https://ri.ufs.br/jspui/handle/riufs/8143 2026-10-30T15:09:11Z https://ri.ufs.br/jspui/handle/riufs/26176 Title: Development and implementation of theoretical methodologies for the study of luminescent systems Authors: Silva, Gustavo de Santana Abstract: Accurate prediction of excited state energies is extremely important for studies in various fields. In lanthanide complexes, calculations for determining excited states are generally performed using ab initio methods, TDDFT, or the semi-empirical INDO/S-CIS method. The first two cases are limited to systems containing a few dozen atoms. Although capable of handling large molecules, the semi-empirical quantum INDO/S-CIS method exhibits high errors when excitation window adjustment is not performed. Thus, we propose two parameterizations of CIS methods based on the INDO and NDDO approximations, named INDO/S-CIS2 and NDDO/S-CIS, for calculating the singlet and triplet excited state energies of systems containing lanthanide ions. To validate the methods, we compared the results obtained against TDDFT methodologies, based on a benchmark study, and INDO/S-CIS. Both developed methods presented errors smaller than or equivalent to those of the TDDFT methodologies. The error ranges for INDO/S-CIS2 and NDDO/SCIS were 10.43 ± 9.53 and 9.52 ± 7.13, respectively, for the singlet energy, in a set of 41 structures. For the triplet energy, in a set of 87 structures, the error ranges were 9.46 ± 6.88 and 7.68 ± 5.65, respectively. Furthermore, we also present the second version of the LUMPAC software with the incorporation of new methods and resources. Methods for calculating Judd-Ofelt intensity parameters from the excitation spectrum were implemented, as well as a methodology for calculating energy transfer rates for Tb3+ compounds. A novel module for visualizing molecular orbitals was also introduced, facilitating the characterization of excited states centered on the ligands involved in the energy transfer process and the interpretation of the theoretical absorption spectrum. The molecule viewer was optimized. The corresponding Jablonski diagram is generated automatically. In addition, code improvements have been made. 2026-07-30T00:00:00Z https://ri.ufs.br/jspui/handle/riufs/26108 Title: Avaliação de biocarvões na miniaturização da MSPD para determinação de resíduos de pesticidas em alimentos para bebês Authors: Nascimento, Roseane dos Santos Abstract: Commercially available foods based on fruits, vegetables, meat and cereals are offered to babies from the age of six months chemical such as pesticides are used in crop cultivation to boost production meeting market demand and controlling pests that hinder plant and fruit growth. Residues of these compounds can remain in the final product and potentially affect a baby’s health; consequently, analytical methods are developed to detect contaminants in various samples. The use of miniaturized methods emerged as a way to reduce solvent volume and the amounts of adsorbents, as well as to eliminate steps compared to conventional method. Thus, this study aimed to develop a miniaturized MSPD method using pipette tips to extract the pesticides abamectin, acephate, acetamiprid, azoxystrobin, bifenthrin, clothianidin, difenoconazole, dimethoate, epoxiconazole, flutriafol, imidacloprid, lufenuron, malathion, methomyl, permethrin, pyraclostrobin, teflubenzuron, thiacloprid, thiamethoxam and thiophanate – methyl from pasty baby foods, in conjunction with liquid chromatography and DAD/UV-Vis detection. Commercial adsorbents C18, sílica gel, PSA, florisil, neutral alumina and the synthetic adsorbent TEOS were tested, as were solventes including methanol, acetonitrile, and mixtures with dichloromethane and ethyl acetate, evaluated at various volumes and ratios. The optimal extraction conditions involved using 40 mg of sample (fortified at 1 µg mL 1 ), 60 mg of sílica gel and 1000 µL of MeOH:ethyl acetate (50:50 v,v), yielding recoveries between 70 – 108 %. Subsequently, the parameters of the sample preparation method using corn cob biochar the adsorbent material that proved most efficient for analyte extraction under the same conditions previously established for sílica, but employing MeOH for analyte elution recovery rates ranged from 62 % to 112 %. Finally, the two methods developed in this study were validated by evaluating the parameters of linearity, sensitivity, selectivity, limit of detection, limit of quantification, accuracy, and precision. Subsequently, the methods were applied to samples of different brands and compositions marketed in Sergipe, but the pesticides under study were not found. 2026-07-30T00:00:00Z https://ri.ufs.br/jspui/handle/riufs/26085 Title: Investigação teórica de complexos luminescentes de eu3+: elucidação dos mecanismos de transferência de energia e desenvolvimento de um protocolo computacional para predição do rendimento quântico Authors: Rodrigues, Jocelia Silva Machado Abstract: This work aimed to theoretically investigate the luminescent propertiesof Eu3+complexes containing β-diketonate ligands, focusing on understandingtheenergytransfer and backtransfer mechanisms responsible for the luminescent efficiencyofthese systems. Using semi-empirical methodologies, four complexes withpotential technological applications were studied: [Eu(tta)3(5,5’-dmbpy)] and [Eu(btfa)3(5,5’-dmbpy)], applied in the construction of OLED devices, and [Eu(tta)3(δ-val)(H2O)] and[Eu(btfa)3(δ-val)(H2O)], investigated as luminescent markers for gunshot residue.The theoretical investigation of these systems was necessary to understand, at themicroscopic scale, the photophysical processes that govern the luminescentperformance of the complexes, allowing them to be correlated withtheoptical properties observed experimentally. The theoretical results obtained agreedwell withthe experimental data provided by collaborators, demonstrating that thecalculatedproperties consistently describe the luminescent behavior of the studiedcompoundsand explain their efficiency in different technological applications. Inadditiontophotophysical studies, this thesis also involved the development of anewcomputational protocol for predicting the quantum yield in Eu 3+ complexes. Themodel was parameterized and validated using experimental quantumyield dataavailableinthe literature for a library composed of 17 Eu 3+ complexes. The results demonstratedhigh accuracy in reproducing the experimental quantum yields, presentingameanabsolute error of around 10%, a value significantly lower than those observedfortheanalytical models traditionally employed in the literature, whose mean errorsrangedbetween approximately 20% and 55%. Thus, this work contributes to theelucidationof the photophysical mechanisms of Eu 3+ complexes and presentsanewcomputational methodology for the precise prediction of quantumyield. 2026-07-27T00:00:00Z https://ri.ufs.br/jspui/handle/riufs/25394 Title: Remoção de poluentes emergentes por adsorventes desenvolvidos a partir de resíduo sólido de estação de tratamento de água Authors: Fernandes, Erica Porto Abstract: The increasing presence of pharmaceutical compounds in aquatic environments has caused significant environmental impacts. Conventional treatment methods face challenges at the industrial scale, while abundant and low-cost adsorbents, such as industrial process residues, offer a sustainable alternative for the removal of pharmaceuticals. In this study, adsorbent materials were developed from sludge generated by the water treatment system of a thermoelectric power plant. Adsorption studies were carried out using unmodified sludge (RPL), chemically modified sludge with dodecyl trimethylammonium chloride (RMQ), and thermally modified sludge (RMT). The materials were applied for the removal of ibuprofen, diclofenac, hydroxychloroquine, and losartan in aqueous medium. Different characterization techniques were performed for the adsorbents. X-ray fluorescence (XRF) revealed the presence of Si, Al, and Fe as the predominant elements. Fourier transform infrared spectroscopy (FTIR) showed vibrational bands associated with Si-O-Si, Si-O-Al, Si-O, Si-OH, and CH₂ groups, while X-ray diffraction (XRD) indicated similar patterns among the materials, with crystalline phases such as SiO₂ and NaAlSi₃O₈. The chemical modification of the residue promoted a moderate increase in surface area and led to an improvement in the removal efficiency of the pharmaceuticals, with values higher than 70.00%.The adsorption capacities obtained in batch adsorption studies were 101.43 mg g-1 for losartan, 73.77 mg g-1 for diclofenac, 24.81 mg g-1 for ibuprofen, and 39.25 mg g-1 for hydroxychloroquine. In fixedbed column adsorption studies, the adsorption capacities were 46.71, 51.70, 44.86, and 20.43 mg g-1 for hydroxychloroquine, losartan, diclofenac, and ibuprofen, respectively. Chemical regeneration of the adsorbents allowed their reuse for most pharmaceuticals, although a reduction in adsorption capacity was observed after successive cycles. The electrochemical degradation of the pharmaceuticals was evidenced by the reduction of the characteristic anodic peaks in the voltammograms, indicating a decrease in the concentration of electroactive species in solution. Ecotoxicity tests using pharmaceutical solutions resulted in EC50,48 h values of 3.81, 24.11, 175.50, and 53.92 mg L-1 for hydroxychloroquine, diclofenac, losartan, and ibuprofen, respectively. The results obtained in this study demonstrated the feasibility of using this residue due to its efficiency in removing pharmaceuticals and its potential applicability at an industrial scale. Furthermore, the reuse of this residue may contribute to reducing its environmental impacts. 2026-03-27T00:00:00Z