Study On Phenol Extraction With Hollow Fiber Membrane

Phenol and its derivatives are among the most prevalent chemical pollutants in industrial wastewater. Conventional liquid-liquid extraction methods have some drawbacks relevant to the dispersion of phases like solvent carry over and contamination. These limitations can be eliminated by combining liquid-liquid extraction with membrane separation.In this paper, the abatement technology for phenol-containing wastewater has been reviewed, particularly for the membrane based solvent extraction. The extraction performances of methyl isobutyl ketone(MIBK), Diisopropyl ether(DIPE), toluene, octanol and Tri-Butyl-Phosphate(TBP) have been evaluated. The effects of pH, temperature and salt concentration on solvents’extraction abilities have been studied. Octanol has shown synergetic effect with other physical extractants. The extraction abilities of MIBK and TBP-kerosene are favorable based on the research. The acidic condition, reduction of temperature and high concentration of salt are preferable for extraction.The 20%TBP-kerosene and hydrophobic polypropylene hollow fiber membrane were used to conduct the membrane based solvent extraction experiment. The mass transfer of phenol during the extraction and stripping has been discussed, experiments were implemented to study the influence of hydrodynamics, temperature and concentration of NaOH on extraction and stripping. Then experimental values of the overall mass transfer coefficient were determined and compared with calculated values. Major resistance in extraction is in the aqueous phase and stripping phase; resistance in organic phase and membrane dominate the overall mass transfer resistance; overall transfer coefficient in extraction is one order of magnitude greater than that in stripping. Increasing the temperature and concentration of NaOH would both enhance the mass transfer efficiency; the tardiness of mass transfer in stripping would slow down the solvents’recovery.Experiment on phenol-containing wastewater has been conducted; Over 98% of phenol reduction was achieved. Phenol-containing wastewater treatment process and phenol recovery system have been discussed; there must be an oil and suspended solids removal process before phenol abatement and recovery. Economic analysis of the system has been done, the consumption of membrane and reagents accounts for the biggest costs.