METAL ION SORPTION TO BIRCH AND SPRUCE WOOD

Abstract

Sorption of metal ions from aqueous solutions to birch wood and spruce heartwood and sapwood has been studied. Functional groups in wood were determined by acid-base titrations. The sorption of metal ions to wood of the different tree species was investigated by a column chromatographic technique. The mechanism of sorption is mainly ion exchange by complexation of metal ions to the functional groups, e.g. carboxyl groups and phenolic hydroxyl groups, in the wood phase. By combination of the sorption experiments with four different metal ion mixtures, the following affinity order was established for spruce sapwood particles: Fe 3+ >>Pb 2+ >>Cu 2+ >>Fe 2+ >Cd 2+ >Zn 2+ >Ni 2+ >Mn 2+ Ca 2+ Sr 2+ Ba 2+ >>Mg 2+ >>K + >Na + Li +