Several new three-liquid-phase extraction systems containing ethylene oxide-propylene oxide (EOPO) random copolymers have been developed. These systems were used for treating simulated wastewater containing phenol and p-nitrophenol (p-NP). Effects of pH, phase-forming components and their concentrations on partition behaviors of phenolic compounds were investigated. Results showed that phenol and p-NP could be unevenly and efficiently partitioned among the phases at pH 9.3, with about 80% phenol in the top phase and 95% p-NP in middle phase, respectively. Separation factor of two compounds increased remarkably with the increase of pH froth 4.0 to 10.0. The three-liquid-phase system containing poly(ethylene glycol-ran-propylene glycol) and butyl acetate (BA) was proved to be suitable for phenol and p-NP separation. The separation factor was over 13 at pH 8.43. (c) 2005 Elsevier B.V. All rights reserved.