期刊
CHEMOSPHERE
卷 215, 期 -, 页码 827-834出版社
PERGAMON-ELSEVIER SCIENCE LTD
DOI: 10.1016/j.chemosphere.2018.10.080
关键词
Biochar; Electron storage capacity; Redox reversibility; Chemical oxidation/reduction; Rate-limiting step; Pore diffusion
资金
- Delaware Environmental Institute (DENIN)
Black carbon such as biochar has been shown to support microbial redox transformation by accepting and/or donating electrons. Electron storage capacity (ESC) is an important property that determines the capacity of a biochar to mediate redox processes in natural and engineered systems. However, it remained unclear whether a biochar's ESC is constant and reversible and if so to what extent, over what redox potential range ESC is distributed, and what fraction of the ESC is microbially accessible. In this study, we developed chemical methods that employed combinations of reductants and oxidants of different potentials - Ti(III) citrate, ferricyanide, dithionite, and dissolved O-2 - to measure the ESC of Soil Reef biochar, a wood-derived biochar that can serve as an electron donor or acceptor for Geobacter metallireducens. For a given oxidant reductant pair, the ESC obtained over multiple redox cycles was constant and fully reversible, though lower than that of the virgin biochar. Pore diffusion within biochar particles was rate-limiting and controlled the timescale for redox equilibrium. Results suggest that redox-facile functional groups in biochar were distributed over a broad range of potentials. The ESC measured using dithionite indicates approximately 22% of the biochar's reversible ESC was accessible to G. metallireducens. We propose that reversible ESC may be regarded as a constant and quantifiable property of black carbon. (C) 2018 Elsevier Ltd. All rights reserved.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据