title: Effect of pH on surface characteristics of switchgrass-derived biochars produced by fast pyrolysis.
abstract: Surface properties of switchgrass-derived biochars produced at fast pyrolysis temperatures of 450, 600 and 800 °C were characterized at different solution pHs in order to determine the structural and chemical changes of artificially-weathered biochars when incorporated into soil. As biochars were acidified from pH 7 to 3, crystalline minerals dissolved slowly releasing nutrients; however, residual minerals were still detected in biochars produced at higher pyrolysis temperatures after pH treatment. Moreover, the amount of exchangeable bases and other inorganic compounds released from the biochars increased when pH decreased. As minerals dissolved from the biochars, total surface area and pore volume were found to increase. Surface functional groups and water vapor adsorption capacity at 0.8 P/Po also increased, whereas the potential CEC of biochars decreased due to the replacement of exchangeable sites by hydrogen ion. Therefore, during the aging process, it is predicted that soil-incorporated biochars will slowly release nutrients with changes in surface functionality and porosity, which are expected to enhance water holding capacity of soil and provide a beneficial habitat for microbial colonization.
authors.affiliation: Center for Renewable Carbon, 2506 Jacob Drive, University of Tennessee, Knoxville, TN 37996, United States.
authors.forename: Pyoungchung
authors.initials: P
authors.lastname: Kim
authors.affiliation: Department of Biosystems Engineering & Soil Science, 2506 E.J. Chapman Dr., University of Tennessee, Knoxville, TN 37996, United States.
authors.forename: Amy M
authors.initials: AM
authors.lastname: Johnson
authors.affiliation: Department of Biosystems Engineering & Soil Science, 2506 E.J. Chapman Dr., University of Tennessee, Knoxville, TN 37996, United States.
authors.forename: Michael E
authors.initials: ME
authors.lastname: Essington
authors.affiliation: Department of Biosystems Engineering & Soil Science, 2506 E.J. Chapman Dr., University of Tennessee, Knoxville, TN 37996, United States.
authors.forename: Mark
authors.initials: M
authors.lastname: Radosevich
authors.affiliation: Korea Institute of Ceramic Engineering & Technology, Seoul 153-801, South Korea.
authors.forename: Woo-Tech
authors.initials: WT
authors.lastname: Kwon
authors.affiliation: Department of Forest Biomaterials Engineering, Kangwon National University, Chunchen 200-701, South Korea.
authors.forename: Seung-Hwan
authors.initials: SH
authors.lastname: Lee
authors.affiliation: Center for Renewable Carbon, 2506 Jacob Drive, University of Tennessee, Knoxville, TN 37996, United States.
authors.forename: Timothy G
authors.initials: TG
authors.lastname: Rials
authors.affiliation: Center for Renewable Carbon, 2506 Jacob Drive, University of Tennessee, Knoxville, TN 37996, United States. Electronic address: nlabbe@utk.edu.
authors.forename: Nicole
authors.initials: N
authors.lastname: Labbé
mesh_terms: D000327:Adsorption; D002606:Charcoal / Q000737:chemistry*; D005740:Gases / Q000737:chemistry; D006358:Hot Temperature; D006863:Hydrogen-Ion Concentration; D008903:Minerals / Q000737:chemistry; D025341:Principal Component Analysis; D012987:Soil / Q000737:chemistry; D017550:Spectroscopy, Fourier Transform Infrared; D013499:Surface Properties; D014867:Water / Q000737:chemistry
chemical_list: D005740:Gases; D008903:Minerals; D012987:Soil; C540010:biochar; D014867:Water; D002606:Charcoal