Abstract
The use of supercritical fluid was tested for the purpose of developing an environmentally benign technique for metal extraction from CCA-treated waste wood. The effects of a chelating agent and extraction conditions on metal recovery were examined experimentally. The recovery for copper and chromium was relatively high but that for arsenic was very low. Metal recovery by pure supercritical carbon dioxide was very low because the affinity between carbon dioxide and metal seemed to be weak. However, it was significantly improved by adding acetylacetone as a chelating agent. The metals in wood were found to be extracted uniformly in all regions of a piece. It was also found that continuous addition of acetylacetone increased metal recovery compared with the one-time addition at the beginning.
