In this study, the formation of hydroxyl radical and decomposition characteristics of bisphenol A (BPA) was investigated by quantifying hydrogen peroxide formed as a reaction by-product during the formation stage of hydroperoxyl radical. The direct oxidation reaction by ozone only decomposed BPA just like the Criegee mechanism under the condition where radical chain reactions did not occur. Non-selective oxidation reactions occurred under the conditions of pH 6.5 and 9.5 where radical chain reactions do occur, confirming indirectly the formation of hydroxyl radical. The decomposition efficiency of BPA by the added catalysts appeared in the order of O3/PAC ≥ O3/H2O2 > O3/high pH > O3 alone. 0.03~0.08 mM of hydrogen peroxide were continuously measured during the oxidation reactions of ozone/catalyst processes. In the case of O3/high pH process, BPA was completely decomposed in 50 min of the oxidation reaction, but reaction intermediates formed by oxidation reaction were not oxidized sufficiently with 29% of the removal ratio for total organic carbon (TOC, selective oxidation reaction). In the case of O3/H2O2 and O3/PAC processes, BPA was completely decomposed in 40 min of the oxidation reaction, and reaction intermediates formed by the oxidation reaction were oxidized with 57% and 66% of removal ratios for TOC, respectively (non-selective oxidation reactions).

본 연구에서는 하이드로퍼옥시 라디칼 생성단계에서 반응 부산물로 생성되는 과산화수소를 정량하여 수산화라디칼의 생성 및 비스페놀 A (BPA)의 분해특성을 조사하였다. 라디칼 연쇄반응이 일어나지 않는 조건에서는 Criegee mechanism 과 동일하게 오존에 의한 직접산화반응만이 BPA를 분해시키는 것으로 나타났다. 라디칼 연쇄반응이 일어나는 pH 6.5 및 9.5의 조건에서는 비선택적 산화반응이 일어나 수산화라디칼의 생성을 간접적으로 확인할 수 있었다. 투입된 촉매 에 의한 BPA의 분해효율은 O3/PAC ≥ O3/H2O2 > O3/high pH > O3 alone 공정 순으로 나타났다. 오존/촉매공정들의 산화 반응 동안에는 0.03~0.08 mM의 과산화수소가 지속적으로 측정되었다. O3/high pH 공정의 경우, BPA가 반응시작 50 min 만에 완전히 분해되었지만, TOC (총유기탄소) 제거율은 29%로 산화반응 중 생성된 중간물질을 충분히 산화시키지 못하는 것으로 나타났다(선택적 산화반응). O3/H2O2 및 O3/PAC 공정에서는 BPA가 반응시작 40 min 만에 완전히 분해되 었으며, TOC 제거율은 각각 57% 및 66% 정도로 반응 중간체들을 산화(비선택적 산화반응)시키는 것으로 나타났다.