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Produção de biochar a partir de resíduo agroindustrial da macaúba (Acrocomia aculeata), caracterização e avaliação de sua capacidade de adsorção na remoção de contaminantes

Fri, 12 Dec 2025 00:00:00 GMT

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

Desenvolvimento de índice e ferramenta geoespacial para análise da integridade ecológica em nascentes do cerrado brasileiro

Tue, 01 Jul 2025 00:00:00 GMT

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

Plataformas eletroquímicas baseadas em material carbonáceo modificadas com estruturas híbridas: da construção à determinação de moléculas de interesse alimentício, ambiental e clínico

Wed, 09 Apr 2025 00:00:00 GMT

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

Reações do piridoxal com cetonas: síntese de 1,3-diidrofuro[3,4-c]piridinas e derivados

Thu, 02 Apr 2020 00:00:00 GMT

Título: Reações do piridoxal com cetonas: síntese de 1,3-diidrofuro[3,4-c]piridinas e derivados Autor(es): Casadia, Izamara Primeiro Orientador: Pizzuti, Lucas Abstract: Pyridoxal is one of the natural free forms of vitamin B6 and plays important roles in living systems. Although a low molecular weight molecule, pyridoxal has several functional groups. Therefore, it is an excellent starting material in organic synthesis. Most works explore the reactivity of carbonyl in order to prepare imines and hydrazones in order to mimic biosynthetic processes. However, a study on the Claisen-Schmidt condensation reaction between pyridoxal and ketones has not been found in the literature. In this sense, synthetic changes were made to the pyridoxal in order to obtain series of unprecedented molecules with potential applications in coordination chemistry and for the evaluation of biological activities. It were obtained from the furo[3,4-c]pyridine with yields ranging between 53 and 90% by aldol condensation reaction of Claisen Schmitd followed by oxaMichael addition among pyridoxal and enolizable ketones. In a second step, hydrazones were obtained by reacting furopyridine with different hydrazine derivatives. Finally brominations were carried out on furo[3,4-c]pyridines to prepare useful intermediates for future work involving coupling reactions. The products obtained in pure form were characterized by infrared spectroscopy, high resolution mass spectrometry, melting point, 1H NMR and 13C NMR and presented data consistent with their structures. Editor: Universidade Federal da Grande Dourados Tipo: Tese