Oxygen Limitation Accelerates Regeneration of Active Sites on a MnO2 Surface: Promoting Transformation of Organic Matter and Carbon Preservation,Environmental Science & Technology

当前位置： X-MOL 学术 › Environ. Sci. Technol. › 论文详情

Our official English website, www.x-mol.net, welcomes your feedback! (Note: you will need to create a separate account there.)

Oxygen Limitation Accelerates Regeneration of Active Sites on a MnO2 Surface: Promoting Transformation of Organic Matter and Carbon Preservation
Environmental Science & Technology ( IF 10.8 ) Pub Date : 2022-06-20 , DOI: 10.1021/acs.est.2c01868
Zhiqiang Wang ₁ , Hanzhong Jia ₁ , Haoran Zhao ₁ , Ru Zhang ₁ , Chi Zhang ₁ , Kecheng Zhu ₁ , Xuetao Guo ₁ , Tiecheng Wang ₁ , Lingyan Zhu _{1,

2}

Affiliation

Birnessite (δ-MnO₂) is a layered manganese oxide widely present in the environment and actively participates in the transformation of natural organic matter (NOM) in biogeochemical processes. However, the effect of oxygen on the dynamic interface processes of NOM and δ-MnO₂ remains unclear. This study systematically investigated the interactions between δ-MnO₂ and fulvic acid (FA) under both aerobic and anaerobic conditions. FA was transformed by δ-MnO₂ via direct electron transfer and the generated reactive oxygen species (ROS). During the 32-day reaction, 79.8% of total organic carbon (TOC) in solution was removed under anaerobic conditions, unexpectedly higher than that under aerobic conditions (69.8%), suggesting that oxygen limitation was more conducive to the oxidative transformation of FA by δ-MnO₂. The oxygen vacancies (O_V) on the surface of δ-MnO₂ were more exposed under anaerobic conditions, thus promoting the adsorption and transformation of FA as well as regeneration of the active sites. Additionally, the reaction of FA with δ-MnO₂ weakened the strongly bonded lattice oxygen (O_latt), and the released O_latt was an important source of ROS. Interestingly, a part of organic carbon (OC) was preserved by forming MnCO₃, which might be a novel mechanism for carbon preservation. These findings contribute to an improved understanding of the dynamic interface processes between MnO₂ and NOM and provide new insights into the effects of oxygen limitation on the cycling and preservation of OC.

中文翻译：

限氧加速 MnO2 表面活性位点的再生：促进有机物转化和碳保存

水钠锰矿（δ-MnO ₂）是一种广泛存在于环境中的层状锰氧化物，在生物地球化学过程中积极参与天然有机物（NOM）的转化。然而，氧对 NOM 和 δ-MnO ₂的动态界面过程的影响仍不清楚。本研究系统地研究了需氧和厌氧条件下δ-MnO ₂与富里酸（FA）之间的相互作用。FA被δ-MnO _2转化通过直接电子转移和产生的活性氧（ROS）。在 32 天的反应过程中，在厌氧条件下去除了 79.8% 的溶液中总有机碳 (TOC)，出乎意料地高于好氧条件下 (69.8%)，这表明氧气限制更有利于 FA 的氧化转化。 δ-MnO ₂。_{在厌氧条件下，δ-MnO 2}表面的氧空位（O _V ）更多地暴露，从而促进了FA的吸附和转化以及活性位点的再生。此外，FA 与 δ-MnO ₂的反应削弱了强键合的晶格氧 (O _latt )，释放出的 O _latt是 ROS 的重要来源。有趣的是，一部分有机碳（OC）通过形成MnCO ₃被保存下来，这可能是一种新的碳保存机制。这些发现有助于更好地理解 MnO ₂和 NOM 之间的动态界面过程，并为氧限制对 OC 循环和保存的影响提供新的见解。

更新日期：2022-06-20

点击分享查看原文

点击收藏

阅读更多本刊最新论文本刊介绍/投稿指南11