Degradation of Methylene Blue by RF Plasma in Water
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Radio frequency (RF) plasma in water was used for the degradation of methylene blue. The fraction of decomposition of methylene blue and the intensity of the spectral line from OH radical increased with RF power. RF plasma in water also produced hydrogen peroxide. The density of hydrogen peroxide increased with RF power and exposure time. When pure water (300 mL) is exposed to plasma at 310 W for 15 min, density of hydrogen peroxide reaches to 120 mg/L. Methylene blue after exposed to plasma degraded gradually for three weeks. This degradation may be due to chemical processes via hydrogen peroxide and tungsten. The comparison between the experimental and calculated spectral lines of OH radical (A–X) shows that the temperature of the radical is around 3,500 K. Electron density is evaluated to be ≃3.5 × 1020 m−3 from the stark broadening of the Hβ line.
KeywordsRadio frequency plasma In water Degradation AOPs
The present work was partially supported by Grants-in Aid from the Ministry of Education, Culture, Sports, Science and Technology of Japan (No. 17654118) (T. Maehara) and (No. 17560636) (H. Toyota). The authors thank Mr. H. Okumura for technical support.
- 2.Sharma AK, Locke BR, Arce P, Finney WC (1993) Hazard Waste Hazard Mater 10:209Google Scholar
- 5.Sahni M, Finnery WC, Locke BR (2005) J Adv Oxid Technol 8:105Google Scholar
- 7.Inoue M, Okada F, Sakurai A, Sakakibara M (2006) Ultrasonics Sonochem 13:313Google Scholar
- 9.Aoki H, Kitano K, Hamaguchi S (2007) Proceedings of 18th international symposium on Plasma Chemistry, Kyoto, Japan: 00339Google Scholar
- 14.Takahashi Y, Toyota H, Nomura S, Mukasa S (2007) Proceedings of 18th international symposium on plasma chemistry, Kyoto, Japan: 00133Google Scholar
- 15.Takai O (2007) Proceedings of 18th international symposium on plasma chemistry, Kyoto, Japan: 00254Google Scholar
- 17.Mašláni A, Sember V (2004) Proceedings on fourth international workshop and school towards fusion energy-plasma physics, Diagnostics, Applications Kudowa Zdroj, Poland: 669Google Scholar
- 18.Luque J, Crosley DR, (1999) “LIFBASE” Database and Spectral Simulation Program (Version 1.5), SRI International Report Mp 99-009Google Scholar
- 23.Griem HR (1964) Plasma spectroscopy. MacGrow-Hill, New YorkGoogle Scholar
- 24.Chase MW Jr, Davies CA, Downey JR Jr, Frurip DJ, McDonald RA, Syverud AN (1985) JANAF thermochemical tables, 3rd edn. American Chemical Society and the American institute of Physics for the National Bureau of Standards, New YorkGoogle Scholar
- 25.Seidell A, Linke WF (1965) Solubilities of inorganic and metal organic compounds, 4th edn. American Chemical Society, WashintonGoogle Scholar