氧化还原
铁质
化学
活性氧
氧气
铁
生物地球化学循环
环境化学
零价铁
土壤水分
无机化学
生态学
生物
生物化学
吸附
有机化学
作者
Guoqiang Zhao,Mengxi Tan,Binbin Wu,Xiaoshan Zheng,Ruoxuan Xiong,Baoliang Chen,Andreas Kappler,Chiheng Chu
标识
DOI:10.1021/acs.est.3c02302
摘要
Reactive oxygen species (ROS) play key roles in driving biogeochemical processes. Recent studies have revealed nonphotochemical electron transfer from redox-active substances (e.g., iron minerals) to oxygen as a new route for ROS production. Yet, naturally occurring iron minerals mainly exist in thermodynamically stable forms, restraining their potential for driving ROS production. Here, we report that tide-induced redox oscillations can activate thermodynamically stable iron minerals for enhanced ROS production. •OH production in intertidal soils (15.8 ± 0.5 μmol/m2) was found to be 5.9-fold more efficient than those in supratidal soils. Moreover, incubation of supratidal soils under tidal redox fluctuations dramatically enhanced •OH production by 4.3-fold. The tidal hydrology triggered redox alternation between biotic reduction and abiotic oxidation and could accelerate the production of reactive ferrous ions and amorphous ferric oxyhydroxides, making thermodynamically stable iron minerals into redox-active metastable iron phases (RAMPs) with reduced crystallinity and promoting surface electrochemical activities. Those RAMPs displayed enhanced redox activity for ROS production. Investigations of nationwide coastal soils verified that tide-induced redox oscillations could ubiquitously activate soils for enhanced ROS production. Our study demonstrates the effective formation of RAMPs from redox oscillations by hydrological perturbations, which provides new insights into natural ROS sources.
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