| 초록 |
Rancid compounds in waste vegetable oil is one of the most critical issue for biodiesel production. The rancid compounds consist of free fatty acid (FFA) and chlorophyll which hinder transesterification and hydrogenation. To enhance quality and yield, pretreatment of waste vegetable oil should be needed in process of the biodiesel conversion. Among various pretreatment process, adsorption method has attracted great amount of attention due to environmental and economic aspects. To correspond suitable efficiency, mesoporous silica has been considered as candidate material for the adsorption of organic or inorganic molecules. The porous structure and the surface functionality are important parameter for rancid compounds adsorption. In this study, we purposefully focused on the understanding of structural and surface properties of the mesoporous silica on the pretreatment efficiency of waste vegetable oil. Three different types of surfactants were used as the template to control the pore size of the silica, and then the amine functionality was introduced on the silica surface. The silica controlled by the pore size and the amine functionality was characterized by XRD, TEM, SEM, FT-IR, BET and MAS-NMR for investigating the structure and the surface property. Adsorption kinetics of rancid compounds on the mesoporous silica were observed, which was quantitatively analyzed by Langmuir and Poltorak model. The mesoporous silica was successfully synthesized with uniform pore size of 2.6 nm, 4.9 nm and 8.8 nm. The highest performance showed in the pore size at 4.9 nm, suggesting that interaction between the silica and the rancid compounds could be optimized in this point. The amine-functionalized mesoporous silica showed higher removal efficiency of FFA and chlorophyll than the bare silica. Based on this results, it is expected to facile pretreatment of waste vegetable oil using the functionalized mesoporous silica. |
