Avaliação da seletividade de adsorção de isômeros de xileno em heteroestruturas de argila porosa e recuperação de xilol

• Autor(a) principal: Cardoso, João Victor de Sousa
• Data de Publicação: 2018
• Tipo de documento: Trabalho de conclusão de curso
• Idioma: por
• Título da fonte: Repositório Institucional da Universidade Federal do Ceará (UFC)
• Texto Completo: http://www.repositorio.ufc.br/handle/riufc/39238
• topic: Xilenos; Xilol; Seletividade; Heteroestruturas de argila porosa

The first part of this work is the study on the selectivity of adsorption of xylene isomers in porous clay heterostructures (PCH) that act as molecular sieves. The isomers of xylene (para-, meta- and ortho-xylene) and ethyl-benzene are volatile organic compounds that are isomers of one another that have an aggregate commercial value, as they are the raw material for plastics, dyes and other products. The separation of such compounds is difficult because they have very close boiling points. Three clays with Zr, Ti and Si (PCH-Zr, PCH-Ti and PCH-Si) pillars were studied, in order to determine which xylene isomer each clay is selective in its adsorption providing an alternative for the separation and purification of such isomers. Experiments were performed by adding a certain amount of an equimolar mixture of the four isomers following the adsorbate/adsorbent (g/g) mass ratios of 0.05 to 0.20 in a fixed mass of 0.05 g of adsorbent. Then, the system was heated at 40 ° C for 30 min. Then the molar fractions of the vapor phase isomers of the system were determined by means of gas chromatography with headspace sampling to determine the selectivity of the PCHs. It was found that all PCHs showed selectivity to meta-xylene. The highest values of selectivity were those of meta-xylene with respect to ethyl-benzene for all clays. For PCH-Zr, meta-xylene/ethyl-benzene selectivity of 1.64 was obtained. For PCH-Si, meta-xylene/ethyl-benzene selectivity of 4.28 was obtained. For PCH-Ti meta-xylene/ethyl-benzene selectivity of 1.78. These values show that the PCH's have potential for the separation of such isomers by adsorption. The second part is based on methods of xylol purification used in pathological analyzes by means of distillation and solvent extraction. The samples of xylene used undergo simple distillation in order to separate xylol and ethanol from paraffin and other organic and biological impurities. The distillate was then subjected to solvent extraction using deionized water. The purified product was analyzed by gas chromatography, obtaining purity values of 98.6%, this being the minimum required to guarantee purity.