Hisao Matsumoto

Decomposition of Ketones in Water by Ozone Treatment and UV Irradiation

There is a possibility that aliphatic ketones are contained in waste from chemical laboratories, painting factories and so on. Therefore, the polluted water must be treated in order to remove them. In this report each 5 mM ketone in the 0.05 M phosphate buffer (pH 7.0) was treated by ozone alone, UV irradiation alone or ozone + UV irradiation, and their degradation pathways were investigated from the decomposition products. Sample ketones were very rapidly decomposed by ozone + UV, and the main pathway was considered to have released a longer side-chain prior to the other shorter chain. Released alkyl chains were oxidized to aldehydes and fatty acids, and they were decomposed according to each decomposition pathway. The other pathway was production of keto acids by oxidation at the terminal methyl group. Ketones themselves were decomposed slowly by ozone alone, but decomposition by UV alone occurred more rapidly than by ozone alone. The reason was considered ketones have UV absorption about 254 nm which is the irradiation wavelength of a low pressure mercury lamp. The ketones having a longer side-chain were decomposed faster than a short side-chain like acetone. But total organic carbon (TOC) removal (%) was lowered in ketones having side-chains of larger carbon numbers.