Black carbon enriches short-range-order ferrihydrite in Amazonian Dark Earth: Interplay mechanism and environmental implications

被引：10

作者：

Weng, Yi-Tse ^{[1
]}

Rathod, Jagat ^{[1
]}

Liang, Biqing ^{[1
]}

Wang, Chun-Chieh ^{[2
]}

Iizuka, Yoshiyuki ^{[3
]}

Tamura, Nobumichi ^{[4
]}

Chen, Chi-Liang ^{[5
]}

Lee, Yao-Chang ^{[6
,7
,8
]}

机构：

[1] Natl Cheng Kung Univ, Dept Earth Sci, Tainan, Taiwan

[2] Natl Synchrotron Radiat Ctr, Xray Imaging Grp, Hsinchu, Taiwan

[3] Acad Sinica, Inst Earth Sci, Taipei, Taiwan

[4] Lawrence Berkeley Natl Lab, Adv Light Source, Berkeley, CA USA

[5] Natl Synchrotron Radiat Ctr, Xray Absorpt Grp, Hsinchu, Taiwan

[6] Natl Synchrotron Radiat Ctr, Life Sci Grp, Hsinchu, Taiwan

[7] Natl Cent Univ, Dept Opt & Photon, Chungli, Taiwan

[8] Natl Tsing Hua Univ, Dept Chem, Hsinchu, Taiwan

来源：

SCIENCE OF THE TOTAL ENVIRONMENT | 2020年 / 725卷

关键词：

Amazonian Dark Earth; Biochar (BC); Organo-mineral interaction mechanism; Short-range-order (SRO) mineral; Ferrihydrite; XAS; SOIL ORGANIC-MATTER; IN-SITU; GOETHITE; BIOCHAR; STABILIZATION; FTIR; MINERALS; HEMATITE; FRACTIONS; ACID;

D O I：

10.1016/j.scitotenv.2020.138195

中图分类号：

X [环境科学、安全科学];

学科分类号：

08 ; 0830 ;

摘要：

Our study underpins the mechanism of organo-mineral interaction between black carbon (BC, biochar) and associated minerals in the historical BC-rich Amazonian Dark Earth (ADE) by using synchrotron-basedmicroscopic (TXM), microspectroscopic (mu FTIR) and spectroscopic (XAS and mu-diffraction) approaches. The BC-rich ADE contained over 100% more poorly crystalline minerals than the adjacent tropical soil. Linear combination fitting of k-spacing in the X-ray Absorption Spectra (XAS) revealed that ferrihydrite contributed to 81.1% of the Feminerals in BC. A small but distinct peakwas observed at 5.7 angstrom(-1) in the extended X-ray absorption fine structure k oscillation of BC, revealing the presence of Fe-C (including Fe-O-C) covalent bonds. No Fe-C path was yielded by the XAS fitting when an obvious peak downshift of the first (Fe-Fe-1) shell was observed, suggesting that the availability of inner-sphere Fe-C complexation was limited to the BC surface and interphase region. The main minerals for organo-mineral complexation were short-range-order (SRO) ferrihydrite on BC instead of cornersharing FeO6 octahedra. Compared to ADE, the coordination number of the first (Fe-Fe-1) and second (Fe-Fe-2) shell was higher in BC, revealing a higher degree of order in coordination between the neighboring Fe mineral crystals. Black C limited the progressive aging of amorphous Fe phases and greatly enriched SRO ferrihydrite in the redox-fluctuating and high-leaching environment. The transformation of SRO ferrihydrite into the more crystalline Fe oxides was controlled by the local pH environment. A strong signal from the complexed phenolic group (aryl-OH, 1241 cm(-1)) and a distinct band of inner- sphere complexation (Fe-aryl C, 13801384 cm(-1)) were identified in the FTIR spectra. The enrichment of poorly crystallineminerals can have positive feedback on the long-term stabilization of BC. The scale-up application of biochar to agricultural and ecological systems may have a long-lasting impact on the enrichment and transformation of the SRO minerals in the soil. (C) 2020 Elsevier B.V. All rights reserved.

引用

页数：12

共 82 条

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