Liquid–liquid extraction and transport across supported liquid membrane of phenol using tributyl phosphate

In the present work, the extraction of phenol by liquid–liquid extraction procedure and by supported liquid membrane (SLM) system using tributyl phosphate (TBP) has been explored. Firstly, the liquid–liquid extraction of phenol with mixture of TBP and hexane, 2-octanol, or kerosene was investigated. The addition of TBP improves the extraction efficiency and more than 90% of phenol was extracted after only 3 min of contact with tested mixtures. Secondly, taking into consideration the obtained results, the transport of phenol across a flat-sheet SLM (FSSLM) containing 20% (v/v) TBP in kerosene as liquid membrane phase was studied. Several operational variables such as TBP concentration, source solution pH, initial phenol concentration, stripping reagent (NaOH) concentration and polymeric support type were examined. Under optimum conditions, an initial flux value of 1.4 × 10−5 mol m−2 s−1 has been determined. Finally, the stability of the SLM system was checked. The system can be considered as stable using polyvinylidene difluoride (PVDF) as a polymeric support since only a 17% decline in the transport efficiency was observed after 3 days of continuous run.