http://repositorio.ufgd.edu.br/jspui/handle/prefix/513 2026-09-07T11:06:51Z 2026-09-07T11:06:51Z França , Roberta Sorhaia Samayara Sousa Rocha de http://repositorio.ufgd.edu.br/jspui/handle/prefix/7048 2026-09-04T05:30:13Z 2026-08-11T00:00:00Z

Título: Desenvolvimento de tecnologia magnética de baixo custo para remoção de microplásticos usando Luffa Cylindrica Autor(es): França , Roberta Sorhaia Samayara Sousa Rocha de Primeiro Orientador: Muzzi , Rozanna Marques Abstract: Microplastics in the environment are becoming ubiquitous, and their widespread distribution in aquatic environments poses a global environmental concern. Given the rising trend of this contamination, it is necessary to develop removal technologies that combine efficiency with low cost. In this context, adsorption combined with magnetic separation emerges as a promising strategy, as it enables both the capture of microplastics (MPs) and the recovery of the adsorbent from the aqueous medium. Thus, this study aimed to develop and evaluate a magnetic bioadsorbent—designated LCMAGNaOH—composed of Luffa cylindrica (LC) fruit (commonly known as vegetable sponge) modified with NaOH and combined with natural micrometric magnetite (MAG), for the removal of polystyrene (PS) and polyethylene terephthalate (PET) microparticles. Synthesis was carried out without organic solvents and at temperatures below 100 °C. The resulting material was characterized using physicochemical and morphological techniques—including scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR), and X-ray diffraction (XRD)—to assess its morphology and confirm the presence of the magnetite phase. The removal efficiency of LCMAGNaOH was evaluated using PS and PET MPs ranging from 75 to 600 µm in size across three aqueous matrices: drinking water, simulated seawater, and water collected from a eutrophic lake in Dourados, Mato Grosso do Sul, Brazil. Tests were conducted with short contact times and without continuous agitation, and residual MP concentrations were determined via ultraviolet-visible (UV-Vis) spectroscopy and gravimetry. Additionally, the stability of the magnetic phase, the recovery of the bioadsorbent via magnetic separation using a neodymium magnet, and its reusability over three cycles were evaluated. LCMAGNaOH demonstrated high removal capacity with a short contact time, achieving approximately 82% for PS and 81% for PET within 10 minutes. Magnetic separation also enabled the recovery of over 90% of the material mass, demonstrating the feasibility of its removal from the aqueous medium after treatment. The results show that LCMAGNaOH is an efficient magnetic bioadsorbent for capturing microplastics in various aqueous matrices, representing a promising strategy for microplastic removal in aquatic environments.magnetic separation, representing a promising strategy for microplastic removal in aqueous environments. Editor: Universidade Federal da Grande Dourados Tipo: Tese

2026-08-11T00:00:00Z Silva , Fabrícia Rilenne de Sousa http://repositorio.ufgd.edu.br/jspui/handle/prefix/6957 2026-08-27T05:29:16Z 2026-07-23T00:00:00Z

Título: Métodos biofotônicos no monitoramento dos mecanismos de ação do benzo[a]pireno no aparato fotossintético da macrófita aquática Lemna minor L. (Araceae) Autor(es): Silva , Fabrícia Rilenne de Sousa Primeiro Orientador: Botero, Eriton Rodrigo Abstract: Polycyclic Aromatic Hydrocarbons (PAHs) are organic contaminants widely distributed in the environment, among which Benzo[a]pyrene (BaP) stands out due to its persistence and toxicological relevance. This study evaluated the effects of BaP on the photosynthetic apparatus of the aquatic macrophyte Lemna minor L. using biophotonic methods based on optical spectroscopy and chlorophyll a fluorescence. The research comprised in vitro and in vivo assays employing Synchronous Fluorescence Spectroscopy (SFS), Excitation-Emission Matrices (EEMs), Pulse-Amplitude Modulated fluorescence (PAM), fluorescence imaging, OJIP Transients, and Laser-Induced Chlorophyll Fluorescence (LICF). SFS enabled the characterization and quantification of BaP both as an isolated standard and in a PAH mixture, with Δλ = 40 nm providing the best spectral definition. In the in vitro assays, increasing BaP concentrations progressively quenched chlorophyll fluorescence, indicating an interaction between the contaminant and the fluorescent system. In the in vivo assays, BaP exposure altered the F₀, Fm, Fv/Fm, NPQ, and Rfd parameters, indicating progressive impairment of photosynthetic efficiency and vitality in L. minor. The OJIP curves revealed changes in the O-J, J-I, and I-P phases associated with QA reduction, electron transfer between QA and QB, the redox state of the plastoquinone pool, and subsequent stages of electron transport. The biophysical parameters derived from the JIP test showed increased energy dissipation and reduced photosynthetic performance over the exposure period. Laser-induced fluorescence analyses revealed changes in the emission bands near 680 and 735 nm, with more pronounced alterations in the F₆₈₀/F₇₃₅ ratio after 72–96 h, indicating late photosynthetic impairment. Overall, the results demonstrate that BaP progressively alters the dynamics of energy utilization, transport, and dissipation in the photosynthetic apparatus of L. minor, and that biophotonic methods constitute complementary, non-destructive tools for linking contaminant exposure to photophysiological responses in aquatic photosynthetic organisms. Editor: Universidade Federal da Grande Dourados Tipo: Tese

2026-07-23T00:00:00Z Oliveira, Paula Luiza Antunes de http://repositorio.ufgd.edu.br/jspui/handle/prefix/6905 2026-08-18T05:11:36Z 2025-08-06T00:00:00Z

Título: Potencial Antifúngico de Bioinsumos: Aplicações de Óleos Essenciais e Líquido da Casca da Castanha de Cajú na Preservação de Frutas Autor(es): Oliveira, Paula Luiza Antunes de Primeiro Orientador: Martelli, Silvia Maria Abstract: The antifungal potential of natural bioinputs, such as essential oils and cashew nut shell liquid (CNSL), has emerged as a sustainable and effective alternative for controlling phytopathogenic fungi and preserving tropical fruits post-harvest. The growing demand for natural, safe, and environmentally responsible foods drives the search for innovative strategies to replace the intensive use of pesticides and chemical preservatives, whose continuous application causes environmental impacts, human health risks, and promotes the emergence of resistant microbial strains. In this context, essential oils from clove (Syzygium aromaticum), peppermint (Mentha piperita), tea tree (Melaleuca alternifolia), and babassu oil (Attalea speciosa), as well as CNSL, have shown promise due to the presence of bioactive compounds capable of inhibiting fungal growth, exhibiting low toxicity, and being biodegradable, constituting ecologically responsible and economically viable alternatives. The main objective of this thesis was to evaluate the antifungal potential of these bioinputs against Aspergillus sp. and Colletotrichum gloeosporioides, as well as to assess their effectiveness when incorporated into biodegradable coatings for the preservation of guavas (Psidium guajava L.). The specific objectives included investigating the inhibitory action of essential oils and CNSL on the selected fungi; evaluating the performance of carboxymethylcellulose (CMC) and pectin-based coatings containing these compounds in preserving the physicochemical, microbiological, and sensory attributes of the fruits; and discussing the feasibility of using bioinputs as sustainable alternatives to conventional conservation and phytosanitary control methods. Article 1, titled “Antifungal Efficacy of Essential Oils (Clove, Peppermint, Tea Tree, Babassu) and Cashew Nut Shell Liquid against Aspergillus sp. and Colletotrichum gloeosporioides,” investigated the antifungal activity of essential oils and CNSL through in vitro assays, including minimum inhibitory concentration, conidial germination, and mycelial growth inhibition. Clove essential oil demonstrated the highest efficacy, showing fungicidal potential even at low concentrations, followed by peppermint and tea tree oils, which primarily acted as fungistatic agents. CNSL and babassu oil exhibited more significant antifungal effects at higher concentrations. Additionally, Colletotrichum gloeosporioides was generally more sensitive to treatments than Aspergillus sp., which showed greater intrinsic resistance. The results confirm that these natural compounds represent effective and eco-friendly alternatives for managing fungi in tropical fruits, reducing contamination risks and economic losses. Article 2, “Application of Biodegradable Coatings Containing CNSL and Clove and Peppermint Essential Oils for Guava Preservation,” evaluated CMC and pectin-based formulations incorporating CNSL and essential oils for post-harvest preservation of guavas during storage. The coatings significantly slowed fruit degradation, maintaining parameters such as pH, soluble solids, acidity, vitamin C content, and inhibiting microbial growth. The formulation combining clove oil and CNSL stood out for preserving visual appearance, texture, and nutritional quality, demonstrating the synergistic effect of natural compounds in post-harvest conservation. The final considerations indicate that essential oils and CNSL are promising strategies for controlling phytopathogenic fungi and preserving tropical fruits, offering sustainable alternatives to pesticides while meeting the growing demand for natural, safe, and environmentally responsible foods. The results reinforce the applicability of these bioinputs in the agroindustry and highlight the need for continued research on their mechanisms of action, formulation stability, and validation under commercial conditions, consolidating their use as an innovative and ecologically sound solution for tropical fruit preservation. Editor: Universidade Federal da Grande Dourados Tipo: Tese

2025-08-06T00:00:00Z Prado, Esmael Dias http://repositorio.ufgd.edu.br/jspui/handle/prefix/6814 2026-02-27T05:11:37Z 2024-11-04T00:00:00Z

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