Yukitoshi Takeshita*, Yoshiyuki Sato* and Shiro Nishi*

* NTT Lifestyle and Environmental Technology Laboratories

+ Correspondence should be addressed to Yukitoshi Takeshita:
(3-9-11, Midori-cho Musashino-shi, Tokyo 180-8585 Japan)

Abstract

To develop an environmentally benign technique for treatment of CCA-treated wood, the effects of temperature, pressure, and flow rate on the extraction efficiency in the extraction of heavy metals by using supercritical CO2 containing acetylacetone as a chelating agent were examined experimentally. It was found that high temperature, high pressure, and low flow rate greatly improved the extraction efficiency. Acetylacetone added as a chelating agent markedly enhanced the extraction yield, apparently due to the formation of metal-chelating compounds. This study suggests that metals contained in commercially used CCA-treated wood can be extracted by using supercritical CO2 with acetylacetone.

Key words: supercritical carbon dioxide, extraction, metal, wood, acetylacetone