Desenvolvimento de carvão impregnado com nanopartículas de óxidos de cobre por método verde para remoção de nitrato em águas contaminadas
| Ano de defesa: | 2016 |
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| Autor(a) principal: | |
| Orientador(a): | |
| Banca de defesa: | |
| Tipo de documento: | Dissertação |
| Tipo de acesso: | Acesso aberto |
| Idioma: | por |
| Instituição de defesa: |
Universidade Estadual de Maringá
Brasil Departamento de Engenharia Química Programa de Pós-Graduação em Engenharia Química UEM Maringá, PR Centro de Tecnologia |
| Programa de Pós-Graduação: |
Não Informado pela instituição
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| Departamento: |
Não Informado pela instituição
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| País: |
Não Informado pela instituição
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| Palavras-chave em Português: | |
| Link de acesso: | http://repositorio.uem.br:8080/jspui/handle/1/3728 |
Resumo: | Contamination by nitrate in surface and groundwater has become a growing problem worldwide. Several methods of drinking water denitrification are studied, such as electrodialysis, membrane filtration and biological treatment; however, adsorption is the most viable method for the treatment of this pollutant. Whereas the use of adsorbent materials without prior treatment is generally ineffective for the adsorption of nitrate ion, this study aimed to develop a non-polluting process of synthesis and impregnation of copper compounds nanoparticles on activated carbon, called green synthesis, with the purpose of improving the performance of coal as adsorbent for nitrate removal. It was used pomegranate leaf extract (Punica granatum) as reducing and stabilizing agent for the green synthesis of nanoparticles. The impregnated carbons with copper oxide nanoparticles were characterized using scanning electron microscopy (SEM) and transmission (TEM) techniques, energy dispersive x-ray (EDX) spectroscopy, x-ray diffraction (XRD), specific surface area (BET) analysis, micropore area (t method), micropore volume and diameter (HK method), mesopore volume (BJH method), point of zero charge (PZC) determination, and copper quantification by TXRF technique. From x-ray diffraction, Scherrers equation was used to estimate the nanoparticles diameter. After the characterization, the prepared coals were evaluated in water nitrate removal. Studies of kinetics, isotherms and thermodynamics of adsorption processes were realized. The characterization analysis showed that the synthesis and impregnation of copper oxide nanoparticles using the green method was efficient, since peaks related to the oxides were detected by XRD and according to the Scherrer?s equation, these peaks are related to the nanoparticles, because the particles estimated diameter is located in the range of few nanometers, suggesting that the natural reducing and stabilizing agent used was effective in the green synthesis. The impregnated carbons showed a decrease in surface area, pores volume and area compared to pure activated carbon, because the deposition of nanoparticles has partially blocked the pores. EDX spectrum detected the element copper only in impregnated coal samples. The impregnation of copper oxide increased the efficiency of nitrate removal by pure activated carbon by more than 400%. The experimental data were best represented by Langmuir isotherm model and the thermodynamic analysis showed that the nitrate adsorption reaction is exothermic in coal impregnated with copper oxide and endothermic in pure coal. Among the evaluated coals, charcoal impregnated with 1,5%Cu-12h at 25°C showed the best results for nitrate removal, over 40% removal and the maximum adsorption capacity, 6,4 mg g-1, which is very profitable for water treatment, because of its shortest impregnation time and its low temperature reaction (room temperature). Thus, the carbon impregnated with copper oxide nanoparticles presents a promising alternative to conventional methods of nitrate removal, since it is a simple material to be produced and eco-friendly |