Redox Properties of Pyrogenic Dissolved Organic Matter (pyDOM) from Biomass-Derived Chars
Redox Properties of Pyrogenic Dissolved Organic Matter (pyDOM) from Biomass-Derived Chars
复制标题
生物质炭中热解有机物 (pyDOM) 的氧化还原特性
DOI：
10.1021/acs.est.1c02429
复制
发表时间：
2021
影响因子：
11.4
通讯作者：
Sander, Michael
中科院分区：
文献类型：
--
作者：
Xu, Wenqing;Walpen, Nicolas;Keiluweit, Marco;Kleber, Markus;Sander, Michael
煤焦在环境中无处不在，并释放大量的氧化还原活性热解溶解有机物（pyDOM）。然而，pyDOM的氧化还原性质仍然很难表征。这项工作提供了一个系统的评估的数量和氧化还原特性的pyDOM释放在中性pH值从热解木材和草原料从200至700 °C共14焦。随着热解温度的升高，热解产物中pyDOM的释放量逐渐减少，反映了热解产物的凝聚程度增加和极性降低。使用流动注射分析结合电化学检测，我们证明了电子给容量（EDCpyDOM;高达6.5 mmole-·gC-1）高于电子接受容量（EACPyDOM;高达1.2 mmole-·gC-1）的所有pyDOM标本。的光学性质和低金属含量的pyDOM牵连的酚类和醌类作为主要的氧化还原活性部分。漆酶对选定的pyDOM进行氧化，导致EDCpyDOM减少1.57 mmole·gC-1，EACPyDOM增加0.25 mmole·gC-1，表明推测的酚部分发生了很大程度上不可逆的氧化。相同pyDOM的非介导电化学还原导致EDCpyDOM增加0.17 mmole·gC-1，EACPyDOM减少0.24 mmole·gC-1，与醌部分的大部分可逆还原一致。我们的研究结果意味着，pyDOM是一个重要的溶解氧化还原活性相在环境中，需要考虑评估和建模地球化学氧化还原过程和污染物的氧化还原转化，特别是在富含焦炭的环境。
Chars are ubiquitous in the environment and release significant amounts of redox-active pyrogenic dissolved organic matter (pyDOM). Yet, the redox properties of pyDOM remain poorly characterized. This work provides a systematic assessment of the quantity and redox properties of pyDOM released at circumneutral pH from a total of 14 chars pyrolyzed from wood and grass feedstocks from 200 to 700 °C. The amount of released pyDOM decreased with increasing pyrolysis temperature of chars, reflecting the increasing degree of condensation and decreasing char polarity. Using flow-injection analysis coupled to electrochemical detection, we demonstrated that electron-donating capacities (EDCpyDOM; up to 6.5 mmole–·gC–1) were higher than electron-accepting capacities (EACpyDOM; up to 1.2 mmole–·gC–1) for all pyDOM specimens. The optical properties and low metal contents of the pyDOM implicate phenols and quinones as the major redox-active moieties. Oxidation of a selected pyDOM by the oxidative enzyme laccase resulted in a 1.57 mmole–·gC–1decrease in EDCpyDOMand a 0.25 mmole–·gC–1increase in EACpyDOM, demonstrating a largely irreversible oxidation of presumably phenolic moieties. Non-mediated electrochemical reduction of the same pyDOM resulted in a 0.17 mmole–·gC–1increase in EDCpyDOMand a 0.24 mmole–·gC–1decrease in EACpyDOM, consistent with the largely reversible reduction of quinone moieties. Our results imply that pyDOM is an important dissolved redox-active phase in the environment and requires consideration in assessing and modeling biogeochemical redox processes and pollutant redox transformations, particularly in char-rich environments.