Adsorção de sulfato por compósito de hidróxido duplo lamelar do tipo Mg6Al2(CO3)(OH)16.4H2O e quitosana
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Data
2022-08-18
Autores
Pessanha, Maria Luiza Gomes Soares
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Universidade Federal do Espírito Santo
Resumo
The sulfate is a common ion present in several wastewater industrial segments and domestic wastewater. The high concentration of sulfate ion could cause several types of damage, like laxative effect on humans and animals, and is related to incrustation and corrosion of industrial pipes. For the treatment of these effluents, the adsorption technique stands out for the variety of adsorbents. In this work, the SO4 2- adsorption process by the LDH-Mg-Al-CO3 and chitosan composite was carried out. The chitosan was synthesized from shrimp residues from the region, and the composite was synthesized by the co-precipitation method, common in the LDH synthesis. The DD% was determinated for chitosan, obtaining the value of 54,47% which confirms that the material obtained from the deacetylation of chitin can be considered chitosan. The characterization of adsorbents was carried out through the XDR, SEM-EDS and FTIR techniques, showing that the material has characteristic peaks and morphological aspects of LDH-Mg-Al-CO3 and chitosan before and after adsorption, indicating there was no change in the structure of the material. The kinetic test showed the SO4 2- loading by the LDH-Mg-Al-CO3 and chitosan composite was 234,15 mg g-1, and the equilibrium time was reached in 180 minutes. Applying kinetic models to the data, pseudo-first order (R² = 0,93) and pseudo-second order (R² = 0,91) resulted in similar values, and it was not possible to conclude which of them best fitted the kinetic data. With the isotherm study, it was observed the Redlich-Peterson model (R²= 0,96, β=0,84) was the best model adjusted to data, assuming behavior of the Langmuir isotherm with monolayer adsorption, because the β parameter is closer to 1. In view of the results obtained throughout the study, it was possible to observe that there was a synergy between LDH-Mg-Al-CO3 and chitosan in the composite, which resulted in better loading results of SO4 2- adsorption, in relation to the precursor adsorbents.
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Resíduos pesqueiros , Compósito , Adsorção