Hm. Cheung et S. Kurup, SONOCHEMICAL DESTRUCTION OF CFC-11 AND CFC-113 IN DILUTE AQUEOUS-SOLUTION, Environmental science & technology, 28(9), 1994, pp. 1619-1622
The results of a preliminary, proof-of-principle investigation of the
sonochemical destruction of the chlorofluorocarbons CFC 11 (fluorotric
hloromethane) and CFC 113 (trifluorotrichloroethane) in dilute aqueous
solution are reported. The chlorofluorocarbon solutions with an initi
al concentration of approximately 50 mg/L of the CFC were exposed to 2
0-kHz ultrasound with a power per unit volume of either 4.6 W/mL in a
batch reactor or 0.64 W/mL in a circulating reactor. Destruction was f
airly rapid with very little, less than 5%, of the CFCs undergoing vol
atilization. Destruction rates were slightly higher at 5 degrees C tha
n at 10 degrees C. This decrease in reaction rate with an increase in
solution temperature is common in sonochemistry. The solution pH decre
ased upon sonication, indicating the acidic species as a final halogen
acceptor for at least a portion of the Cl and F.