Remoção do corante reativo azul 5G a partir de soluções aquosas utilizando o bagaço do maracujá amarelo como adsorvente

• Autor(a) principal: Menezes, Maraísa Lopes de
• Data de Publicação: 2010
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: Repositório Institucional da Universidade Estadual de Maringá (RI-UEM)
• Texto Completo: http://repositorio.uem.br:8080/jspui/handle/1/3818
• topic: Bagaço do maracujá amarelo (Passiflora edulis fflavicarpa); Remoção de corante têxtil; Engenharias; Engenharia Química

The textile sector requires the use of great amounts of water in its industrial processes. Its effluent contains a high level of oxidable matter, because of the use of different dyes, which might cause significant pH variations. The presence of dyes in river streams, even at small concentrations, causes changes at the biological cycles of these means. The development of appropriate technologies for treating these effluents has been a very common object of study in the last decades. Many studies have been carried out for the use of non-conventional adsorbents which have adsorptive characteristics comparable to activated coal for the removal of various kinds of dyes, such as solid agricultural residues. The yellow passion fruit, Passiflora edulis f. flavicarpa, originally from Brazil, is very commonly used in juice industry which residue is generally used for animal feeding. Thus, this study aimed at assessing the application of yellow passion fruit bagasse as an adsorbent for the removal of reactive blue dye 5G from aqueous solutions. To prepare the adsorbent it was realized the bagasse drying then to study its best condition. Firstly, the initial bagasse moisture was determined, at about 90.44%, obtained in stove for 24 hours at 105 ºC ± 3 ºC. It was also collected the mass values in function of time, by using a convective drier, operated at four different temperatures (35, 45, 55 and 65 º C) and air flux speeds at 0.8, 1.0 and 1.3 m/s. By means of the drying curves and the drying rate, it could be observed that the temperature highly influences on the bagasse drying process, once as the temperatures increase, the drying time decreases, and then the drying rate becomes higher. In order to perform this process with time and energy economy, it was verified that the best condition for drying yellow passion fruit bagasse was at 55°C and 1.3m/s of air flux speed. The drying curves and the drying rate were adequately adjusted to the models proposed by Page (1949) and Motta Lima et al. (2002) and the models proposed by Hogdes (1982) and Toffoli (2005), respectively. Other mathematical models were also adjusted for each drying process, such as: Simple Exponential, Page, Henderson and Pabis, Logarithm, two-term exponential model and Wang and Singh. The best model was chosen according to the results of the analyses of the highest R², the lowest mean error and the highest F-test. After dried, the bagasse was ground in a domestic blender and characterized by N2 adsorption measurements (specific superficial area, and average pores volume and diameter) and the size of particles determined by granulometry at a range between 0.1 and 0.5 mm. For trials of batch adsorption, the influence of the particle size and the dye solution pH, solution equilibrium time, at concentrations from 25 to 100 ppm under controlled shaking at 60 and 150 rpm, the adsorption isotherms at 25ºC and 40ºC and the bagasse desorption study were evaluated. The results showed that the best conditions for batch adsorption were in granulometry at 0,106 mm, pH 2, 30 minutes of equilibrium time, 60 rpm shaking, and it was observed that the temperature had no significant influence in adsorption. Furthermore, independent of the studied concentrations, the percentage of dye removing was about 90% which means that the passion fruit bagasse is a good alternative as an adsorbent. For assessing the conditions at stationary phase column, the phase was varied from 15 to 23 cm, with the use of particles of 0.5 mm average size, with feeding fluid dynamics variations from 1 to 4 mL/min and the initial concentration of aqueous solution at 35, 50 and 70 ppm at 25ºC. In this study, it was determined that the best operational conditions for the adsorption column were: fluids dynamics at 1mL/min, concentration of 35 ppm and 23 cm of phase height, in which was obtained a higher quantity of dye removal, about 24,1495 mg dye/g adsorbent.