| Summary: | 碩士 === 國立成功大學 === 化學工程學系碩博士班 === 97 === This study investigated the interfacial properties of surfactin, such as surface tension lowering activity, foaming ability and foam stability, emulsification ability, and solubilization efficiency. Surfactin was then used in solution flushing and foam-enhanced solution flushing techniques to remove n-pentadecane from packed columns to evaluate the potential of applying the biosurfactant in soil remediation. The critical micelle concentration of surfactin was about 2×10-5 M, and the surface tension of water could be lowered to 30 mN/m. The foaming ability of the surfactin solutions was enhanced with a higher surfactin concentration. However, the foam stability became lower with increasing the surfactin concentration. In addition, the stability of n-pentadecane/water emulsions was higher with a higher surfactin concentration, and the molar solubilization ratio of surfactin for n-pentadecane was found to be 0.56. The removal efficiency for n-pentadecane from a packed column was about 5% by using the solution flushing technique with a 1.5×10-4 M surfactin solution. The removal efficiency for n-pentadecane was significantly increased to about 85% with the foam-enhanced solution flushing approach probably due to the less pronounced channeling effect in the packed column. It is suggested that the solubilization effect was a less important factor in the n-pentadecane removal as compared with the mobilization effect. Furthermore, with the foam-enhanced solution flushing technique, higher removal efficiency for n-pentadecane was obtained with higher surfactin concentrations and larger gas/liquid flow rate ratios. The results also showed that surfactin has the advantage over Triton X-100 of removing n-pentadecane from the packed columns.
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