Fenton Degradation of Highly Concentrated Fe(III)-EDTA in the Liquid Waste Produced by Chemical Cleaning of Nuclear Power Plant Steam Generators

An advanced oxidation process catalyzed by iron ions in the presence of hydrogen peroxide, the so-called Fenton's reaction, has been applied to the treatment of steam generator chemical cleaning waste containing highly concentrated iron(III)- ethyl-enediaminetetraaceticacid (Fe(III)-EDTA) of 70000 mg/L. The experiments for the degradation of Fe(III)-EDTA were carried out not only with a simulated waste, but also with the real one. The effect of pH and the amount of hydrogen peroxide added to the waste on the degradation was examined, and the results were discussed in several aspects. The optimal pH to maximize the degradation efficiency was dependent on the amount of hydrogen peroxide added to the waste. i.e., when the amount of hydrogen peroxide was different, maximum degradation efficiency was obtained at different pH's. The optimal amount of hydrogen peroxide relative to that of Fe(III)-EDTA was found to be 24.7 mol ($H_{2}O_{2}$)/mol (Fe(III)-EDTA) at pH around 9.

펜톤 반응을 이용한 원전 증기발생기 화학세정 폐액의 고농도 Fe(III)-EDTA 분해

본 연구에서는 70000 mg/L 가량의 고농도 철(III)-에틸렌디아민테트라아세트산(Fe(III)-EDTA)을 함유하고 있는 원전 증기발생기 화학 세정 폐액의 처리를 위해 펜톤 반응을 사용하였다. Fe(III)-EDTA 분해실험은 모사 폐액 뿐 아니라 실제 폐액을 가지고도 수행되었다. 폐액에 주입된 과산화수소의 양과 폐액의 pH가 Fe(III)-EDTA 분해에 미치는 영향이 정량적으로 평가되었고, 다양한 측면에서 고찰되었다. 분해효율이 최대가 되는 최적의 pH는 폐액에 주입된 과산화수소의 양에 의존하였다. 즉, 폐액에 주입된 과산화수소의 양이 다를 때 최대 분해효율이 얻어지는 pH가 달랐다. Fe(III)-EDTA의 분해를 위한 적정 조건은 폐액의 초기 pH가 9이고 과산화수소 주입량이 24.7 mol ($H_{2}O_{2}$)/mol (Fe(III)-EDTA)일 때였다.