title: Organic compounds leached from fast pyrolysis mallee leaf and bark biochars.
abstract: Characterization of organic compounds leached from biochars is essential in assessing the possible toxicity of the biochar to the soils' biota. In this study the nature of the leached organic compounds from Mallee biochars, produced from pyrolysis of Mallee leaf and bark in a fluidised-bed pyrolyser at 400 and 580°C was investigated. Light bio-oil compounds and aromatic organic compounds were investigated. The 'bio-oil like' light compounds from leaf and bark biochars 'surfaces were obtained after leaching the chars with a solvent, suitable to dissolve the respective bio-oils. GC/MS was implemented to investigate the leachates. Phenolics, which are potentially harmful toxins, were detected and their concentration shown to be dependent on the char's origin and the char production temperature. Further, to simulate biochars amendment to soils, the chars were leached with water. The water-leached aromatic compounds from leaf and bark biochars were characterized using UV-fluorescence spectroscopy. Those results suggested that biochars contain leachable compounds of which the nature and amount is dependent on the biomass feedstock, pyrolysis temperature and leaching time.
authors.affiliation: Fuels and Energy Technology Institute, Curtin University of Technology, GPO Box U1987, Perth, WA 6845, Australia. Electronic address: C.Lievens@UTwente.nl.
authors.forename: Caroline
authors.initials: C
authors.lastname: Lievens
authors.affiliation: Fuels and Energy Technology Institute, Curtin University of Technology, GPO Box U1987, Perth, WA 6845, Australia.
authors.forename: Daniel
authors.initials: D
authors.lastname: Mourant
authors.affiliation: Fuels and Energy Technology Institute, Curtin University of Technology, GPO Box U1987, Perth, WA 6845, Australia.
authors.forename: Richard
authors.initials: R
authors.lastname: Gunawan
authors.affiliation: Fuels and Energy Technology Institute, Curtin University of Technology, GPO Box U1987, Perth, WA 6845, Australia.
authors.forename: Xun
authors.initials: X
authors.lastname: Hu
authors.affiliation: Fuels and Energy Technology Institute, Curtin University of Technology, GPO Box U1987, Perth, WA 6845, Australia.
authors.forename: Yi
authors.initials: Y
authors.lastname: Wang
mesh_terms: D018533:Biomass; D002606:Charcoal / Q000737:chemistry*; D005052:Eucalyptus / Q000737:chemistry*; D008401:Gas Chromatography-Mass Spectrometry; D007700:Kinetics; D009821:Oils / Q000737:chemistry; D009930:Organic Chemicals / Q000737:chemistry*; D024301:Plant Bark / Q000737:chemistry*; D018515:Plant Leaves / Q000737:chemistry*; D013696:Temperature
chemical_list: D009821:Oils; D009930:Organic Chemicals; C540010:biochar; D002606:Charcoal
keywords: Biochar; GC/MS; Leaching; Organic matter; UV-fluorescence