Non-dispersive liquid extraction of Cr(VI) by TBP/Aliquat 336 using chitosan-made hollow fiber

TBP and alkylammonium extractants were investigated for chromate removal fr om dilute solutions using chitosan-made hollow fibers. Chromate is adsorbed by the chitosan fiber and simultaneously desorbed by the extractant. The i nfluence of chromate concentration, extractant concentration, extractant vo lume on relative concentration decrease were investigated as a function of time. These experimental parameters barely influenced the decrease in the r elative concentration. Fiber length is more significant in the control of t he extraction kinetics. In recirculation flow mode, the relative concentrat ion can be well described as an exponential function of time. The kinetic c onstant varies as a linear function of fiber length. Amine extractants (Ali quat 336, Alamine 336, Amberlite LA-2) are better extractants than TBP both from the kinetics and equilibrium standpoints. With Aliquat 336 the final Cr(VI) concentration tends to zero, while with TBP, the equilibrium is cont rolled by the volume of the extractant.