六価クロム(Cr^<6+>)含有廃棄物の還元化処理法の検討

概要

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The characteristics of a reduction of the hexavalent chromium(Cr^<6+>) with an extractives of woody powder were investigated. The extractives was made by using a following method. We heated the powders of a Japanese ceder in a water at 300℃-400℃. Then we were treated them into the hot(40-50℃) alkaline solution (NaCO_<3 aq>.). In order to certify the reduction of its function for the wastes contained the hexavalent chromium (Cr^<6+>), the reduction characteristics was examined by measuring the reductive ratios of a hexavalent chromium(Cr^<6+>). The Cr^<6+> ions were measured by using Diphenylcarbonohydrazide reagent. The values of pH and EC(electrical conductivity) of the Extractives were showed around a neutrality as pH=7.30 and EC=79.2mS/m. The remarkable reductive ratios of a Cr^<6+> ions(66.7%) with a solution treated with the oyster shells(25wt%) on a hexavalent chromium (Cr^<6+>) standard solution (1.0ppm). The remarkable reductive ratios of Cr^<6+> ions(90.0%) on the residue of a boiler using woods were obtained through the treatment with the woody extractives on the wastes contained a Cr^<6+> ions. These results suggest that which a Cr^<6+> ions include the wastes is formed a complex compounds [trivalent chromium(Cr^<3+>)-organic ligand] by a reductive reaction. Those properties might be caused by the organic compounds in the extractives of woody powder.
北海道工業大学の論文
2007-03-26