Adsorção de leuco verde malaquita em biocarvão sintetizado a partir de coroas de abacaxi

• Ano de defesa: 2020
• Autor(a) principal: Santos, Cynthia Pereira dos
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal do Espírito Santo; BR; Mestrado em Agroquímica; Centro de Ciências Exatas, Naturais e da Saúde; UFES; Programa de Pós-Graduação em Agroquímica
• Palavras-chave em Português: Sorção; Biocarvão; Coroa de abacaxi; Leuco verde malaquita; Verde malaquita; Sorption; Biochar; Pineapple crown; Leucomalachite green; Malachite green; Agronomia
• Link de acesso: http://repositorio.ufes.br/handle/10/15087

Lignocellulosic biomass from agroindustrial waste have been used as a precursor in the synthesis of biochar. The biochar can be applied as an adsorbent material for the adsorption process, making this process more viable and inexpensive than the process with the activated carbon adsorbent. In this study, the biochar synthesized from pineapple crowns, which are considered rejects, was used as an adsorbent material in the adsorption of leucomalachite green in aqueous media. This dye is an organic compound resulting from the reduction of malachite green dye in alkaline solutions, which has toxic, carcinogenic and even mutagenic effects. The biomass (in natura)was characterized with thermogravimetric analysis techniques (TGA/DTG), scanning electron microscopy coupled with X-ray dispersive energy spectroscopy (SEM/EDX), % ash determination, humidity, and soluble and insoluble lignin content. The biochar, was characterized by the determination of zero-point charge (pHzpc), TGA/DTG, X-ray diffraction (XRD) and SEM/EDSanalyses. The results showed the physical and chemical properties of the material, as well as the surface characteristics and the compounds present in the biomass in natura and in the biochar. In the study of adsorption of leucomalachite green, performed in a batch test, was determined that the Sips isotherm model best fitted the adsorption equilibrium, since it presented the highest value of the determination coefficient (R2= 0.957), with maximum adsorption capacity of 4.509 mg g-1 . The equilibrium was reached in 90 minutes following the kinetic model of pseudosecond order. The activation energy of the process was determined by means of the Arrhenius equation (34.15 kJ mol-1 ). The thermodynamic study of the process showed that the adsorption was endothermic and spontaneous