Extraction of phenol from aqueous effluent using triglycerides in supported liquid membrane.

This research work focuses on the removal of phenol using a flat sheet supported liquid membrane
impregnated with triglycerides (vegetable oils). The mass transfer of phenol was found to
be dependent on various factors such as type of vegetable oil, support material, feed phase pH and
concentration, stripping phase concentration and stirring speed. The phenol transport was found
to be higher when PTFE membrane (pore size 0.45 mm) impregnated with coconut oil was used
and mass transfer coefficient was found to be 3.50 � 10�6 m/s. The corresponding stirring speed,
pH of feed solution, concentration of stripping (NaOH) solution were 350 rpm, 4.0 and 0.2 M,
respectively. The 92.5% of phenol was extracted from feed phase to stripping phase in 20 h. The
aqueous boundary layer thickness reduced with an increase in stirring speed up to a certain extent
(350 rpm), beyond which, it resulted in turbulence leading to displacement of impregnated oil
from membrane pores. Phenol can be transported through the membrane, when it is present in
molecular or undissociated state in aqueous solution. Since the pKa value of phenol is 10, the phenol
will be present in undissociated form when the pH of the feed solution was 4.0, which resulted
in the highest membrane mass transfer coefficient. The extraction of phenol was found to be
dependent on the composition of fatty acids (chain length and position of double bond) in triglyceride.
It may be concluded that PTFE membrane impregnated with triglyceride from coconut can
be successfully used for the extraction of phenol from aqueous feed.