Evaluation of Biosurfactants and Surfactants for Crude Oil Contaminated Sand Washing

In this work, biosurfactants (rhamnolipid, surfactin) and commercial surfactants (SDS, Triton X-100) were evaluated for their ability to recover crude oil from sand in laboratory experiments. The rhamnolipid used in this study was produced by Pseudomonas aeruginosa PTCC 1310, while the surfactin was produced by Bacillus subtilis NLIM 0110. Both biosurfactants were able to reduce surface tension to less than 27 from 72 mN/m with critical micelle concentration values of 50 and 118 mg/L for surfactin and rhamnolipid, respectively. It also demonstrated that the biosurfactants and surfactants are useful for the sand washing with removal percentages of 80%, 77%, 65%, and 61% at the room temperature for rhamnolipid, surfactin, Triton X-100, and SDS, respectively. At room temperature produced rhamnolipid removed the most oil from the sand (80%) compared to the rest of the candidates and also formed an excellent emulsification of crude oil (88%).