Trace Iron as single-electron shuttle for interdependent activation of peroxydisulfate and HSO3-/O2 enables accelerated generation of radicals.
Trace Iron as single-electron shuttle for interdependent activation of peroxydisulfate and HSO3-/O2 enables accelerated generation of radicals.
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DOI：
10.1016/j.watres.2022.118935
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发表时间：
2022-08
期刊：
影响因子：
12.8
通讯作者：
Huabin Zeng;Yue Cheng;E. Repo;Xin Yu;Xueci Xing;Tao Zhang;Xuqun Zhao
中科院分区：
文献类型：
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作者：
Huabin Zeng;Yue Cheng;E. Repo;Xin Yu;Xueci Xing;Tao Zhang;Xuqun Zhao
在各种环境修复过程中，活性氧物质的产生通常需要引发剂，这需要高剂量的活化剂和下游处理以消除失活催化剂的积累。本文构建了一个利用微量铁同时激活HSO 3-/O2体系和过硫酸盐（PDS）氧化体系的耦合过程，其中铁离子（2 mg/L）由于氧化还原电位适中，从HSO 3-/O2体系向PDS氧化体系传递单电子（Fe 3 +/Fe 2+，+0.77 V）介于SO 3·−/HSO 3 −（+0.63 V）和PDS/SO 4·−（+2.01 V）之间。因此，苯酚降解迅速发生在一级动力学常数k1 =0.223 min− 1，这是由于在该过程中硫酸根自由基（SO 4·−）和羟基自由基（·OH）的加速产生。k1值几乎是脱氧条件下的6倍（0.040 min−1）。密度泛函理论表明，单电子穿梭在空间上分离了HSO 3 −的给电子活化和PDS的受电子活化，同时避免了HSO 3 −和S2 O 82 −通过直接双电子转移的“相互湮灭”。最后，利用原位产生的电子穿梭（铸铁管中溶解的铁），HSO 3 −/PDS试剂可以有效地抑制耐氯病原体，并定期抑制生物膜在配电系统内的再生或附近的传染病爆发。
The generation of reactive oxygen species generally requires initiators in various environmental remediation processes, which necessitates high dosage of activators and downstream treatment for eliminating the accumulation of deactivated catalysts. Herein, a coupled process was constructed using trace iron for simultaneously activating HSO3−/O2system and peroxydisulfate (PDS) oxidation system, where the iron ions (2 mg/L) transferred single-electron from the former system to the latter due to the moderate redox potential (Fe3+/Fe2+, +0.77 V) between the potentials of SO3·−/HSO3−(+0.63 V) and PDS/SO4·−(+2.01 V). Hence, the phenol degradation quickly occurred at a first-order kinetic constant ofk1=0.223 min−1due to the accelerated generation of sulfate radical (SO4·−) and hydroxyl radical (·OH) in the process. Thek1value was almost 6-fold of that in the deoxygenated condition (0.040 min−1). Density function theory reveals that the single electron shuttle spatially separates the electron-donating activation of HSO3−and electron-accepting activation of PDS, while avoiding the “mutual-annihilation” of HSO3−and S2O82−via direct two-electron transfer. Finally, utilizing thein-situgenerated electron-shuttle (dissolved iron from cast iron pipe), the HSO3−/PDS reagent could efficiently inactivate the chlorine-resistant pathogens and inhibits biofilm regrowth inside the distribution systems at regular intervals or infectious disease outbreak in a neighborhood.