Sorption and desorption of chromate by wood shavings impregnated with iron or aluminum oxide

This study examined the impregnation of hybrid poplar shavings with Fe or Al oxide and their reactivity with Cr(VI). The shavings were impregnated with an average of 1.24 +/- 0.18 mmol Fe g(-1) or 1.51 +/- 0.17 mmol Al g(-1), and the impregnated Fe or All oxide was highly amorphous. Capacity of Cr(VI) sorption by impregnated shavings was high and rate of the sorption was rapid. While the freshly sorbed Cr on the Fe oxide-shavings was readily desorbed in 0.1 M NaOH, nine weeks of ageing reduced the desorbability to only 6.5% of the sorbed Cr. Extraction with 0.1 M NaOH remained feasible to recover most sorbed Cr from the Al oxide-shavings over the same ageing period. Impregnation of the shavings with Fe or Al oxide turns the wood waste into a product for removing Cr(VI) or other oxy-anions from wastewater. (C) 2007 Published by Elsevier Ltd.