화학공학소재연구정보센터
Separation and Purification Technology, Vol.150, 215-222, 2015
Remediation HCHs POPs-contaminated soil by activated persulfate technologies: Feasibility, impact of activation methods and mechanistic implications
Hexachlorocyclohexanes (HCHs) waste stockpiles are the single largest source of POPs. Sites contaminated with high levels of HCHs pose serious threats to public health and environmental safety, but there remains a lack of proper environmentally sound solution. To provide guidance on this issue, the remediation of contaminated soil with high levels of gamma-HCH (similar to 800 mg/kg) by persulfate with three commonly applied field activation methods, namely heat activation at 40 degrees C, high pH and Fe(III)-EDTA activation, was investigated. The effects of activation method and persulfate dosage on the degradation and dechlorination of gamma-HCH were studied, and degradation pathways were proposed. The results show that heat-activated persulfate is highly effective for the remediation of gamma-HCH, achieving complete degradation and dechlorination of gamma-HCH in 14 days. Under high pH conditions, gamma-HCH rapidly dehydrochlorizes into trichlorobenzenes, which are further degraded by persulfate. On the other hand, persulfate alone at 20 degrees C and Fe(III)-EDTA activated persulfate are not effective for the degradation of gamma-HCH, due to limited generation of reactive radical species resulting from the inefficient activation of persulfate, and the competition of soil organic materials and Fe(III)-EDTA with gamma-HCH for reactive radicals. (C) 2015 Elsevier B.V. All rights reserved.