The dechlorinating microscopic mechanism and transient spectra of aqueous CCl~4 was studied by using nanosecond laser flash photolysis (LFP). The transient absorption band (λ~m~a~x<300nm) of aqueous CCl~4 solution deaerated by N~2 was attributed to trichloromethyl radical (CCl~3^.) which decayed following 2nd-order kinetics with (2k/εl) equal to 6.34×10^6s^-^1, and the transient absorption band (λ ~m~a~x<320nm) of same solution deaerated by O~2 was attributed to peroxytrichloromethyl radical (CCl~3O~2^.) which decayed following 1st-order reaction kinetics with a rate constant of 1.9×10^4s^-^1. The transient absorption band around 330nm was attributed to solvated chlorine atom. C~2Cl~6 as photolysis product of aqueous CCl~4 solution without oxygen showed that CCl~4 cannot be degraded by photolysis and free radical hydrolysis process. COCl~2 as photolysis product of aqueous CCl~4 solution in the presence of oxygen was observed directly in the transient absorption spectra, which means that CCl~4 can be degraded by photooxidation process.

Key words: CARBON TETRACHLORIDE, LASER, PHOTOLYSIS, FREE RADICALS