Aminopolycarboxylic acids modified oxygen reduction by zero valent iron: Proton-coupled electron transfer, role of iron ion and reactive oxidant generation.
Aminopolycarboxylic acids modified oxygen reduction by zero valent iron: Proton-coupled electron transfer, role of iron ion and reactive oxidant generation.
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DOI：
10.1016/j.jhazmat.2022.128402
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发表时间：
2022-02
影响因子：
13.6
通讯作者：
Qi Wang;Yuwei Pan;Wenyang Fu;Huizhong Wu;Ming-hua Zhou;Ying Zhang
中科院分区：
文献类型：
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作者：
Qi Wang;Yuwei Pan;Wenyang Fu;Huizhong Wu;Ming-hua Zhou;Ying Zhang
研究了fe0在硝基三乙酸（NTA）、乙二胺-N，N ' -二琥珀酸（EDDS）和乙二胺四乙酸（EDTA）三种氨基聚羧酸（CAs）存在下的氧还原反应（ORR）对磺胺乙烷（SMT）的降解。在最佳条件下，Fe0/EDDS/O2、Fe0/EDTA/O2和Fe0/NTA/O2体系的SMT去除率分别为58.2%、75.3%和93.8%，远高于Fe0/O2体系的1.36%。CAs促进了表面结合Fe2+（三键Fe2+）和溶解铁离子的生成。在NTA和EDTA体系中，通过双电子传递途径的ORR主要负责生成h2o2，而在EDDS体系中，单电子ORR是生成h2o2的主要来源。•Fe2+与h2o2均相反应生成的OH是SMT降解的主要物质。Fe0/EDDS/O2比Fe0/EDTA/O2和Fe0/NTA/O2产氧量高；然而，自由基对SMT去除的贡献微不足道。CAs的笼化效应可能是影响Fe2+与O2反应速率的主要因素。CAs提供质子加速电子转移，生成三键fe2 +，从而去除污染物。本研究对于揭示fe0螯合体系中ORR的机制具有重要意义。
The oxygen reduction reaction (ORR) activated by Fe0in the presence of three aminopolycarboxylic acids (CAs), i.e. nitrilotriacetic acid (NTA), ethylenediamine-N,N′-disuccinic acid (EDDS) and ethylenediaminetetraacetic acid (EDTA), for the degradation of sulfamethazine (SMT) was investigated. At optimum conditions, Fe0/EDDS/O2, Fe0/EDTA/O2and Fe0/NTA/O2systems presented SMT removal of 58.2%, 75.3% and 93.8%, respectively, being much higher than that in the Fe0/O2system (1.36%). The generation of surface-bound Fe2+(triple bondFe2+) and dissolved iron ion was enhanced by CAs. ORR through a two-electron transfer pathway was mainly responsible for H2O2generation in NTA and EDTA systems, while a single-electron ORR was the major source for producing H2O2in EDDS system. •OH produced by the homogeneous reaction of Fe2+and H2O2was the main species for SMT degradation. Fe0/EDDS/O2produced more1O2than Fe0/EDTA/O2and Fe0/NTA/O2; however, the radical contributed negligibly to SMT removal. The caging effect of CAs might be a major factor influencing the reaction rate of Fe2+and O2. CAs provided protons to accelerate the electron transfer, the production of triple bondFe2+and thus the contaminant removal. This study is of great significance for revealing ORR mechanisms in the Fe0-chelate system.