Quinone-mediated dissimilatory iron reduction of hematite: Interfacial reactions on exposed {001} and {100} facets.
J Colloid Interface Sci
; 583: 544-552, 2021 Feb 01.
Article
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| MEDLINE
| ID: mdl-33035793
ABSTRACT
Although quinone-mediated bioreduction of iron oxides has been investigated extensively, little is known about the interfacial interactions between quinone and various exposed facets. In this study, the reduction of hematite {001} and {100} by Shewanella putrefaciens CN-32 with anthraquinone-2,6-disulfonate (AQDS) was investigated. The added AQDS can enhance the bioreduction of both hematite {001} and {100}, with hematite {001} showing a higher reduction degree than hematite {100}. No significant secondary iron oxides were found, but defects were observed in HR-TEM images. AQDS sorption was higher on hematite {001} (0.13 µM m-2) than hematite {100} (0.1 µM m-2). Electron transfer rate between hematite {001} and AQDS (19.6 s-1) was higher than hematite {100} (18.2 s-1). Tafel curves revealed that hematite {001} possesses lower resistance (3.5-2.4 Ω) than hematite {100} (4.1-2.9 Ω) with AQDS from 0 to 400 µM, indicating that hematite {001} is more favorable for electron transfer from cells or anthrahydroquinone-2,6,-disulfonate (AH2QDS) to Fe oxide. In addition to the well-known electron shuttling role of AQDS, the higher adsorption sites and electrochemical activity of hematite {001} over {100} jointly contributed to the enhanced iron bioreduction. The findings provide a mechanistic understanding of the interactions between quinone and various facets of iron oxides.
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01-internacional
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MEDLINE
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En
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J Colloid Interface Sci
Año:
2021
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Article