Degradation of Aqueous Phenol and Chlorinated Phenols by Ozone

摘要

The degradation of phenol, its chlorinated derivatives with ozone was studied. The compounds studied were phenol (Ph), 4 – chlorophenol (4- CPh) and 2,4 – dichlorophenol (2,4-DCPh). The kinetic performance of each phenolic compound and their model mixture was examined. The pH influence over the decomposition dynamic for different phenolic compounds in the range of 2 – 12 was investigated. An increase of the decomposition rate when we had a pH increasing was observed. In the studied range of the pH, phenol and chlorophenols ozonation proceeds rapidly. The UV absorbency was used for the preliminary control of the decomposition degree. The HPLC analysis was realized to identify the intermediates and final products formed during the ozonation. It was shown that the basic intermediates are muconic and fumaric acids, malonic and maleic acids and having a very small content of catechol (less than 1%). The final products are basically oxalic acid (90%) and formic acid. Intermediates and final products of the ozonation have been measured as a function of time using HPLC. Furthermore, the intermediates and final decomposition products obtained by different pH were compared. According to the identification results, a possible mechanism of the ozonation by the reaction of hydroxylation and dechloration in the early stage was proposed.