Aqueous Leaching of Organic Acids and Dissolved Organic Carbon from Various Biochars Prepared at Different Temperatures
- 1 March 2015
- journal article
- Published by Wiley in Journal of Environmental Quality
- Vol. 44 (2), 684-695
- https://doi.org/10.2134/jeq2014.08.0341
Abstract
Biochar has been used as a soil amendment, as a water treatment material, and for carbon (C) sequestration. Thirty-six biochars, produced from wood, agricultural residue, and manure feedstocks at different temperatures, were evaluated for the aqueous leaching of different forms of soluble C. The release of inorganic C (alkalinity), organic acids (OAs), and total dissolved organic C (DOC) was highly variable and dependent on the feedstock and pyrolysis temperature. The pH and alkalinity increased for the majority of samples. Higher pH values were associated with high-temperature (high-T) (600 and 700°C) biochars. Statistically significant differences in alkalinity were not observed between low-temperature (low-T) (300°C) and high-T biochars, whereas alkalinity released from wood-based biochar was significantly lower than from others. Concentrations of OAs and DOC released from low-T biochars were greater than from high-T biochars. The C in the OAs represented 1 to 60% of the total DOC released, indicating the presence of other DOC forms. The C released as DOC represented up to 3% (majority <0.1%) of the total C in the biochar. Scanning electron microscopy with energy dispersive X-ray spectroscopy showed the high-T biochars had a greater proportion of micropores. Fourier transform infrared spectroscopy showed that hydroxyl, aliphatic, and quinone were the predominant functional groups of all biochars and that the abundance of other functional groups was dependent on the feedstock. The release of DOC, especially bioavailable forms such as OAs, may promote growth of organisms and heavy metal complexation and diminish the potential effectiveness of various biochars for C sequestration.Keywords
Funding Information
- Natural Sciences and Engineering Research Council of Canada
This publication has 41 references indexed in Scilit:
- Global Charcoal Mobilization from Soils via Dissolution and Riverine Transport to the OceansScience, 2013
- Biochar effects on soil biota – A reviewSoil Biology and Biochemistry, 2011
- Short-term biochar-induced increase in soil CO2 release is both biotically and abiotically mediatedSoil Biology and Biochemistry, 2011
- Pelleted biochar: Chemical and physical properties show potential use as a substrate in container nurseriesBiomass and Bioenergy, 2011
- Characterisation of aquatic humic and non-humic matter with size-exclusion chromatography – organic carbon detection – organic nitrogen detection (LC-OCD-OND)Water Research, 2011
- Properties of dairy-manure-derived biochar pertinent to its potential use in remediationBioresource Technology, 2010
- Abiotic and Microbial Oxidation of Laboratory-Produced Black Carbon (Biochar)Environmental Science & Technology, 2010
- Black carbon decomposition and incorporation into soil microbial biomass estimated by 14C labelingSoil Biology and Biochemistry, 2009
- Characteristics of hemicellulose, cellulose and lignin pyrolysisFuel, 2007
- A handful of carbonNature, 2007