Statistical Study of Instantaneous Demand of para-Chlorobenzoic Acid as an Ozone/Hydroxyl Radical Probe Compound

Abstract

Ozone dissolution is a chain reaction process due to ozone decomposition which generates hydroxyl radicals that can be detected by using pCBA (para-Chlorobenzoic Acid) as a probe compound. However, reported reactions for pCBA and OH radicals have not been sufficiently described statistically to show its permanence. In order to investigate this, two different stages of batch experiments were conducted to study the reactions among generated OH radicals, pCBA and t-butanol. In addition, an instantaneous demand, plus rapid and gradual phases of reactions for pCBA were also observed in this study. This study attained a cause-and-effect linear empirical correlation equation between degraded pCBA and ozone concentration, which indicated chain reactions generating OH radicals. The significance of correlation is confirmed by conducting a two-tailed hypothesis test. Additionally, due to free available OH radicals in the set conditions, an instantaneous demand of probe compound was confirmed by using the goodness-of-fit test. Observed instantaneous demand was about 83 to 55% for the initial concentration ratios of pCBA to ozone being 0.160 to 0.232, respectively. Calculated pseudofirst-order rate constants for pCBA are from 1.345 to 4.677 min−1 and 0.218 to 0.944 min−1 for rapid and gradual degradation phases, respectively.