Efficient chromium(VI) removal using trioctylmethylammonium salicylate as the carrier in polymer inclusion membranes.

In this study, the ionic liquid (IL) trioctylmethylammonium salicylate (TOMAS) was prepared and incorporated into a polymer inclusion membrane (PIM) based on cellulose triacetate (CTA) as the polymer for the removal of Cr(VI). Various parameters including the effect of membrane composition (plasticizer and carrier concentration) as well as variables affecting both the feed phase and receiving solution have been investigated. Optimal results were achieved with a PIM made of 50% CTA and 50% TOMAS (% in mass) without the addition of any plasticizer. Using this PIM, Cr(VI) was effectively transported from a feed solution consisting of 10 mg L-1 Cr(VI) in 0.01 mol L-1 NaNO3 at pH = 2, to a receiving solution containing 0.1 mol L-1 NaOH. The transport of Cr(VI) was not affected by the presence of other metals, such as Cr(III), Cd(II), Zn(II), Cu(II), and Ni(II), and a selective recovery rate of 93.61% for both single-ion and mixed-ion solutions after 24 h of processing was obtained. Finally, the stability of the membrane was also investigated, with a slight decrease in efficiency observed after 5 days of reuse.