Quantitative characterization of pore structure of several biochars with 3D imaging.
Pore space characteristics of biochars may vary depending on the used raw material and processing technology. Pore structure has significant effects on the water retention properties of biochar amended soils. In this work, several biochars were characterized with three-dimensional imaging and image analysis. X-ray computed microtomography was used to image biochars at resolution of 1.14 μm and the obtained images were analysed for porosity, pore size distribution, specific surface area and structural anisotropy. In addition, random walk simulations were used to relate structural anisotropy to diffusive transport. Image analysis showed that considerable part of the biochar volume consist of pores in size range relevant to hydrological processes and storage of plant available water. Porosity and pore size distribution were found to depend on the biochar type and the structural anisotopy analysis showed that used raw material considerably affects the pore characteristics at micrometre scale. Therefore, attention should be paid to raw material selection and quality in applications requiring optimized pore structure.
Natural Resources Institute Finland (Luke), FI-31600, Jokioinen, Finland. jari.hyvaluoma@luke.fi.
Jari
http://orcid.org/0000-0003-1113-439X
J
Hyväluoma
Natural Resources Institute Finland (Luke), FI-31600, Jokioinen, Finland.
Sampo
S
Kulju
BioMediTech Institute and Faculty of Biomedical Sciences and Engineering, Tampere University of Technology, Tampere, Finland.
Markus
M
Hannula
VTT Technical Research Centre of Finland Ltd., P.O.Box 1000, FI-02044, VTT, Espoo, Finland.
Hanne
H
Wikberg
VTT Technical Research Centre of Finland Ltd., P.O.Box 1000, FI-02044, VTT, Espoo, Finland.
Anssi
A
Källi
Natural Resources Institute Finland (Luke), FI-31600, Jokioinen, Finland.
Kimmo
K
Rasa
D002606:Charcoal; D004058:Diffusion; D007091:Image Processing, Computer-Assisted; D021621:Imaging, Three-Dimensional; D016062:Porosity; D014867:Water / Q000737:chemistry
C540010:biochar; D014867:Water; D002606:Charcoal
Biochar; Image analysis; Pore structure; Soil amendment; Water retention; X-ray tomography