Avalia??o da adsor??o de impurezas do glicerol usando res?duos de gengibre (Zingiber officinale Roscoe) como adsorvente

• Autor(a) principal: Silva, Ana Carolina da
• Data de Publicação: 2020
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: Biblioteca Digital de Teses e Dissertações da UFRRJ
• Texto Completo: https://tede.ufrrj.br/jspui/handle/jspui/6019
• topic: Isoterma de equil?brio; Cin?tica; Biodiesel; MEV; Equilibrium isotherm; Kinetics; Biodiesel; MEV; Engenharia Qu?mica

The current concern about climate change and the dependence on fossil fuel has been drawing attention for the renewable energies development. In this context, biodiesel has been considered as an alternative substitute for diesel fuel due to its environmental, economical and social advantages. However, biodiesel industry has been facing some challenges due to the high volume of glycerol produced with many impurities; because of that, it has a low economic value. Due to that, there are different techniques for glycerol purification, and the adsorption has been pointed out as a promising and efficient technology in the removal of color and impurities of glycerol. Another advantages are its low cost, easy operation and the possibility to reuse the biochars. Nowadays, there is a trend to reutilize natural products as alternative adsorbents in different adsorption processes. However, there is a lack of information about the use of these type of biomasses, specifically in glycerol purification. So, the motivation of this work was the evaluation of the adsorbent capacity of ginger residues in the removal of glycerol impurities. The adsorption was initially done using the adsorbent with thermal treatment. Using the best operational conditions, the adsorbent capacity was compared with the residues after the chemical treatment, and with the commercial adsorbents as clay and commercial activated carbon. The batch adsorption studies were carried out in order to evaluate the effect of contact time (0 to 10 min for 30 mg/L and 0-150 s for 60 and 90 mg/L), adsorbent mass (0.05 g), temperature (25, 35 and 45 ?C), and initial glycerol concentration (30, 60 and 90 mg/L). In order to obtain the rate and the equilibrium data, the experiments were conducted in a 125 mL erlenmeyer flask with 25 mL of glycerin solution of various concentrations ranging from 30 to 90 mg/L, under agitation of 180 rpm. The equilibrium was quickly reached suggesting that the speed of the adsorption was controlled by physisorption. The kinetic modelling showed that the pseudo-first order, pseudo second order and Elovich models well represented the process, indicating that the controlling steps could be described by physisorption and chemisorption simultaneously. The Freundlich isotherm best fitted the equilibrium data, implying that the adsorption was heterogeneous with multi-layers. The results of the thermodynamic study indicated that the system was endothermic, non-spontaneous, and happened with an increase in the randomness at the interface adsorbent/adsorbate. The thermal treated ginger residues showed a great adsorbent capacity similar to clay and superior to commercial activated carbon and ginger after chemical treatment.