Recovery of phenol from aqueous solution by supported liquid membrane using vegetable oils as liquid membrane

The transport of phenol through a flat sheet supported liquid membrane (SLM) containing vegetable oil as liquid membrane (LM) has been investigated. The permeation of phenol was investigated by varying the experimental conditions like, selection of LM, support material, feed phase pH, stripping solution concentration, stirring speed and different initial concentration of phenol. It has been found that, each LM investigated in the present study shows the effective removal of phenol using polytetrafluoroethylene (PTFE) membrane and PP supported membrane as a solid support. Among the various oils tested, palm oil has chosen to be the best LM with permeability of 8.5 x 10(-6) m/s in acidic feed of pH 2.0 with 0.2 M sodium hydroxide as effective stripping agent. After 6 h all the phenol from the feed side gets transported to strip solution with an initial concentration of 100 mg/L. A concentration factor of five has been achieved in the present investigation easily with 0.2 M sodium hydroxide as striping reagent. After 10 transport studies with one impregnation of LM, the LM showed no significant loss in the transport rate with average permeability of 7.9 x 10(-6) m/s with initial concentration 100 mg/L. Further study has also been attempted with cresols to explore the possibility of applying this to industrial wastewater under the optimized conditions for phenol. After 14 h of the transport studies in the phenol-formaldehyde industry wastewater, phenolic concentration in the feed solution was found to be below detectable level (1 x 10(-2) mg/L). For wood processing industry wastewater the transport takes place at the initial permeability of 7.1 x 10(-5) m/s. Thus it has been demonstrated the use of renewable, cheap, non toxic, naturally occurring vegetable oils as a novel, green liquid membrane for the recovery of phenol from aqueous solution in SLM, which has never been employed before in liquid membrane techniques. (c) 2005 Elsevier B.V. All rights reserved.