Adsorção e dessorção de fósforo em solução aquosa, em cerâmica vermelha sem e com pré-ativação química e termoquímica
Phosphorus, although nutrient for various organisms, is harmful to the aquatic environment when in high concentrations. In this work, the adsorption and desorption of this pollutant in aqueous solution in red ceramic, without and with chemical preactivation (dolomitic lime) and thermochemical (prior...
| Autor principal: | Cabral, Lucas Lacerda |
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| Formato: | Trabalho de Conclusão de Curso (Graduação) |
| Idioma: | Português |
| Publicado em: |
Universidade Tecnológica Federal do Paraná
2020
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| Assuntos: | |
| Acesso em linha: |
http://repositorio.utfpr.edu.br/jspui/handle/1/9191 |
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| Resumo: |
Phosphorus, although nutrient for various organisms, is harmful to the aquatic environment when in high concentrations. In this work, the adsorption and desorption of this pollutant in aqueous solution in red ceramic, without and with chemical preactivation (dolomitic lime) and thermochemical (prior calcination) were evaluated. The red ceramic, popularly known as brick, was used as an adsorbent because it is an environmental liability of construction wastes. The adsorbent materials were characterized physicochemical and texturally through pH analysis at the point of zero charge (pHPZC), X-ray diffractometry (XRD), scanning electron microscopy (SEM), Xray dispersive energy spectroscopy (EDS), X-ray fluorescence spectroscopy (XRF), particle size distribution, mercury intrusion porosimetry, helium pycnometry, thermogravimetry, Blaine and Chapelle method. Kinetic, equilibrium and thermodynamic studies of adsorption and desorption were conducted for each adsorbent. Lagergren pseudo-first order and Ho-McKay pseudo-second order models were fitted to the experimental results from the kinetic assays. Langmuir, Freundlich and Sips models were fitted to the experimental results of the equilibrium assays. With the results of the thermodynamic assays at temperatures of 25, 35 and 45 °C it was possible to verify that the processes are exothermic and spontaneous by the standard Gibbs energy (ΔG°), entropy (ΔS°) and enthalpy (ΔH°) of the reactions. For all the processes it was observed that the addition of temperature increased both the maximum amount of phosphorus adsorbed and desorbed. The pseudo-first and pseudo-second order models were adjusted to the kinetic data, with R2 0.98 to the in natura ceramic (INC) and 0.99 to the ceramic with chemical activation (CCA) and thermochemical (CTCA). The equilibrium data were better adjusted to the Langmuir model to INC (R2 0.99) and Sips model to CCA (R2 0.99) and CTCA (R2 0.99). The highest efficiencies of phosphorus adsorption achieved were 53%, 85% and 76% to INC, CCA and CTCA, respectively. In the desorption experiments, the kinetics obtained the best adjustments according to the pseudo-second order model to INC (R2 0.88) and pseudo-first order for CCA (R2 0,90) and CTCA (R2 0,74). Desorption equilibrium isotherms to the adsorbents were in accordance with the Sips model (R2 0.99). Thus, it was possible to conclude that the red ceramic can be used as an alternative adsorbent in the removal of phosphorus in aqueous solution, being an option to its final disposal in industrial landfill. |
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