Phenolic compounds are pollutants with high toxicity even at low concentrations. The focus of this study is the stripping of phenol from the organic phase resulting from the extraction of phenol in aqueous solution with 1-decanol as solvent, using a membrane contactor. A simultaneous extraction-stripping process, using two membrane contactors, was carried out, yielding 99% phenol recovery and continuous regeneration of the organic phase.
Phenolic compounds are considered priority pollutants which are present in chemical, petrochemical, pharmaceutical, paint, pulp and paper industries and olive mill wastewaters. The discharge limits for phenolic compounds are 0.1 mg/L in non-chlorinated water and 0.001-0.002 mg/L in chlorinated water . Since phenol is usually present in the aforementioned wastewaters at concentrations higher than 50 ppm, they must be treated to reduce phenol concentration to strict discharge limits.
A conventional separation technique, among other methods, for phenol recovery is liquid-liquid extraction. The selection of a suitable solvent or solvent combination would enhance phenol extraction. In many cases liquid-liquid extraction enables the stripping of the phenolic compounds for further use.
One disadvantage of liquid-liquid extraction is the formation of stable emulsions, that may narrow the range of operating conditions, because of loading or flooding constraints.