Studies On Photocatalytic Degradation And Photolytic Degradation Of Chloroacetic Acids

Chloroacetic acids are one class of disinfection by-products with high carcinogenic risk. And the Dichloroacetic Acid and Trichloroacetic Acid are the main carcinogenic risk substances. The researches of Photocatalytic degradation and photolytic degradation of chloroacetic acids have been studied due to their unsafety to the drinking water. There is a conversion efficiency comparison about the two degradation methods. The possible reaction mechanisms of the photolytic degradation of chloroacetic acids are proposed. The kinetic equations of the degradation processes are educed. The effects of the acidity and alkaline initial condition to the conversion efficiency are concerned. The variation rules of pH values are explored.It has been shown that the Photocatalytic degradation conversion efficiency of Monochloroacetic Acid and Dichloroacetic Acid are both higher than photolytic degradation, but for Trichloroacetic Acid the Photocatalytic degradation conversion efficiency is lower than photolytic degradation. The aqueous electrons play an important role in the photolytic degradation of chloroacetic acids processes, and the possible reaction mechanisms are the free radical reactions aroused by the aqueous electron. The study confirmed that the kinetic equation of Photocatalytic degradation and photolytic degradation of chloroacetic acids processes are both followed one order reaction. The different acidity and alkaline initial conditions have different effects on the Photocatalytic degradation and photolytic degradation of chloroacetic acids processes, the acidity initial condition is good for the degradation. The pH values have always been changed and became lower during the Photocatalytic degradation and photolytic degradation processes. It can be seen from the results that the conversion efficiencies of photolytic degradation of chloroacetic acids are also quite high and the photolytic degradation method is more convenient and cheaper than the Photocatalytic degradation method. It is supposed that this research will give the new thought and approach to the reduction of the disinfection by-products in drinking water.