The reaction mechanism and pathway of the ozonation of 2,4,6-trichlorophenol(2,4,6-TCP)in aqueous solution were investigated.The removal efficiency and the variation of H_(2)O_(2),Cl^(−),formic acid,and oxalic acid we...The reaction mechanism and pathway of the ozonation of 2,4,6-trichlorophenol(2,4,6-TCP)in aqueous solution were investigated.The removal efficiency and the variation of H_(2)O_(2),Cl^(−),formic acid,and oxalic acid were studied during the semi-batch ozonation experiments(con-tinuous for ozone gas supply,fixed volume of water sample).The results showed that when there was no scavenger,the removal efficiency of 0.1 mmol/L 2,4,6-TCP could reach 99%within 6 min by adding 24 mg/L ozone.The reaction of molecular ozone with 2,4,6-TCP resulted in the formation of H2O2.The maximal concentration of H_(2)O_(2) detected during the ozonation could reach 22.5%of the original concentration of 2,4,6-TCP.The reaction of ozone with H_(2)O_(2) resulted in the generation of a lot of OH·radicals.Therefore,2,4,6-TCP was degraded to formic acid and oxalic acid by ozone and OH·radicals together.With the inhibition of OH·radicals,ozone molecule firstly degraded 2,4,6-TCP to form chlorinated quinone,which was subsequently oxidized to formic acid and oxalic acid.Two reaction pathways of the degradation of 2,4,6-TCP by ozone and O_(3)/OH·were proposed in this study.展开更多
基金This work was supported by the China Postdoctoral Science Foundation and the National Natural Science Foundation of China(Grant No.50325824).
文摘The reaction mechanism and pathway of the ozonation of 2,4,6-trichlorophenol(2,4,6-TCP)in aqueous solution were investigated.The removal efficiency and the variation of H_(2)O_(2),Cl^(−),formic acid,and oxalic acid were studied during the semi-batch ozonation experiments(con-tinuous for ozone gas supply,fixed volume of water sample).The results showed that when there was no scavenger,the removal efficiency of 0.1 mmol/L 2,4,6-TCP could reach 99%within 6 min by adding 24 mg/L ozone.The reaction of molecular ozone with 2,4,6-TCP resulted in the formation of H2O2.The maximal concentration of H_(2)O_(2) detected during the ozonation could reach 22.5%of the original concentration of 2,4,6-TCP.The reaction of ozone with H_(2)O_(2) resulted in the generation of a lot of OH·radicals.Therefore,2,4,6-TCP was degraded to formic acid and oxalic acid by ozone and OH·radicals together.With the inhibition of OH·radicals,ozone molecule firstly degraded 2,4,6-TCP to form chlorinated quinone,which was subsequently oxidized to formic acid and oxalic acid.Two reaction pathways of the degradation of 2,4,6-TCP by ozone and O_(3)/OH·were proposed in this study.
