Cloud point extraction (CPE) has been applied successfully to remove the 9 compounds of polycyclic aromatic hydrocarbons (PAHs) by using nonionic surfactant Tergitol 15-S-7 as separating agent. Possibly, the CPE method may be applied in treating wastewater containing PAHs pollutants. In Addition, in order to make the process more economical and efficient, the surfactant in the surfactant rich phase should be recycled and reused.
Solvent extraction and adsorption using activated carbon were used to separate the surfactant rich phase into surfactant and PAHs. In our work, alcohols like 1-hexanol, 1-octanol, 1-decanol, and 1-dodecanol were used as a solvent to extract PAHs in surfactant rich phase and recycle the fresher surfactants. Besides alcohols, solvent like ethyl acetate also being used. Activated charcoal with 100-400 mesh and 4-8 mesh sizes were used to separate the nine PAHs and nonionic surfactant from the surfactant rich phase.
The results show that alcohols can be used to extract PAHs from the surfactant rich phase well. It is indicated from almost no PAHs detected in the lower phase after solvent extraction. And for surfactant, only about 22% of surfactant can be recovered from the surfactant rich phase after the solvent extraction process. Besides solvent extraction, adsorption using activated carbon for recovering the surfactant also can be done to separate the nine PAHs from surfactant rich phase and recover the fresher surfactant. By using this method, the surfactant recovery is above 90%.

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