Transport of chromium(VI) through a Cyanex 923-xylene flat-sheet supportedliquid membrane

The present investigation deals with carrier-facilitated membrane transport of chromium (VI) from chloride media across a flat-sheet supported liquid membrane (FSSLM) using as organic reagent the phosphine oxide, Cyanex 923. The permeation of Cr (VI) has been studied under various experimental condi tions: stirring speed of the source phase, initial metal and carrier concen trations, organic phase diluent, HCl concentration in the source phase, com position of the stripping phase and support characteristics. The mass trans fer coefficient was calculated as 67 mu m/s and the thickness of the aqueou s boundary layer was calculated to be 15 mu m Chromium permeation and thus speciation across the membrane was also investigated, and the order found w as: CrO42- = Cr2O72- > Cr3+. (C) 2000 Elsevier Science B.V. All rights rese rved.