Industrial wastewaters including those from peterochemicals petroleum refining and coking plants contain appreciable amount of phenol or chlorophenols which have been identified as a hazardous compounds for many aquatic organisms by Enviroment Protection Agencies. These Agencies stipulated for wastewater discharge is not more than 1 ppm and for drinking water has set the maximum allowable limit of 0.01 ppm. Compliance with these stringent discharge limits and the most economic was of achieveing this without loss of production has thus become a challenge to human ingenuity and responsibility. This has led to continued reflnment of existing treatment technologies and recognition and development of promosing emergent technologies like liquid-liquid extraction. In this work the efficiency of some solvents as a selective solvent in the extraction of phenol and p-chlorophenol from water was investigated. This thesis consists of three chapters. The first one is the introduction which contains theoratical background of liquid-liquid extraction and distilalition, requirements of solvent used for extraction, general physical properties of the solvents and literature survey related with these solvents. The experimental part is presented in the second chapter including purification of solvents and chemicals used for this study. This chapter also includes the experimental techniques and the experiments used for the estimation of binodal curves and tie-line compositions of two equilibrium phases. The third chapter contains results and discussion which includes the determination the ternary equilibrium diagrams and the mutual solubiilities of the binodal curves. These data are estimated for ten systems containing, phenol + water or p-chlorophenol + water as a common component liquid and -f- five solvents fethylene glycol, diethylene glycol, poly(ethylene glycol) (200),
dimethylsulfoxide and tetramethylene sulfolone (sulfolane)J. The same chapter containes the tie-line data of two equilibrium phases solvent- rich phase and water rich phase. The capacity (distribution coefficient) of The phenol in solvent and in water rich layer and selectivity of the solvent in each of the systems were determined from the tie-line data. The Plait Point for each ternary system was estimated. The consistency and accuracy of the tie line data were evaluated using three correlation relations namely, achman, Hand, and Qthmer and Tobias correlation. The distribution coefficient of phenol or p-chlorophenol in solvent- and in water-rich phase and the selectivity of solvents toward phenol or p-chlorophenol were calculated and found to be decreased in the following sequence diethylene glycol > poly(ethylene glycol) (200) > sulfolane > dimethylsulfoixide > ethylene glycol, sulfolane > diethylene glycol > poly(ethylene glycol) (200) > dimethylsulfoxide > athylene glycol, diethylene glycol > sulfolane > dimethylsulfoxide > poly(ethylene glycol) (200) > ethylene glycol and sulfolane > diethylene glycol > poly(ethylene glycol) (200) > dimethylsulfoxide > ethylene glycol respectively. The liquid-liquid equilibrium data have been predicated using non-random-two-liquid (NRTL) model and universal-quasi-chemical (UNIQUAC) model, the parameter of which was obtained from the infinite dilution activity coefficient values. MRTL and UNIQUAC models predict the calculated ternary composition at solvent-rich phase and water-rich phase. Results obtaine d from NRTL model are in good igreement with experimental data with root mean square deviation (RMSD) < 1, -vhile that obtained from UNIQUAC are not satisfy (RMSD >1). Thus the studied :ernary system is fit NRTL model. ,