Analytical Sciences

Extractability of Metals in Municipal Solid Wastes Fly Ash Using Supercritical CO₂ Containing Cyanex 302

Kayo SAWADA,*^,** Youichi ENOKIDA,* and Ichiro YAMAMOTO**

*EcoTopia Science Institute, Nagoya University, Furo-cho, Chikusa, Nagoya 464-8603, Japan
**Department of Materials, Physics and Energy Engineering, Nagoya University, Furo-cho, Chikusa, Nagoya 464-8603, Japan

The extraction of lead from fly ash produced during the thermal treatment of municipal solid wastes was studied using supercritical carbon dioxide (SC-CO₂) and Cyanex 302 (bis(2,4,4-trimethylpentyl)monophosphinic acid). The extraction of lead from the fly ash was carried out in a 5 cm³ internal volume reaction vessel under static extraction conditions at 323 K, and 24 MPa for 1 h. The extraction efficiencies of lead ranged from 4% to the total extraction under the conditions of 0.05 g fly ash with 2 cm³ Cyanex 302. There was a linear relationship between the extraction efficiencies of lead using the SC-CO₂ + Cyanex 302 and using a water-based method described by JLT13.

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