Chemical characterization of rice straw-derived biochar for soil amendment

Published Date

December 2012, Vol.47:268–276, doi:10.1016/j.biombioe.2012.09.034

Title 

Chemical characterization of rice straw-derived biochar for soil amendment

• Author 

• Weixiang Wu ^a,,
• Min Yang ^a
• Qibo Feng ^a
• Kim McGrouther ^b
• Hailong Wang ^b,c
• Haohao Lu ^a
• Yingxu Chen ^a

• aMinistry of Agriculture Key Laboratory of Non-point Source Pollution Control, Institute of Environmental Science and Technology, Zhejiang University, 866 Yuhangtang Road, Hangzhou 310058, PR China
• bScion, Private Bag 3020, Rotorua 3046, New Zealand
• cSchool of Environmental and Resource Sciences, Zhejiang A & F University, Lin’an, Hangzhou 311300, PR China

Received 16 December 2011. Revised 15 June 2012. Accepted 12 September 2012. Available online 6 October 2012.

Abstract

Pyrolysis of rice straw to create biochar for soil amendment appears to be a promising method to address concerns with regard to improving soil fertility, increasing Carbon storage and decreasing Green House Gas emissions. However, the ability of rice straw-derived biochar to affect these factors might vary depending on its characteristics. It is therefore essential to investigate the properties before large-scale application of rice straw-derived biochar. In this study, rice straw-derived biochars produced at different temperatures (300, 400, 500, 600 & 700 °C) and residence time (1, 2, 3 & 5 h) were characterized using a suite of analytical techniques. Results showed that pyrolysis temperature had a greater influence than residence time on the chemical composition and structure of rice straw-derived biochar produced at low heating rate. The rice straw-derived biochars especially produced at 400 °C had high alkalinity and cation exchange capacity, and high levels of available phosphorus and extractable cations. These properties indicate potential application of rice straw-derived biochar as a fertilizer and soil amendment. Fourier transform infrared spectra showed that higher pyrolysis temperatures promote condensation reactions. Rice straw-derived biochars contained turbostratic crystallites at 400 °C, and displayed a high level of aromatization at 500 °C. Increasing charring temperature will increase the aromaticity of biochar, and might include its recalcitrance.

Highlights

► Pyrolysis temperature played a significant role in rice straw biochar properties. ► Rice straw biochars had high alkalinity, cation exchange capacity and available P. ► Rice straw biochar yielded at 400 °C might be more suitable for soil amendment. ► Rice straw biochar displayed a high level of aromatization at 500  C.

Keywords

• Rice straw
• Characterization
• Biochar
• Pyrolysis condition
• Stability

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• ∗ 
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