Dynamic molecular structure of plant biomass-derived black carbon (biochar).

By M. Keiluweit, P. Nico, Mark G. Johnson, M. Kleber. Environmental Science and Technology, 2010

2,906 citations recorded by the source corpus.

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.

Subfields: Biomedical Engineering, Inorganic Chemistry, Materials Chemistry

View Paper: https://www.semanticscholar.org/paper/2fb1ab85f99ee1f2aa57b366946eb5084d329661

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Citations in the corpus

Biochar effects on soil biota – A review (2011, background): “This fused aromatic structure of biochars in itself can have varying forms, including amorphous C, which is dominant at lower pyrolysis temperatures, and turbostratic C, which forms at higher temperatures (Keiluweit et al., 2010; Nguyen et al., 2010).”
Aromaticity and degree of aromatic condensation of char (2015, methodology): “…time at HTT with continuous N2 flow; B, 1 h residence time at HTT in a closed chamber) were used to create 38 laboratory char samples with HTT between 100 and 1000 C (A, 200–1000 C; B, 100–700 C), as reported in detail in two previous studies (Keiluweit et al., 2010; Schneider et al., 2011).”
Distributed biochar and bioenergy coproduction: a regionally specific case study of environmental benefits and economic impacts (2013, background): “, 2011), resulting in chars with different chemical properties (Brewer et al., 2009; Keiluweit et al., 2010) and associated differences in recalcitrance (Spokas, 2010), agronomic performance (Atkinson et al.”
Biochar: a synthesis of its agronomic impact beyond carbon sequestration. (2012, background): “When biochar is produced at higher pyrolysis temperatures (400–700°C), its carbon is distributed in more polycondensed aromatic structures (Keiluweit et al., 2010).”
Electrosorption on activated biochar: effect of thermo-chemical activation treatment on the electric double layer capacitance (2013, background): “The latter peak is typically observed in ordered turbostratic carbon crystallites [34, 35, 39, 40].”
Influence of Pyrolysis Temperature on Cadmium and Zinc Sorption Capacity of Sugar Cane Straw–Derived Biochar (2013, result): “This is in agreement with the findings of Kim et al. (2013), which observed that biochar produced from a giant Miscanthus at higher pyrolytic temperatures (≥ 500 °C) increased the sorption of Cd from aqueous solution up to 13.24 mg g -1 (≈ 59 mmol kg -1 ) and they attributed the results due to the…”
Influence of Carbonization Temperature on Physicochemical Properties of Biochar derived from Slow Pyrolysis of Durian Wood (Durio zibethinus) Sawdust (2016, positive): “A similar observation was reported earlier for preparation of graphitic black carbon, switch grass, and pine wood biochar (Schmidt and Noack 2000; Kim et al. 2011).”