Decomposition of Chlorofluorocarbon by Sonication

The sonolytic decomposition of chlorofluorocarbon (CFC 113) and several alternative compounds, such as HCFC 225ca, HCFC 225cb, and HFC 134a, in.aqueous solutions was investigated. The CFC 113 with a high volatility and a low solubility in water was rapidly decomposed with increasing sonication time. The decomposition rates were influenced by the initial concentration of CFC 113, the reaction temperature, and the gas/liquid phase volume ratio but were independant of the pH of solution. The predominant pathway of the decomposition of CFC 113 by sonication was not the oxidation by OH radicals but the pyrolysis with high temperature and pressure inside of the cavitation bubble. The pyrolysis in the cavitation bubble resulted in an almost complete mineralization of CFC 113 with the high efficient formation of inorganic products (Cl$^{[-10]}$ , F$^{[-10]}$ , CO, $CO_2$). The addition of zinc powder on the decomposition of CFC 113 by sonication caused an acceleration of the decomposition. Also, HCFCs and HFC 134a were found to be readily decomposed by the pyrolysis induced from the sonication.

초음파조사에 의한 염화불화탄소(CFC)의 분해