Extraction of Phenol, o-Chlorophenol, o-Nitrophenol from Water by Using Liquid-Solid Extraction System Based on Tween 80-Sodium Citrate-H2O

The proper extraction conditions for phenol, o-chlorophenol and o-nitrophenol were investigated by using the liquid-solid extraction system composed of Tween 80-sodium citrate-H₂O. 10.5% (v/v) Tween 80, 2.6000 g·l^-1 sodium citrate, extraction acidity of pH 5.95 had been found optimal for extraction of phenolic compounds. Under the above-mentioned conditions the once average recoveries of phenol, o-chlorophenol and o-nitrophenol in analogous water samples were 99.5%, 95.3%, 94.7%, respectively. When sodium citrate was as salt separate phase, the acidity of the solution not only could change the shape of sodium citrate, but also had effects on extraction yield (E%) of phenols as well. Through the discussion of the extraction mechanism for Tween 80 solid phase, it was indicated that the extraction in this system had been achieved by the formation of the hydrogen bond between Tween 80 and the phenolic compounds.