Influence of Sub-CMC Rhamnolipid Flushing on the Mobilization and Solubilization of Residual Dodecane in Saturated Porous Media
2024
Xin Yang | Hua Zhong | Guansheng Liu | Lili Huo | Zonghua Wang
The potential of monorhamnolipid (monoRL) biosurfactant to enhance the removal of residual dodecane from a porous medium was investigated under monoRL concentration varying from sub-CMC to hyper-CMC conditions by one-dimension column experiments. In the immiscible displacement experiment, 76% of the total volume of dodecane is removed by flushing of 150 &mu:M monoRL solution. The solubilization of dodecane could be enhanced by rhamnolipid even at monorhamnolipid concentrations as low as 50 &mu:M/L. The higher solubilization concentration (500 &mu:M/L) of monoRL solution results in higher solubilized dodecane concentration (160 &mu:M/L) due to the larger quantity of micelle formation. Compared to solubilization, immiscible displacement, or mobilization, is far more effective in removing residual dodecane. The interfacial partitioning tracer tests (IPTT) method is applied to measure the variation in specific dodecane-water interface areas (Anw). The results showed that the flushing of monoRL increased the Anw from 2.04 to 3.54 cm2/cm3. This investigation implies that low-concentration monorhamnolipid flushing and subsequent micelle solubilization is an economic method to remediate NAPL-contaminated fields.
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