http://www.tede2.ufrpe.br:8080/tede2/handle/tede2/8569 2026-04-09T14:24:25Z http://www.tede2.ufrpe.br:8080/tede2/handle/tede2/9667 Título: Proposta para reutilização de corantes da indústria têxtil através da aplicação de nanomateriais em processos adsortivos por meio da celulose bacteriana Autor: SOUTO, Thaís Jeruzza Maciel Póvoas Primeiro orientador: MORAES, Alex Souza Abstract: Currently, the state of the environment has demonstrated how important/vital it is to invest in technologies that work with systems that allow the reuse or disposal of products, since technologies are aimed at greater sustainability, either by reducing the load of pollutants and effluents or reusing these environmental liabilities in a practical application, generating savings. Thus, to mitigate the environmental impacts of the production of dyes and organic pigments from the chemical processes existing within the textile industry, between its molecule and its synthesis, this work sought to investigate the structural and morphological properties of the bioadsorbent, for application in adsorptive processes in the generation of a by-product and promoting the characterization of synthetic commercial dyes. As a bioadsorbent material, bacterial cellulose was used as an alternative method of removing dyes through adsorption, functioning as an absorbent capable of separating effectively due to its purity, elasticity, and biocompatibility. To analyze the adsorption parameters made by bacterial cellulose, the study methodology used was the UV/Vis analysis, ICP-OES, Principal Component Analysis (PCA) and Thermogravimetric Analysis (TGA). Thus, it was analyzed how much the use of recyclable technologies can promote a new way of using dyes, since nanofiltration can be contemplated by the membrane separation technique, which implies the promotion of sustainability. As results obtained, it was observed that the textile dyes, through the adsorption kinetics, presented a removal rate for C8 of approximately 16%, for C10. Adsorption kinetics can be well expressed by the pseudo-second order model, indicating the importance of chemical adsorption in the process. When carrying out the Thermogravimetric Analysis, it was noticed that the bacterial cellulose begins to lose its structural stability at 360ºC, reaching the apex at 555ºC, disappearing from the experiment, forming a subdye for reuse in a new dyeing process. In this way, it was concluded that with the amount of metals identified in the chemical composition of the dye, it is pointed out how important the use of bacterial cellulose was, also, in the promotion of disposal, since the metal develops resistance to the environment, and likewise would be a source of inorganic pollutant with high mobility and high toxicity. After analyzing the data, the result is the importance of Bacterial Cellulose (BC) in the removal of dyes in textile industrial effluents, as it degrades at a certain temperature and the dye becomes purified to be reused, thus protecting the environment and human health. Instituição: Universidade Federal Rural de Pernambuco Tipo do documento: Tese 2022-12-16T00:00:00Z http://www.tede2.ufrpe.br:8080/tede2/handle/tede2/8570 Título: Estudo eletroquímico e eletroanalítico dos biomarcadores de doenças humanas 7-metil-guanosina, orto tirosina e 3-nitro-tirosina Autor: NASCIMENTO, Raphael Fonseca do Primeiro orientador: OLIVEIRA, Severino Carlos Bezerra de Abstract: Oxidative damage in biological molecules, such as double-stranded DNA (dsDNA) and proteins are associated with numerous pathologies in the human body, such as cancer. Thus, it is of great relevance to investigate the redox mechanisms that occur in vivo for different biological processes. The present study aims to investigate the redox behavior of the biomarkers of human diseases, 7-methyl-guanosine (7-mGuo), ortho-tyrosina (o-Tyr) and 3-nitro-tyrosine (3-NO2-Tyr) on glassy carbon electrode (GCE) using voltammetric techniques, such as cyclic voltammetry (CV), square wave voltammetry (SWV), differential pulse voltammetry (DPV), and electrochemical impedance spectroscopy (EIS). The electrochemical results of o-Tyr and 3-NO2-Tyr were also compared with the para-tyrosine (p-Tyr). Electroanalytical methodologies for the detection and quantification of these species were also investigated and developed in the absence and presence of possible interferences. Oxidation of the 7-mGuo on GCE occurs in single step pH-dependent irreversible pathway with the transfer of one electron and one proton with formation of polymer products absorbing on the electrode surface. An oxidation mechanism of 7-mGuo has been proposed. An electroanalytical method for quantification of 7-mGuo at physiological pH, using GCE and DPV was proposed, with a detection limit of 3.26 μmol L-1 and limit of quantification of 10,88 μmol L-1. Electrochemical detection of 7-mGuo was also investigated in the presence of potential interference of guanine, guanosine and 7-methylguanine (7-mGua). The study showed that the anodic peak of 7-mGuo suffered no interference of these species, since oxidation occurs in a very different potential. In general, the p- and o-Tyr undergo oxidation in a single irreversible step pH-dependent, with the transfer of one electron and one proton, from the phenolic group to formation of Tyr phenoxy radical (Tyr●). However, while the p-Tyr● radical preferably polymerizes, forming a resistive film on the GCE surface, the o-Tyr● reacts preferentially with water with formation of o- and p-quinone derivatives, that are adsorbed and reversibly reduced on the GCE surface. In relation the 3-NO2-Tyr its oxidation occurs, in general, in two irreversible steps. The first step is pH-dependent, while the second is pH-independent, indicating the absence of protons in the process. The first process correspond to the oxidation of the phenolic group to form 3-NO2-Tyr●, which reacts in different ways, polymerizing, forming a resistive film on the GCE surface and/or being directly electro-oxidized to a cationic product (second step). The voltammetric data also showed that the 3-NO2-Tyr phenol group is more difficult to oxidize when compared to p- and o-Tyr molecules. Moreover, unlike p-Tyr and o-Tyr that present no cathodic peak, 3-NO2-Tyr suffers in acid medium electro-reduction in a single irreversible step with formation of two electroactive products. Such processes were assigned to the reduction of the nitro group to form hydroxylamine and amine. Thus, is clearly demonstrated that the nitro group attached, as well as the phenolic group position at the Tyr molecule, strongly influence its redox properties. The redox mechanism of o-Tyr and 3-NO2-Tyr are presented and discussed. A voltammetric method for detection and quantification of 3-NO2-Tyr in physiological medium using DPV was also proposed and a concentration range of 20 to 200 μmol L-1, presented a correlation coefficient of 0.998 and a detection limit of 6, 21 μmol L-1. The knowledge of redox mechanisms of the biomarkers of human diseases, 7-mGuo, o-Tyr and 3-NO2-Tyr, as well as the proposed electroanalytical methods for their quantification correlates and are important in the literature, as basic knowledge to future interpretation and applications in molecular biochemistry. Instituição: Universidade Federal Rural de Pernambuco Tipo do documento: Tese 2019-12-20T00:00:00Z