The effects of the co-existing compounds on the decomposition of micropollutants using the ozone/hydrogen peroxide process

The effect of co-existing compounds on the decompositions of three target compounds (i.e., 1,2,4-trichlorobenzene (TCB), 1,4-dioxane, and 17β-estradiol) using the ozone/hydrogen peroxide (O3/H2O2) process was investigated. Their reactivities toward HO• are assumed to be of the order of 109 /M · s. The decomposition rate of TCB was much higher during the O3/H2O2 process than during ozonation in the presence of bicarbonate ion, an inhibitor of radical chain reactions. 17β-Estradiol, a highly reactive target compound toward ozone, was decomposed at lower ozone dose than TCB and 1,4-dioxane, lowly reactive target compounds toward ozone, in the presence of humic acid. The reactivities of the co-existing compounds toward HO• were significantly related to the treatment efficiency of TCB when their concentrations as TOC were similar. The effect of humic acid, fulvic acid, and glucose, target compounds highly reactive toward HO•, on the decomposition of TCB was similar regardless of co-existing compounds. On the other hand, significantly lower effect of acetate and oxalate ions, target compounds lowly reactive toward HO•, on the decomposition of TCB was observed. Ozone dose required for the decomposition of TCB was inversely proportional to TCB concentration when HO• generated was greatly scavengedby co-existing compounds. On the other hand, ozone dose required for the decomposition of TCB was less affected by TCB concentration when HO• generated was used effectively for the decomposition of TCB.