APPLICATION OF A FLUORINATED SOLVENT TO THE CONVENTIONAL OZONATION PROCESS FOR THE DESTRUCTION OF 2,4-DICHLOROPHENOL

Abstract

The removal of 2,4-dichlorophenol from aqueous solution with fluorinated solvent, with ozone, and with fluorinated solvent/ozone combined was investigated. The fluorinated solvent/ozone combined system consists of a chemical extraction from the aqueous phase accompanied by oxidation with ozone in both the solvent and aqueous phase. The results of extraction tests showed that the distribution coefficient decreased with increasing initial pH value of the aqueous phase. The apparent oxidation rate constant of the aqueous ozonation for the initial pH 5.8 was close to that measured of organic phase ozonation. The initial pH value of aqueous phase plays an important role in the fluorinated solvent/ozone combined system for affecting the removal efficiency. The experiment results indicated that 2,4-dichlorophenol was removed at a faster rate at low initial pH value. Although the accumulation of 2,4-dichlorophenol in the organic phase in the fluorinated solvent/ozone combined system was observed under the condition of initial pH 10.0, the overall removal of 2,4-dichlorophenol under the condition of initial pH of 10.0 was close to the condition of initial pH 7.0. Moreover, a comparison test showed that the removal efficiency of 2,4-dichlorophenol by fluorinated solvent/ozone combined system is higher than that by homogeneous phase ozonation or extraction.