| Budget Amount *help |
¥5,330,000 (Direct Cost: ¥4,100,000、Indirect Cost: ¥1,230,000)
Fiscal Year 2014: ¥780,000 (Direct Cost: ¥600,000、Indirect Cost: ¥180,000)
Fiscal Year 2013: ¥2,210,000 (Direct Cost: ¥1,700,000、Indirect Cost: ¥510,000)
Fiscal Year 2012: ¥2,340,000 (Direct Cost: ¥1,800,000、Indirect Cost: ¥540,000)
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| Outline of Final Research Achievements |
Goethite was successfully synthesized from the iron-containing sulfuric acid solution or acid mine drainage (AMD) of the Matsuo abandoned mine using an autoclave apparatus at 0.15 MPa and 121 °C for 2 h. At pH 2.2, ultrasound irradiation (200 kHz) for 60 min was employed to oxidize As(III) to As(V) in various atmospheres for an As(III) concentration of 10 ppm. The oxidation ratio of As(III) to As(V) is quite high (90%) at pH 2.2 in ambient atmosphere. The ratio is close to those obtained for Ar (95%) and O2 (96%) atmospheres. This may be due to the high concentration of H+ in the solution. Finally, the removal of As(III) using ultrasound irradiation and goethite simultaneously was investigated. The removal ratio reached 95% after 60 min of irradiation. The dependence of As removal ratio on irradiation time is similar to that of the As(III) oxidation ratio. Goethite is thus a promising material for As adsorption using ultrasound oxidation in acidic conditions and ambient atmosphere.
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