Black Carbon In Soil Organic And Mineral Matter

Other Titles
Black carbon (BC) is considered ubiquitous in soil organic matter and therefore plays an important role in soil biogeochemistry. This research largely relied on advanced Near-edge X-ray absorption fine-edge (NEXAFS) spectroscopy to expand our understanding of black carbon chemistry, and to investigate the mechanisms controlling black carbon stability in soil. The international BC ring trial was characterized using NEXAFS; our results indicated that NEXAFS is a reliable approach for spectroscopic characterization of BC in soil. We also evaluated two mathematical modeling approaches to quantify black carbon (BC) in a BC-rich Anthrosol using carbon (C) near-edge X-ray absorption fine-edge structure (NEXAFS) spectroscopy. Best fit results (lowest error) were achieved using BCs formed at 500[MASCULINE ORDINAL INDICATOR]C-600[MASCULINE ORDINAL INDICATOR]C compared with BC produced at at 350[MASCULINE ORDINAL INDICATOR]C-450[MASCULINE ORDINAL INDICATOR]C. BC produced at lower temperatures were characterized by lower aromaticity than those produced at higher temperatures. These differences suggest that assumptions about formation temperature of BC may affect the quantification of BC contained in soil for methods that rely on reference materials. We attempted to verify the existence of BC HS using Scanning Transmission X -ray Microscopy (STXM) coupled with near-edge X-ray absorption fine-edge spectroscopy (NEXAFS) spectroscopy to analyze the spatial composition of a BC rich soil microaggregate at a scale of < 50 [MICRO SIGN]m. However, we were unable to obtain a good fit (RMS = <0.01) for the HS extracts within the spatial map. Our results suggest that HS do not exist in soil as a distinct component class but rather reflect the extraction of various materials at different stages of decomposition. Near-edge X-ray absorption fine-edge spectroscopy (NEXAFS), scanning electron microscopy (SEM) and scanning transmission electron microscopy (STEM) were used to compare BC exposed to water, nitric acid (HNO3), kaolinite, pyrophyllite, vermiculite and goethite. that multiple mechanisms such as electrostatic interactions, ligand exchange, electron donor or acid-base reactions play a role in the interaction between BC and clay minerals. High-resolution microscopy revealed that BC-mineral interactions can commence quickly and result in chemical changes to BC.
Journal / Series
Volume & Issue
Date Issued
black carbon; soil; nexafs spectroscopy
Effective Date
Expiration Date
Union Local
Number of Workers
Committee Chair
Lehmann, Christopher Johannes
Committee Co-Chair
Committee Member
Thies, Janice E.
Duxbury, John M
Degree Discipline
Soil and Crop Sciences
Degree Name
Ph. D., Soil and Crop Sciences
Degree Level
Doctor of Philosophy
Related Version
Related DOI
Related To
Related Part
Based on Related Item
Has Other Format(s)
Part of Related Item
Related To
Related Publication(s)
Link(s) to Related Publication(s)
Link(s) to Reference(s)
Previously Published As
Government Document
Other Identifiers
Rights URI
dissertation or thesis
Accessibility Feature
Accessibility Hazard
Accessibility Summary
Link(s) to Catalog Record