es): Oliveira, Igor Gabriel Silva Primeiro Orientador: Martelli, Silvia Maria Abstract: In this work, a lab-made sensor was constructed and printed on polyethylene (SPE) and optimized with graphite conductive ink and stained-glass varnish (70%/30%), demonstrating good reproducibility, stability, and excellent electroactivity. The constructed electrochemical devices exhibit robustness and practicality in terms of the defined chemical modifications for diverse applications across various sample classes. Using the SPE platform, modified systems were developed with Au nanoparticles, polymers (chitosan, poly-beta-cyclodextrin, poly-L-cysteine, polyaniline), Printex L6 carbon, deep eutectic solvent, and enzymes. These modified electrodes enabled the detection of various analytes in a wide range of sample types, including estriol (LOD: 1.88 µM), catechin (LOD: 2.52 nM), theobromine (LOD: 0.076 µM), folic acid (LOD: 0.018 µM), and phytic acid (LOD: 0.8 µM). The platforms demonstrated high sensitivity, selectivity, and applicability in diverse matrices across environmental (river water, tap water), food (teas, cocoa products, spinach leaves), and clinical (saliva, blood, sweat, urine) fields. These sensors stand out as sustainable and effective alternatives to traditional analytical separation and quantification methods. The results presented in this study advance the frontier of knowledge in electrochemical sensing for environmental, clinical, and food monitoring applications. Editor: Universidade Federal da Grande Dourados Tipo: Tese 2025-04-09T00:00:00Z