TCC - Licenciatura em Química (Sede)
URI permanente para esta coleçãohttps://arandu.ufrpe.br/handle/123456789/472
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Item Adsorção dos íons metálicos Cu2+ e Mn2+ em sistema bicomponente utilizando carvão ativado preparado a partir de sabugo de milho como adsorvente(2022-05-20) Campos, Natália Ferreira; Moraes, Alex Souza; Duarte, Marta Maria Menezes Bezerra; http://lattes.cnpq.br/2069994676017059; http://lattes.cnpq.br/0440163845324480; http://lattes.cnpq.br/7441229690485153Heavy metals are used in several areas, especially in the pulp and paper industry, since their effluents contain high levels of copper and manganese, which can cause harmful effects on living systems due to their toxic nature, non-biodegradable and accumulate in organisms. This problem has led several research groups to seek treatment alternatives. Adsorption using activated carbon prepared from agro-industrial residues has been presented as an alternative for the treatment of effluents containing heavy metals. In view of the above, this work proposes the use of activated carbon prepared from corn cob as an adsorbent for the removal of Cu2+ and Mn2+ metallic ions in mono and bicomponent systems. Corn cob activated carbon was chemically activated with H3PO4. The characterization of corn cob and activated carbon was carried out by Fourier transform infrared spectroscopy, Boehm titration and determination of the pH of the zero charge point. The influence of the initial pH of the solution on the adsorptive process was studied in order to determine the pH used in further studies. Based on the results obtained, kinetic and adsorption equilibrium studies were carried out for the mono and bicomponent systems. The characterization indicated that the activation promoted an increase of carboxylic groups on the surface of the adsorbent, reduction of the pHZCP value from 4.7 in the corn cob to 3.0 in the activated carbon, increasing the pH range of the solution in which the surface of the coal becomes negatively charged, which favored the adsorption of Cu2+ and Mn2+ ions. In the study of the effect of the initial pH of the solution in a single-component system, pH 4 and 6 showed better results for Cu2+ and Mn2+ ions, respectively, whereas in the bicomponent system it was pH 4. The model that best represented the experimental data of the kinetic evolution was the pseudo-second order for monocomponent systems and for Cu2+ in the bicomponent system, while for Mn2+ it was the pseudo-first order model. In the adsorption equilibrium, it was found that the model that best fitted the experimental data was Sips for Cu2+ and Langmuir for Mn2+ in a monocomponent system. The experimental adsorptive capacity was 0.39 mmol•g-1 for Cu2+ and 0.22 mmol•g-1 for Mn2+. Regarding the bicomponent system, the antagonistic effect of the presence of Cu2+ for the adsorption of Mn2+ was verified, and the model that best described the process was the extended Langmuir process, as it indicated the highest affinity of Cu2+ with activated carbon. The results of this work demonstrate the technical potential of activated carbon prepared from corn cob for the adsorption of Cu2+ and Mn2+ ions in mono and bicomponent systems.Item Estudo da adsorção do corante amarelo de tartrazina em hidróxido duplo lamelar contendo níquel e alumínio(2023-09-22) Silva, Camilla Ferreira da; Barros, Ivoneide de Carvalho Lopes; http://lattes.cnpq.br/5272867419216787; http://lattes.cnpq.br/9913666540185102The inadequate dumping of effluents into rivers and seas by industries from different segments has caused great environmental impact and directly influenced different aquatic ecosystems. To remove these effluents, the most commonly used process is adsorption, which consists of retaining particles on the surface of solids. In this sense, this work proposed the kinetic study and other adsorption parameters of tatrazine yellow dye in aqueous solution. For this purpose, lamellar double hydroxides (LDH) containing Ni and Al in ratios 1; 0.5 and 0.25, named as HDL-Ni0,5Al0,5, HDL-Ni0,33Al0,67 e HDL-Ni0,2Al0,8 espectively, intercalated with the terephthalate anion, which were prepared via coprecipitation at pH controlled. HDL is a hydrotalcite-type compound with the general formula [M2+(1-x) M3+X (OH)-2]x+ A-x/n m.H2O .XRD results confirmed the formation of HDLs through (003) and (110) reflections, and the FTIR spectra showed characteristic hydroxyl bands between 3200-3600 cm-1, as well as absorption at 1600cm-1, and 800- 860 cm-1 related to the terephthalate anion. Furthermore, the Point of zero charge (PZC) was determined using the 11-point method, obtaining values of 5.51, 5.31 and 6.67 for HDL-Ni0,5Al0,5, HDL-Ni0,33Al0,67 e HDL-Ni0,2Al0,8. In analyzing the influence of the initial pH, the three HDLs produced demonstrated greater efficiency at an acidic pH equal to 2. Adsorption tests involving contact time demonstrated that HDLNi0,5Al0,5 and HDL-Ni0,33Al0,67 reached maximum dye removal, reaching values above 90% in solutions of 40 and 80 mg/L of contaminant, and above 30% for 160mg/L. with contact time starting at 120 minutes for concentrations of 40,80 and 160 mg/L. While HDL-Ni0,2Al0,8 the contact time was from 240 minutes, obtaining removal above 50% for the respective concentrations. Evaluating the influence of temperature, it was observed that increasing the temperature from ~29oC to 50oC promoted an increase in the removal of the dye in the solution, with all adsorbents being indicative of an endothermic process. Finally, in the kinetic study, the model that best fit the experimental data was the pseudo-second order model, indicating that the process of adsorption of the tartrazine yellow dye in an aqueous is controlled by chemisorption.Item Estudos de pré-concentração de platina explorando materiais de sílica organofuncionalizados(2022-10-13) Sousa, Filipe Carvalho Pires de; Belian, Mônica Freire; Lavorante, André Fernando; http://lattes.cnpq.br/1011018535020717; http://lattes.cnpq.br/2626644337183959; http://lattes.cnpq.br/8810636055275824The present work aims to develop an organofunctionalized material through a silylation reaction, by a heterogeneous route, using the Stöber method, capable of effectively coordinating platinum íons (Pt4+). The synthesis of modified silica was carried out by the sol-gel process, where functionalization was carried out one pot through the addition of N´-[(trimethoxysilyl)propylethylenetriamine, tetraethylorthosilicate (TEOS) and ammonium hydroxide, the latter being a catalyst for hydrolysis and condensation reactions. The adsorptive/coordinative capacity of the organofunctionalized silica was evaluated through Fourier transform infrared (FTIR) and electronic absorption techniques. Through infrared spectroscopy, it was possible to observe the presence of bands referring to silanol groups (Si-OH) between 3470 and 3090 cm- 1, and an intense broad band related to siloxane groups (Si-O-Si) at 1029 cm-1. In addition, it was possible to identify bands at 2904 and 2829 cm-1 referring to the N-H groups of the amines present in the organofunctionalization of silica, coming from N´-[(trimethoxysilyl)propylethylenetriamide, as expected; and, at 1465 cm-1, the C-N band of amines is observed. Fourier transform Infrared spectroscopy (FITR) was used as a proposal to observe, through the spectra, the possible changes that occurred with the organofunctionalized compound after reacting with a 10-4 mol L-1 potassium hexachloroplatinate solution. It was possible to observe the shift to lower wave numbers of the signals referring to the N-H and C-N bands, suggesting that the interaction between Pt4+ ions and the silica material is predominantly through coordinative bonds between the ion and the amino groups. After the studies in the infrared region, test were performed on the electronic absorption of platinum ions with different concentrations, and then an analytical curve was constructed. However, two analytical curves were performed in order to quantitatively analyze the adsorption of platinum ions on silica materials. The first with concentrations of 10-3, 10-4, 10-5, 10-6 mol L-1 resulted in a good linear regression coefficient of 0,9995. At lower concentrations, at values of 12,2, 48,8, 97,5, and 195 ppm, the linear regression was also satisfactory, but with a value of 0,9801. Thus, the synthesized compound SIL-TMSDT proved to be effective for platinum (Pt4+) adsorption and efficiency pre-concentration.Item Síntese eletroquímica da estrutura metal-orgânica de [Cu3(BTC)2 .(H2O)3]n e sua aplicação em biossensores e meio ambiente(2018-08-27) Silva, Renata Pereira da; Freitas, Kátia Cristina Silva de; http://lattes.cnpq.br/9622769576689246; http://lattes.cnpq.br/9318114882701456The MOFs (Metal-Organic Frameworks) are a new class of materials known as porous coordination networks, form an extensive class of crystalline materials, featuring a central atom (metal ion) or sintered (metallic cluster) coordinated the organic molecules (ligands), in which this unit metal-ligand repeats itself forming a polymer metal complex network in one, two or three dimensions. One of the most important properties of this metal-organic framework is the high porosity and large surface area, properties that are exploited for the development of a textile dye adsorbent material in effluent and as crippling to the Lectin of Cratylia Mollis, a specific enzyme for glucose. The MOF [Cu3 (BTC) 2 ( H2O) 3] n was obtained by electrochemical synthesis and by current limiter using an acid solution 1, 3, 5-benzenotricarboxilico, sodium nitrate and dimethylformamide in water Mllipore a ratio of 1:1. The precipitate was filtered, washed and dried in an oven at 120° C, and then was characterized by absorption spectroscopy in the infrared region using a Fourier transform with spectrophotometer (FTIR) and by cyclic voltammetry. After this MOF mix with a solution that simulated a textile effluent, it was found that it can be used in your treatment as it was retrieved from a colorless effluent and the stabilization of the dye in your structure. The developed biosensors have been drawn up with the MOF with the lectin, and graphite paste in Platinum and gold electrodes. The cyclic voltammetry of these systems in solution of glucose and fructose. Indicating that the lectin interacts with low-concentration glucose solutions with the gold record (10:15, 5 mM due to the increase of the cathode and Anodic peaks), while that with the Platinum card she interacts with high concentrations of glucose (20, 40 and 60 mM due to the increase of cathode and Anodic peaks). Interaction not observed of the lectin with fructose, as expected. This system can be used for the identification of glucans in effluents, and identification of glucose in real samples, not requiring a large amount of sample for identification, making the low-cost and efficient method.