Degradation and rates of reaction of estrone in an ozone/hydrogen peroxide batch treatment system.

摘要

Ozone/hydrogen peroxide batch treatment was utilized for the degradation of the steroidal hormone estrone. The competitive kinetics method was used to determine the rates of reaction for direct ozone and estrone (E1), and for hydroxyl radicals and estrone. Experiments were performed at three pH levels (4, 7, and 8.5) and at three different molar O3/H2 O2 ratios (1:2, 2:1, and 4:1), all at temperatures averaging 20°C.; It was found for the direct ozone-E1 reaction that rate constants ranged between 3.65 x 103 M-1s-1 at pH 4, O3/H2O2 = 1:2, and 2.32 x 107 M-1s-1 at pH 8.5, O 3/H2O2 = 2:1. By far, pH had the greatest influence on rate reaction, whereas O3/H2O2 ratio was found to be slightly statistically significant.; For the hydroxyl radical-E1 reaction, apparent rate constants ranged between 1.14 x 1010 M-1s-1 at pH 7, O3/H2O2 = 2:1, and 7.03 x 1010 M-1s-1 at pH 4, O3 /H2O2 = 2:1. Again, pH was statistically significant but O3/H2O2 ratio was not. The regression output for this group of experiments showed considerable noise and the possibility of an unknown regressor.; Overall, O3/H2O2 is shown to be an effective treatment for E1. It was found that pH is a statistically significant experimental factor and is more significant to direct ozone reactions than to hydroxyl radical reactions. The role of O3/H2O2 ratio in rate reactions is still unclear at this time.