DEGRADATION OF CHLOROETHENES IN AQUEOUS SOLUTION BY ULTRASOUND

Among several types of pollutants, chlorinated compounds are routinely the subject of sonochemical studies to investigate the environmental applications of this technology. C1 chlorinated organocompounds (CHCl3, CH2Cl2, CCl4) and C2 compounds (1,1,1 trichloroethane, tetrachloroethylene (PCE), hexachloroethane, 1, 1, 2, 2 tetrachloroethane and specially trichloroethylene) have been also studied, particularly in respect of the influence of ultrasonic frequency on the chemical processes and their kinetics[1], Chlorinated aromatic compounds have been also studied, including chlorotoluenes[2], p-chlorobenzoic acid [3], PCBs [4], especially chlorobenzenes [5], and chlorophenols[6]. Although perchloroethylene (PCE) remains a widely used solvent in many areas of industry and has been reported also to occur as a major intermediate in the degradation of other chlorinated compounds [7], to our knowledge, there has been no extensive study on the sonochemical degradation of this compound. In one report Bhatnagar et al. [8] related kinetics to the ultrasonic frequency (20 kHz) and vapor pressure of the compound, and showed that: (i) pH and temperature had little effect upon the destruction rate of the compound (and in any case vapor pressure does not correlate to the destruction rate for C2 compounds such PCE), (ii) nonspecificity of the process wit