title: Structure-mechanics property relationship of waste derived biochars.
abstract: The widespread applications of biochar in agriculture and environmental remediation made the scientific community ignore its mechanical properties. Hence, to examine the scope of biochar's structural applications, its mechanical properties have been investigated in this paper through nanoindentation technique. Seven waste derived biochars, made under different pyrolysis conditions and from diverse feedstocks, were studied via nanoindentation, infrared spectroscopy, X-ray crystallography, thermogravimetry, and electron microscopy. Following this, an attempt was made to correlate the biochars' hardness/modulus with reaction conditions and their chemical properties. The pine wood biochar made at 900°C and 60min residence time was found to have the highest hardness and elastic modulus of 4.29 and 25.01GPa, respectively. It was shown that a combination of higher heat treatment (≥500°C) temperature and longer residence time (~60min) increases the values of hardness and modulus. It was further realized that pyrolysis temperature was a more dominant factor than residence time in determining the final mechanical properties of biochar particles. The degree of aromaticity and crystallinity of the biochar were also correlated with higher values of hardness and modulus.
authors: Department of Civil and Environmental Engineering, University of Auckland, Auckland 1142, New Zealand. Electronic address: odas566@aucklanduni.ac.nz.
authors: Oisik
authors: O
authors: Das
authors: Department of Civil and Environmental Engineering, University of Auckland, Auckland 1142, New Zealand. Electronic address: a.sarmah@auckland.ac.nz.
authors: Ajit K
authors: AK
authors: Sarmah
authors: Department of Mechanical Engineering, Center for Advanced Composite Materials, University of Auckland, Auckland 1142, New Zealand. Electronic address: d.bhattacharyya@auckland.ac.nz.
authors: Debes
authors: D
authors: Bhattacharyya
keywords: Biomass; Hardness; Mechanical; Modulus; Pyrolysis; Waste