Division of Environmental Physics - User: student
Faculty of Mathematics, Physics and Informatics, Comenius University Bratislava

Acetaldehyde Treatment in Foaming Column

Pawłat J., Hensel K., Yamabe C., Mizuno A.
30th IEEE International Conference on Plasma Science ICOPS 2003, Cheju (Korea), June 2-5, 276 (2003)

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Abstract:

AOT (Advanced Oxidation Technologies) are known assafe and effectual in disinfection, and treatment of many organiccompounds. Acetaldehyde (CH3CHO) is a flammable,volatile, colorless liquid with a nice fruity odor if diluted. Itis miscible in water and common organic solvents as acetone,toluene, etc. It might be a primary or secondary pollutant asit is widely used in production of many chemical compounds,and in the dye, cosmetics, leather, rubber and food industries.It is anticipated to be a human carcinogen.In this paper the application of electrical discharge in thefoaming system for the ethanal removal was presented. Foamwas formed with mixtures of oxygen, acetaldehyde and purewater in the special flow regime of media, using the diffusers. To decrease the pressure drop on the diffuser, the metalgrid replaced the diffuser and small amount of common surfactantwas dosed in some experiments.The main reactor was a cylindrical column with a ceramicdiffuser, which was placed perpendicularly to the flow directionof media. Gas was added in the lowest part of the apparatususing gas inlet. The outlet was located in the upperpart of the reactor. The electrodes of stainless steel consistedof the inner tube electrode and the outer tube electrode. Thepulse power source was operated at 250 Hz.Hydrogen peroxide, OH radicals, small amounts of gaseousand dissolved ozone were generated in foam due to the electricaldischarge. The concentration of hydrogen peroxidewas measured using HACH Hydrogen Peroxide Test Kit. Theamount of H2O2 ranged 55 mg/l and was highest for the limitsof gas flow, when foam was most stable and uniform. Thesmall amount of gaseous ozone was also detected. The concentrationof acetaldehyde decreased in the tested samplesdue to the superposition effect of simultaneous application ofvarious oxidants formed in foam by the electrical discharge.Generally, with the low gas flow rate and the higher appliedvoltage concentration of oxidants increased as expected.For the high gas flow rate with the same total power arcingphenomena took place.