Extraction and pertraction of phenol through bulk liquid membranes

The extraction and pertraction of phenol through a bulk liquid membrane (BLM) with Cyanex ® 923, Amberlite ® LA‐2 and trioctylamine (TOA) as carriers were studied. Cyanex ® 923 was selected as the best carrier for pertraction. The distribution coefficient of phenol for solvents with carrier and pure n ‐alkanes, the individual mass‐transfer coefficient at the extraction interface and the initial flux of phenol through the extraction interface ( J Fo ) decreased in the order: Cyanex ® 923 > Amberlite ® LA‐2 > TOA ≫ pure n ‐alkanes. The opposite order was observed for the value of the mass‐transfer coefficient in BLM and the maximum flux of phenol through the stripping interface ( J Rmax ). At constant driving forces the maximum fluxes through the extraction and stripping interfaces were similar when amine carriers were used. However, J Rmax was lower than J Fo for Cyanex ® 923. Although the kinetics of stripping was the rate‐determining step, the flux of phenol was significantly higher than in pertraction with amine carriers. The adsorption of the carrier at aqueous phase/membrane interfaces was probably responsible for the rapid and slow transfer of phenol through the extraction and stripping interface, respectively. Copyright © 2004 Society of Chemical Industry