(104f) Porous Membranes In Liquid Membrane Permeation

Supported liquid membrane separation is a very efficient technology [1]. Until now supported liquid membrane separation has not established in industrial scale because of membrane bleeding.

To overcome bleeding, stabilization of the membrane is subject of ongoing research activities. Improvement has been expected from feeding the solvent phase directly in PE- membranes cross currently to the mass transfer direction.

Therefore membrane carrier modules needed to be characterized considering pore size, voidage, membrane thickness, phase flow rate and bleeding. Membrane thickness was varied in a range of 1 to 5 mm, pore size was 7 to12 µm and 20 to 60 µm and porosity was 37%. The best compromise between membrane bleeding, pore size distribution and flow rate was obtained for membrane modules with a pore size distribution of 20-60 µm and 2 mm thickness.

After hydraulic characterization mass transfer was investigated with the test system Zn2+/DEHPA/H2SO4. DEHPA was dissolved in ShellSoll-T, a hydrocarbon blend. Mass transfer experiments included transfer of constituents and water transfer. In a first step mass transfer was measured without any solvent flux, in a second step the organic solvent phase was pumped through the membrane. Mass transfer showed positive dependence on flow of the organic phase perpendicular to the mass transport direction. Enhancement was limited. Extended solvent flux perpendicular to the mass transport direction did not rise mass transfer.

[1] N.M.Kocherginsky; Q.Yang; L.Seelam Recent advances in supported liquid membrane technology, Seperations and Purification Technology 2007, 53 171-177