Purification treatment for iron composite particles of soil and groundwater that has been contaminated with organic halogen compounds, to a process for the preparation thereof, the iron purification agent comprising the composite particles, their preparation and purification treatment of soil and groundwater that has been contaminated with organic halogen compounds way

摘要

PPROBLEM TO BE SOLVED: To provide a purifying agent for efficiently and lastingly treating an aliphatic organohalogen compound or an aromatic halogen compound contained in soil or ground water to reduce the load applied to environment to the utmost. PSOLUTION: An iron composite particulate powder for purifying soil or ground water polluted with the organohalogen compound is suppressed in the elution of impurities and contains 30 to 99 wt% of -Fe. This iron composite particulate powder is obtained by a method wherein a suspension containing a ferrous salt-containing precipitate, which is obtained by adding an alkali hydroxide or alkali carbonate aqueous solution to a purified aqueous solution containing a ferrous salt, is oxidized to obtain a goethite particulate powder, this goehthite particulate power or a hematite particulate powder obtained by dehydrating the goehthite particulate powder under heating is reduced under heating to produce an iron particulate powder which is, in turn, taken out into water without forming a surface oxidized film on the iron particulate powder in a gaseous phase and the surface oxidized film is subsequently formed on the surfaces of the particle of the iron particulate powder in water before the iron particulate powder is dried. PCOPYRIGHT: (C)2004,JPO