Application of L-3 sponge phase as an extractant in extraction of polycyclic aromatic hydrocarbons (PAHs) from aqueous solution were studied systematically at 25 degrees C with three nonionic surfactants, Tergitol 15-S-5, LE-203 (C12E3), and Brij 30 (C12E4). The transition temperatures of the coexisting W + L-3 phases of these surfactants could be regulated with the addition of proper salting-out electrolytes and short-chain alcohols. The low viscosities of these L-3-phase extractants, ranging from 10 to 40 mPa s, make it not difficult for separation of these extract-containing L-3 phases from the coexisting water (W) phases. Compared to the conventional cloud-point extraction techniques, a relatively larger preconcentration factor with satisfactory recovery efficiency of PAHs are achieved in such L-3-phase extraction procedure. For example, a preconcentration factor as much as ca. 200 was achieved in 0.2 wt % Tergitol 15-S-5 solution added with 5.6 wt % NaCl. In general, a higher preconcentration factor is attained with a decrease in surfactant concentration and/or with increasing concentrations of additives employed in this work. (c) 2007 American Institute of Chemical Engineers