skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Black Carbon Increases Cation Exchange Capcity in Soils

Abstract

Black Carbon (BC) may significantly affect nutrient retention and play a key role in a wide range of biogeochemical processes in soils, especially for nutrient cycling. Anthrosols from the Brazilian Amazon (ages between 600 and 8700 yr BP) with high contents of biomass-derived BC had greater potential cation exchange capacity (CEC measured at pH 7) per unit organic C than adjacent soils with low BC contents. Synchrotron-based near edge X-ray absorption fine structure (NEXAFS) spectroscopy coupled with scanning transmission X-ray microscopy (STXM) techniques explained the source of the higher surface charge of BC compared with non-BC by mapping cross-sectional areas of BC particles with diameters of 10 to 50 {micro}m for C forms. The largest cross-sectional areas consisted of highly aromatic or only slightly oxidized organic C most likely originating from the BC itself with a characteristic peak at 286.1 eV, which could not be found in humic substance extracts, bacteria or fungi. Oxidation significantly increased from the core of BC particles to their surfaces as shown by the ratio of carboxyl-C/aromatic-C. Spotted and non-continuous distribution patterns of highly oxidized C functional groups with distinctly different chemical signatures on BC particle surfaces (peak shift at 286.1 eV to a highermore » energy of 286.7 eV) indicated that non-BC may be adsorbed on the surfaces of BC particles creating highly oxidized surface. As a consequence of both oxidation of the BC particles themselves and adsorption of organic matter to BC surfaces, the charge density (potential CEC per unit surface area) was greater in BC-rich Anthrosols than adjacent soils. Additionally, a high specific surface area was attributable to the presence of BC, which may contribute to the high CEC found in soils that are rich in BC.« less

Authors:
; ; ; ; ; ; ; ; ;
Publication Date:
Research Org.:
Brookhaven National Laboratory (BNL) National Synchrotron Light Source
Sponsoring Org.:
Doe - Office Of Science
OSTI Identifier:
913988
Report Number(s):
BNL-78556-2007-JA
Journal ID: ISSN 0361-5995; SSSJD4; TRN: US0801455
DOE Contract Number:
DE-AC02-98CH10886
Resource Type:
Journal Article
Resource Relation:
Journal Name: Soil Sci. Soc. Am. J.; Journal Volume: 70
Country of Publication:
United States
Language:
English
Subject:
43 PARTICLE ACCELERATORS; CARBON; CATIONS; CHARGE DENSITY; FINE STRUCTURE; ION EXCHANGE; ORGANIC MATTER; SOILS; SPECIFIC SURFACE AREA; SURFACE AREA; NSLS; national synchrotron light source

Citation Formats

Liang,B., Lehmann, J., Solomon, D., Kinyangi, J., Grossman, J., ONeill, B., Skjemstad, J., Thies, J., Luizao, F., and et al.. Black Carbon Increases Cation Exchange Capcity in Soils. United States: N. p., 2006. Web. doi:10.2136/sssaj2005.0383.
Liang,B., Lehmann, J., Solomon, D., Kinyangi, J., Grossman, J., ONeill, B., Skjemstad, J., Thies, J., Luizao, F., & et al.. Black Carbon Increases Cation Exchange Capcity in Soils. United States. doi:10.2136/sssaj2005.0383.
Liang,B., Lehmann, J., Solomon, D., Kinyangi, J., Grossman, J., ONeill, B., Skjemstad, J., Thies, J., Luizao, F., and et al.. Sun . "Black Carbon Increases Cation Exchange Capcity in Soils". United States. doi:10.2136/sssaj2005.0383.
@article{osti_913988,
title = {Black Carbon Increases Cation Exchange Capcity in Soils},
author = {Liang,B. and Lehmann, J. and Solomon, D. and Kinyangi, J. and Grossman, J. and ONeill, B. and Skjemstad, J. and Thies, J. and Luizao, F. and et al.},
abstractNote = {Black Carbon (BC) may significantly affect nutrient retention and play a key role in a wide range of biogeochemical processes in soils, especially for nutrient cycling. Anthrosols from the Brazilian Amazon (ages between 600 and 8700 yr BP) with high contents of biomass-derived BC had greater potential cation exchange capacity (CEC measured at pH 7) per unit organic C than adjacent soils with low BC contents. Synchrotron-based near edge X-ray absorption fine structure (NEXAFS) spectroscopy coupled with scanning transmission X-ray microscopy (STXM) techniques explained the source of the higher surface charge of BC compared with non-BC by mapping cross-sectional areas of BC particles with diameters of 10 to 50 {micro}m for C forms. The largest cross-sectional areas consisted of highly aromatic or only slightly oxidized organic C most likely originating from the BC itself with a characteristic peak at 286.1 eV, which could not be found in humic substance extracts, bacteria or fungi. Oxidation significantly increased from the core of BC particles to their surfaces as shown by the ratio of carboxyl-C/aromatic-C. Spotted and non-continuous distribution patterns of highly oxidized C functional groups with distinctly different chemical signatures on BC particle surfaces (peak shift at 286.1 eV to a higher energy of 286.7 eV) indicated that non-BC may be adsorbed on the surfaces of BC particles creating highly oxidized surface. As a consequence of both oxidation of the BC particles themselves and adsorption of organic matter to BC surfaces, the charge density (potential CEC per unit surface area) was greater in BC-rich Anthrosols than adjacent soils. Additionally, a high specific surface area was attributable to the presence of BC, which may contribute to the high CEC found in soils that are rich in BC.},
doi = {10.2136/sssaj2005.0383},
journal = {Soil Sci. Soc. Am. J.},
number = ,
volume = 70,
place = {United States},
year = {Sun Jan 01 00:00:00 EST 2006},
month = {Sun Jan 01 00:00:00 EST 2006}
}
  • The impact of absorbing aerosols on global climate are not completely understood. Here, we present results of idealized experiments conducted with the Community Atmosphere Model (CAM4) coupled to a slab ocean model (CAM4-SOM) to simulate the climate response to increases in tropospheric black carbon aerosols (BC) by direct and semi-direct effects. CAM4-SOM was forced with 0, 1x, 2x, 5x and 10x an estimate of the present day concentration of BC while maintaining their estimated present day global spatial and vertical distribution. The top of the atmosphere (TOA) radiative forcing of BC in these experiments is positive (warming) and increases linearly as the BC burden increases. The total semi-direct effect for the 1x experiment is positive but becomes increasingly negative for higher BC concentrations. The global average surface temperature response is found to be a linear function of the TOA radiative forcing. The climate sensitivity to BC from these experiments is estimated to be 0.42 Kmore » $$ W^{-1} m^{2}$$ when the semi-direct effects are accounted for and 0.22 K $$ W^{-1} m^{2}$$ with only the direct effects considered. Global average precipitation decreases linearly as BC increases, with a precipitation sensitivity to atmospheric absorption of 0.4 $$\%$$ $$W^{-1}m^{2}$$ . The hemispheric asymmetry of BC also causes an increase in southward cross-equatorial heat transport and a resulting northward shift of the inter-tropical convergence zone in the simulations at a rate of 4$$^{\circ}$$N $$ PW^{-1}$$. Global average mid- and high-level clouds decrease, whereas the low-level clouds increase linearly with BC. The increase in marine stratocumulus cloud fraction over the south tropical Atlantic is caused by increased BC-induced diabatic heating of the free troposphere.« less
  • Cited by 1
  • The aim of this work was to investigate changes in molecular form and surface charge of black carbon (BC) due to longtermnatural oxidation and to examine how climatic and soil factors affect BC oxidation. Black C was collected from 11 historical charcoal blast furnace sites with a geographic distribution from Quebec, Canada, to Georgia, USA, and compared to BC that was newly produced (new BC) using rebuilt historical kilns. The results showed that the historical BC samples were substantially oxidized after 130 years in soils as compared to new BC or BC incubated for one year. The major alterations bymore » natural oxidation of BC included: (1) changes in elemental composition with increases in oxygen (O) from 7.2% in new BC to 24.8% in historical BC and decreases in C from 90.8% to 70.5%; (2) formation of oxygen-containing functional groups, particularly carboxylic and phenolic functional groups, and (3) disappearance of surface positive charge and evolution of surface negative charge after 12 months of incubation. Although time of exposure significantly increased natural oxidation of BC, a significant positive relationship between mean annual temperature (MAT) and BC oxidation (O/C ratio with r = 0.83;P < 0.01) explained that BC oxidation was increased by 87 mmole kg C -1 per unit Celsius increase in MAT. This long-term oxidation was more pronounced on BC surfaces than for entire particles, and responded 7-fold stronger to increases in MAT. Our results also indicated that oxidation of BC was more important than adsorption of non-BC. Thus, natural oxidation of BC may play an important role in the effects of BC on soil biogeochemistry.« less