UTILIZATION OF WASTE FE(III) CR(III) HYDROXIDE FOR REMOVAL OF CR(VI) AND FE(II) BY FIXED-BED SYSTEM/

Fe(III)/Cr(III) hydroxide, a waste sludge from fertiliser industry has been used for adsorption of Cr(VI) and Fe(II) from aqueous solution i n fixed bed method. Effects of parameters such as initial metal ion co ncentration and pH were studied at a flow rate of 10 ml/min of the wat er solution. The breakthrough curves are typical sigmoidal type ones a nd the results show that increase in metal ion concentration decreases the breakthrough volume. The breakthrough volume is higher at pH 5.0 (500 ml/5g) than at pH 5.7 (100 ml/5g) for Cr(VI) adsorption. The adso rption obeys the Bed Depth Service Time (BDST) model and the adsorptio n capacity values are presented.