Síntese de compósitos MgAl/HDL-biocarvão de ouricuri para aplicação na remoção de poluentes emergentes

• Autor(a) principal: Santos, Grazielle Emanuella de Souza dos
• Data de Publicação: 2019
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: Repositório Institucional da Universidade Federal de Alagoas (UFAL)
• Texto Completo: http://www.repositorio.ufal.br/handle/riufal/4792
• topic: Hidróxido duplo lamelar; Biocarvão; Adsorção; Poluentes emergentes; Diclofenaco de sódio; Lamellar double Hydroxide; Biochar; Adsorption; Emergent pollutants; Diclofenac sodium; CNPQ::ENGENHARIAS::ENGENHARIA QUIMICA

Emerging pollutants are contaminants in which their recent prominence has been causing various concerns due to their effects on the ecosystem and human health. These contaminants encompass diverse groups of compounds and are present in several products, such as caffeine and diclofenac sodium. Studies on the use of the adsorption process to remove these types of contaminants have been well evidenced. The use of biochar supported lamellar double hydroxides (LDHs) has had promising results as adsorbents. In the present work, the biofilm of ouricuri (Syagrus coronata), produced by the MgAl/LDH synthesis, was produced by pyrolysis by the co-precipitation method and the formation of the MgAl/LDH-biochar composite was performed with the objective of analyzing the as adsorbent agents for the removal of emerging pollutants such as caffeine and diclofenac sodium. The adsorption study showed that MgAl/LDH and the MgAl/LDH-biochar composite had an affinity for sodium diclofenac adsorption, obtaining removal approximately 82%. For caffeine, none of the adsorbents was promising. The models of pseudo-first and pseudo-second order, for the kinetic study, and the Langmuir, Freundlich, Redlich-Peterson and Sips models for the adsorption isotherms were evaluated. Moreover, they showed that for adsorption kinetics, the predominant mechanism is physisorption at low concentrations. While, with increasing concentration the adsorption tends to be more complex and that the chemisorption is predominant in the process. For the isotherm, the best suited model was Sips and he predicted that the maximum adsorption capacity would be 168 mg diclofenac sodium per 1 grams of the MgAl/LDH-biochar composite that obtained better performance when compared with other adsorbents. The models were evaluated by the statistical parameters of linear correlation coefficient (R2), relative mean error (AER), Akaike information criterion (AIC) to determine the best fit. For characterization, thermogravimetric analyzes (TGA and DrTGA), nitrogen adsorption by the Brunauer, Emmett and Teller method (BET), Dispersive Energy X-Ray Fluorescence Spectroscopy (EDX), X-ray diffraction (XRPD) and Spectroscopy of Fourier Transform Infrared (FTIR), the formation of LDH containing magnesium and aluminum cations in the lamellae interspersed with chloride anion was confirmed.