Wednesday, November 15, 2006 - 11:00 AM

Chromate Sorption by Fe or Al Impregnated Wood Chips.

Shiou Kuo and Richard Bembenek. Washington State University, "7612 Pioneer Way, E", "7612 Pioneer Way, E", Puyallup, WA 98371, United States of America

Modification of wood waste could potentially transform this low cost material into a useful product for removal of contaminants from wastewater. This study produced a wood material impregnated with Fe or Al oxide and examined the potential of the material to remove chromate from solution. The results showed that Cr(IV) was rapidly sorbed from solution by the wood chip after impregnation with Fe or Al oxide. The capacity of the wood chip to retain Cr(IV) increased with increasing size of the Fe or Al impregnated chips as more Fe or Al oxide was impregnated. The freshly sorbed Cr could be easily desorbed with 0.1 M NaOH. Of the three kinetic equations tested, the pseudo second-order equation was the best in describing the rate of Cr(IV) sorption and desorption by the impregnated chip. Although ageing of the sorbed Cr on the impregnated chips increased substantially the stability or bonding strength of the sorbed Cr, the degree of the ageing effect was greater for the Fe than for the Al impregnated chip. It is unclear if the formation of mixed oxides of Fe and Cr was responsible for the elevation of the stability of sorbed Cr on Fe impregnated chip. The results emphasizes that wood waste could be easily converted to a product with high reactivity with Cr(IV) or other oxyanions.