WATER-POLLUTING ORGANIC SUBSTANCE REMOVAL METHOD

摘要

PROBLEM TO BE SOLVED: To provide a water-polluting organic substance removal method which oxidatively decomposes water-polluting organic substances and the like in treated water by using photocatalyst titanium oxide which is easily fabricated into various dosage forms and shapes required when used as a photocatalyst and baked at the high temperature of ≥500°C to control the ratio of an anatase-type crystal to a rutile type crystal.;SOLUTION: In the water-polluting organic substance removal method, the water-polluting organic substances and the like in the treated water are oxidatively decomposed by using the titanium oxide of which the ratio of the anatase-type crystal to the rutile type crystal is controlled and which is obtained by baking a titanium oxide precursor at the high temperature of ≥500°C. The titanium oxide precursor is obtained by repeating the following pH swing operation at least three times. The pH swing operation comprises an operation for adding a basic aqueous solution to a titanium-containing acidic aqueous solution to precipitate the titanium oxide precursor having a hydroxyl group, and then adding an acidic raw aqueous solution into the obtained titanium oxide precursor slurry to decrease the pH value to the dissolution region of the titanium oxide precursor and at the same time feeding additional raw material, and an operation for adding the basic aqueous solution to the titanium-containing acidic aqueous solution obtained by the above operation to increase the pH value to the precipitation region of the titanium oxide precursor.;COPYRIGHT: (C)2005,JPO&NCIPI