Sorption potential of Haro river sand for the removal of antimony from acidic aqueous solution

The sorption of antimony (V) from 9.55 × 10−7 to 9.55 × 10−5 mol dm−3 on the sand of Haro river (10 mg-1 g) has been investigated to optimize the maximum adsorption with respect to the selection of an appropriate electrolyte, shaking time, concentration of antimony and amount of sand. Maximum sorption of antimony (9.53 × 10−7 mol dm−3) from 0.3 mol dm−3 nitric acid solution has been achieved after 10 min shaking at a v/w ratio of 450 cm3 g−1. Among the ions tested, EDTA, citrate, sulphite, thiosulphate, iodide, Zr(IV), tartrate and fluoride reduce the sorption drastically whereas Al(III) and Pb(II) enhance the sorption significantly. Under optimal conditions chosen for antimony, larger distribution ratios are obtained for Ru(III) and Ni(II) whereas Sn(IV), Cu(II) and Fe(III) have shown substantial sorption. Zn(II), Cs(I) and Cr(III) are sorbed to a lesser extent (<5%). These elements can be separated from Sb(V), Ni(II) and Ru(III) using this sand as a column bed. The sorption data followed Freundlich and D---R isotherms over the entire concentration range of antimony investigated. The values of 1/n = 0.7 and of A = 64.5 μmol g−1 have been computed for the sorption system. The D---R parameters yielded the values: Cm = 16.7 μmol g−1, B = −0.004195 mol2 kJ−2 and E = 10.9 KJ mol−1. The sorption on the sand can be exploited for the preconcentration and removal of trace concentrations of antimony including radioactive isotopes from aqueous solutions or natural waters as well as from industrial and radioactive process waste water.