Transport of Cr(VI), Zn(II), and Cd(II) Ions Across Polymer Inclusion Membranes with Tridecyl(pyridine) Oxide and Tri-n-Octylamine

ABSTRACT

An experimental investigation of chromium(VI), zinc(II), and cadmium(II) ions removal from acidic chloride aqueous solutions by transport through polymer inclusion membrane (PIM) with basic ion carriers [i.e., 4-(l′-n-tridecyl)pyridine N-oxide (TDPNO) and tri-n-octylamine (TOA)] is presented. The initial fluxes of all metal ions are higher for the less basic carrier (i.e., TDPNO). On the other hand, the more basic carrier (i.e., TOA) gives higher Cr(VI)/Cd(II) and Cr(VI)/Zn(II) selectivity coefficients. In long-term chromium(VI) transport experiments, the aqueous source and receiving phase were renewed every day, whereas the PIM remained the same as in the first run: the small decrease of permeability coefficient was observed, which can be explained by the partitioning of the carrier between the membrane and the aqueous solutions. A long-term experiment was conducted out to demonstrate the durability of PIMs. The application of PIM transport process for 99% removal of chromium(VI) from galvanic wastewaters is also shown.

Key Words::

• Polymer inclusion membrane
• Removal
• Toxic metal ions
• 4-(1′-n-tridecyl)pyridine N-oxide
• Tri-n-octylamine
• Chromium(VI)
• Zinc(II)
• Cadmium(II)