Activation of persulfate with vanadium species for PCBs degradation: A mechanistic study
Activation of persulfate with vanadium species for PCBs degradation: A mechanistic study
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用钒物质激活过硫酸盐降解 PCB：机理研究
DOI：
10.1016/j.apcatb.2016.09.006
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发表时间：
2017-03-01
影响因子：
22.1
通讯作者：
Zhou, Dongmei
中科院分区：
文献类型：
--
作者：
Fang, Guodong;Wu, Wenhui;Zhou, Dongmei
首次研究了过硫酸盐(PS)和钒(V)对多氯联苯(2，4，4‘-三氯联苯[PCB28])降解的活化作用。结果表明，V_2O_3对PS分解PCB28具有较高的催化活性。即使在近中性的pH值(7.4)下，PCB28在V_2O_3/PS中也能被有效降解。用V2O3活化PS降解PCB28生成硫酸根阴离子(SO4中心点-)和羟基自由基(中心点OH)，并用电子顺磁共振(EPR)技术对其进行了表征。自由基猝灭研究表明，乙醇抑制了PCB28的降解，而叔丁醇通过与醇自由基还原脱氯促进了PCB28的降解。通过对V_2O_3/PS中PCB28降解中间产物的GC-MS分析，提出了PCB28的降解途径。阐明了PS的激活机制。结果表明，V(III)通过电子转移活化PS生成SO4中心点和V(IV)(VO2)，生成的V(IV)进一步将一个电子转移到PS中生成SO4中心点和V(V)(V6O13)。此外，VO2和V2O5均能激活PS降解PCB28，表明V2O5表面的过硫酸盐离子(S2O82-)还原V(V)可再生V(IV)。这些发现将有助于更好地了解天然存在的V矿物与PS之间的相互作用，并为PS的活化降解污染物提供一种新的活化剂。(C)2016爱思唯尔B.V.保留所有权利。
In the present study, the activation of persulfate (PS) with vanadium (V) species for PCBs (2,4,4'-trichlorobiphenyl [PCB28]) degradation was investigated for the first time. It was found that V2O3 exhibited high catalytic activity toward PS decomposition for PCB28 degradation. Even under near neutral pH (7.4), PCB28 was efficiently degraded in V2O3/PS. Sulfate radical anions (SO4 center dot-) and hydroxyl radicals (center dot OH) were produced from PS activation with V2O3 for PCB28 degradation, and were characterized with electron paramagnetic resonance (EPR) technique. Free radical quenching studies showed that ethanol inhibited PCB28 degradation, while tert-butyl alcohol enhanced PCB28 degradation via reductive dechlorination with alcohol radicals. The pathway of PCB28 degradation was proposed on the basis of GC-MS analysis of intermediates of PCB28 degradation in V2O3/PS. The mechanisms of PS activation are elucidated. It was found that V(III) in V2O3 activated PS to form SO4 center dot- and V(IV) (VO2) via electron transfer process, and the formed V(IV) further transferred an electron to PS to generate SO4 center dot- and V(V) (V6O13), which were supported with XRD analysis. Furthermore, both VO2 and V2O5 can activate PS for PCB28 degradation, indicating that V(IV) would be regenerated from the reduction of V(V) by persulfate ions (S2O82-) on the surface of V2O5 particles. These findings would help to better understand the interactions between naturally occurring V minerals and PS, and provide a novel activator for PS activation to degrade contaminants. (C) 2016 Elsevier B.V. All rights reserved.