For the destruction of toxic chlorinated organic compounds, this study proposes improved supercritical water oxidation method (multistep oxidation) using sodium nitrate as an oxidizer. This method solves the problems involved in the existing supercritical water oxidation method. Multistep oxidation means that NaNO3 is oxidized to N2 via NaNO2 and NO. Toxic and hard to destroy organic substances like para-dichlorobenzen(4-DCBz), polychlorinate biphenyl(PCB) ware oxidized to non toxic substances in a condition, in which rapid pressure and temperature rise is restrained as much as possible. 4-dichlorobenzene(4-DCBz) and Polychlorinate biphenyl(PCB) in condition(450℃, pw=0.25g/cm3, 30min) Was discomposed perfectly.

Attempts have been made to use Supercritical fluids for industrial purpose in a variety of fields and some of them, are already in practice. However, basic chemical properties of supercritical fluids have not been understood well. The present paper presents the results of physicochemical studies on Supercritical fluids as well as the application of supercritical fluids to industry. The detail is as follows PCB and organic compounds.