Fixation of Cr(III) traces onto Haro river sand from acidic solution

The sorption of chromium(III) onto Hare river sand has been investigated as a function of sorptive solution composition, amounts of sorbent (10-500 mg) and sorbate (4.3310(-8)-5.1710(-6) M), shaking time (I-60 minutes) and temperature (15-35 degrees C). Maximum sorption has been achieved from 0.001M HCI solution using 50 mg of the sand and 20 minutes shaking time. The sorption data followed Freundlich and D-R isotherms. The sorption capacity of 0.4 mu mole . g(-1) and of sorption energy of 9.9 kJ . mole(-1) have been computed from D-R parameters. Thermodynamic parameters Delta H = 84.4 kJ . mole(-1), Delta S = 284.5 J . mole(-1) K-1 and Delta G = -3.32 kJ . mole-1 at 298 K have been evaluated. Fe(II), Al(III), citrate, berate, oxalate, tartrate and carbonate ions reduce the sorption significantly. Under similar experimental conditions Tc(VII), Re(VII), Sb(V) and Co(II) have very low sorption (<1%) and trivalent Eu and Sm have large distribution ratios. Haro river sand can be used to preconcentrate or to remove micro or submicro amounts of Cr(III) from very dilute solution and for the separation of Tc, Re and Sb from Cr, Eu and Sm.