Recovery Rate in the Concentration of Semivolatile Polycyclic Aromatic Hydrocarbon(PAH) Solutions

Dichloromethane, acetone, and methanol solutions containing semivolatile polycyclic aromatic hydrocarbons with 2 to 6 rings were concentrated using rotary and centrifugal evaporators, and spraying nitrogen, and their recovery rates were compared. With concentration using a rotary evaporator, the recovery rate of low-molecular-weight PAHs was found to be low, but by adjusting the pressure in accordance with the volatilization pressure of the solvent, an almost uniform recovery rate was achieved. When a centrifugal evaporator was used, the recovery rate was approximately 60 %. However, since high-molecular-weight PAHs tended to attach to the internal wall of the vessels used, washing was carried out by applying ultrasonic waves, which improved the recovery rate. With concentration based on nitrogen spraying, an almost uniform recovery rate was achieved.