Selective removal of phenanthrene from SDBS or TX100 solution by sorption of resin SP850

Surfactant enhanced remediation (SER) is a promising technology for the removal of hydrophobic organic compounds (HOCs) from contaminated soils. Recycling of soil washing effluent by selective removing of HOCs from surfactant solutions, using techniques such as sorption, is a keyway to reduce the operation costs of SER. In this study, a potential and economical method to recycle washing effluent and lower operation costs of SER, i.e., selective sorption of phenanthrene from an anionic surfactant (sodium dodecylbenzene sulfonate, SDBS) or a nonionic surfactant (Triton X-100, TX100) solution by a resin, SP850, was developed. A modified selectivity parameter (S*), having a parabolic equation with a maximum S* value, was developed to evaluate the efficiency of the selective sorption process, the optimal surfactant concentration and SP850 dose for SER. For example, at the given SP850 dose of 1.0 g/L, the optimal concentrations of SDBS and TX100 for SER are about 15000 mg/L and 8000 mg/L, respectively. Moreover, the optimal added SP850 dose for recycling washing effluents is 1.5 g/L, which is independent of surfactant concentration. At the relatively high concentrations of surfactant used in SER, the selective sorption is depended on the sorption of phenanthrene by SP850 and the solubility enhancement of phenanthrene into surfactant micelles in solutions. The observed recycling soil washing effluent method by selective sorption using resins (e.g., SP850) as the adsorbents would be helpful for the application of SER in remediating contaminated soils.