Cited by 3,230Thermochemical Biomass Conversion ProcessesSoil Carbon and Nitrogen DynamicsAdsorption and biosorption for pollutant removal

Dynamic Molecular Structure of Plant Biomass-Derived Black Carbon (Biochar)

Open access
Keiluweit, Marco, Nico, Peter S., Johnson, Mark G., Kleber, Markus·2010·Environmental Science & Technology

Abstract

Char black carbon (BC), the solid residue of incomplete combustion, is continuously being added to soils and sediments due to natural vegetation fires, anthropogenic pollution, and new strategies for carbon sequestration ("biochar"). Here we present a molecular-level assessment of the physical organization and chemical complexity of biomass-derived chars and, specifically, that of aromatic carbon in char structures. Brunauer-Emmett-Teller (BET)-N(2) surface area (SA), X-ray diffraction (XRD), synchrotron-based near-edge X-ray absorption fine structure (NEXAFS), and Fourier transform infrared (FT-IR) spectroscopy are used to show how two plant materials (wood and grass) undergo analogous but quantitatively different physical-chemical transitions as charring temperature increases from 100 to 700 degrees C. These changes suggest the existence of four distinct categories of char consisting of a unique mixture of chemical phases and physical states: (i) in transition chars, the crystalline character of the precursor materials is preserved; (ii) in amorphous chars, the heat-altered molecules and incipient aromatic polycondensates are randomly mixed; (iii) composite chars consist of poorly ordered graphene stacks embedded in amorphous phases; and (iv) turbostratic chars are dominated by disordered graphitic crystallites. Molecular variations among the different char categories likely translate into differences in their ability to persist in the environment and function as environmental sorbents.

The claims and statistics of this paper haven’t been checked yet.

Run the check — free, no account needed. It reads the open-access text and checks the sources it cites.

A few free checks a day · papers already verified open instantly · results are public

Integrity signals

Registry

Crossref · 10.1021/es9031419

Cites

42 of 42 references verified0 citation errors · 0 not checkable

Statistics

Claims the paper makes

The claims and statistics of this paper haven’t been checked yet.

Run the check — free, no account needed. It reads the open-access text and checks the sources it cites.

A few free checks a day · papers already verified open instantly · results are public

Claims other papers make about this one

Each is checked against this paper’s own text: does it say what the citing paper says it does?

  • Woody biomass often has higher cellulose, hemicellulose and lignin contents than biomass from herbaceous or grass species.

    “Woody biomass often has higher cellulose, hemicellulose and lignin contents (Fig. 4) than biomass from herbaceous or grass species”

    From Biochar physicochemical properties: pyrolysis temperature and feedstock kind effects (2020) · cites this paper as Keiluweit et al. 2010

    The NEXAFS section attributes higher lignin content to woody material, but the Comparison of Precursor Materials section suggests grass has higher hemicellulose content—the opposite of the claim for that component. The cited passages do not establish that woody biomass has higher cellulose content. (LLM, conf=0.88)

    Checked by a reasoning model — may be wrong.

    Experimental — accuracy not yet measured
  • A high pyrolysis temperature produces a graphite-like structure with high electrical conductivity, which is favorable for biochar application as an EDLC.

    “Besides, a high pyrolysis temperature produces a graphite-like structure with high electrical conductivity, which is also favorable for biochar application as an EDLC (Keiluweit et al. 2010; Rawat et al. 2022).”

    From Role of biochar toward carbon neutrality (2023) · cites this paper as Keiluweit et al. 2010

    The XRD and “Turbostratic char” sections report that higher charring temperatures produce increasingly ordered, graphene-like crystallites, and the latter mentions the electrical conductivity of chars. The paper describes these chars as poorly crystalline and distinct from graphite; it does not establish that higher temperature raises their conductivity or discuss their suitability for EDLCs. (LLM, conf=0.87)

    Experimental — accuracy not yet measured
  • A new peak at 43° appeared for samples pyrolyzed at 600 and 700 °C, indicating development of atomic order in increasingly carbonized material.

    “A new peak at 43 ◦ appeared for samples pyrolyzed at 600 and 700 ◦ C that indicated the development of atomic order in the increasingly carbonized material (Keiluweit et al., 2010).”

    From Effect of Pyrolysis Temperature on PhysicoChemical Properties and Acoustic-Based Amination of Biochar for Efficient CO2 Adsorption (2020) · cites this paper as Keiluweit et al., 2010

    The XRD section (page unavailable) says that peaks developing with further heating narrow as atomic order increases in carbonized plant material. The paper includes chars produced at 600 and 700 °C, but our copy describes the relevant peaks by spacings of about 0.381 and 0.207 nm, not as a new peak at 43°. (LLM, conf=0.86)

    Experimental — accuracy not yet measured
  • The greater the degree of formation of aromatic structures, the higher the resistance of the biochar to microbial degradation.

    “The greater the degree of formation of aromatic structures, the higher the resistance of the biochar to microbial degradation”

    From Biochar physicochemical properties: pyrolysis temperature and feedstock kind effects (2020) · cites this paper as Keiluweit et al. 2010

    The NEXAFS section (page unavailable) reports increasing aromatic condensation as charring temperature rises, and Comparison of Precursor Materials (page unavailable) reports reduced mineralization at higher temperatures for corn char. But that section reports no such temperature effect for oak char, while Environmental Implications ties resistance to biotic degradation to char chemistry and physical structure more broadly. The source therefore does not establish the claimed general rule that more aromatic structure always means greater resistance to microbial degradation. (LLM, conf=0.84)

    Experimental — accuracy not yet measured
  • Such low-temperature biochar also yields a greater recovery of C and other nutrients (feedstock dependent), which are usually lost at higher temperatures.

    “Such low-temperature biochar also yields a greater recovery of C and other nutrients (feedstock dependent), which are usually lost at higher temperatures (Keiluweit et al. 2010).”

    From Biochar physicochemical properties: pyrolysis temperature and feedstock kind effects (2020) · cites this paper as Keiluweit et al. 2010

    The Results and Discussion (page not specified) report that char yields decline as charring temperature rises, with different trends for wood and grass, supporting greater low-temperature recovery of char. The paper does not establish that other nutrients are usually lost at higher temperatures; it reports ash and nitrogen contents, but not their recovery as a group. (LLM, conf=0.84)

    Experimental — accuracy not yet measured

Self-check

Percentages, sums and reported differences re-computed from the paper’s own numbers.

The self-check needs the paper’s full text.

Cites

Flagged first, then by citations

Research works printed but not linked: 3

  1. Schenkel, Y. Modelisation des flux massiques et energetiques dans la carbonisation du bois en four Cornue. Ph.D. Dissertation, Gembloux, Belgium, 1999.
  2. Stöhr, J., NEXAFS spectroscopy. Springer: New York, 1996.
  3. Pastorova, I.; Botto, R. E.; Arisz, P.; Boon, J., Cellulose char structure -a combined s. 1994, 262(1), 27-47.

Cited by

Sorted by citations

Authors
Keiluweit, M., Nico, P. S., Johnson, M. G., & Kleber, M.
Affiliations
Environmental Protection Agency (US)
Corresponding author
Kleber, Markus
Venue
Environmental Science & Technology
Published
2010-01-25
Volume
44
Issue
4
Pages
1247-1253
ISSN
  • 0013-936X (ISSN-L)
  • 1520-5851
OpenAlex
W2050695214
Cited by
3,230
References
42
Citations by year
2026: 348 · 2025: 296 · 2024: 271 · 2023: 234 · 2022: 293 · 2021: 282 · 2020: 273 · 2019: 214 · 2018: 210 · 2017: 192 · 2016: 146 · 2015: 129 · 2014: 128 · 2013: 90 · 2012: 73
FWCI
39.72
Type
journal article
Language
en
Open access
Locations
  • Environmental Science & Technology (publishedVersion)
  • PubMed (publishedVersion)
  • OSTI OAI (U.S. Department of Energy Office of Scientific and Technical Information) (submittedVersion)
  • eScholarship (California Digital Library) (submittedVersion)
Funders
U.S. Department of Energy
Topics
  • Physical Sciences › Engineering › Biomedical Engineering › Thermochemical Biomass Conversion Processes
  • Life Sciences › Agricultural and Biological Sciences › Soil Science › Soil Carbon and Nitrogen Dynamics
  • Physical Sciences › Environmental Science › Water Science and Technology › Adsorption and biosorption for pollutant removal
Keywords
biochar, black carbon, biomass combustion, charring temperature, aromatic carbon, graphene, turbostratic graphite, amorphous carbon, wood, Poaceae, carbon sequestration
MeSH terms
Charcoal, Plants, Temperature, X-Ray Diffraction, Spectroscopy, Fourier Transform Infrared

About these checks

Registry, retraction, Cites and statistics results are computed, not judged, with one exception: a printed reference that no index lists is read once by a model before it counts as a citation error. Claims are extracted by a model and kept only when their quote appears verbatim in the text; each cited source is then checked, with a model’s help, for whether it says what the claim relies on. Those verdicts can be wrong — read the claim’s quote and the cited source before relying on one.

Statistics and arithmetic are recomputed, not judged.

Confidence bands are shown only for fields calibrated on our annotated test set. None is calibrated yet, so no band is shown.

What counts as a claim ›How we measure confidence ›How we check this ›

Are you an author, or do you see a problem with this page? Request a review