Effects of Mineral Additives on Biochar Formation: Carbon Retention, Stability, and Properties

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• 作者：Feiyue Li ; Xinde Cao ; Ling Zhao ; Jianfei Wang ; Zhenliang Ding
• 刊名：Environmental Science & Technology
• 出版年：2014
• 出版时间：October 7, 2014
• 年：2014
• 卷：48
• 期：19
• 页码：11211-11217
• 全文大小：311K
• ISSN：1520-5851

文摘

Biochar is being recognized as a promising tool for long-term carbon sequestration, and biochar with high carbon retention and strong stability is supposed to be explored for that purpose. In this study, three minerals, including kaolin, calcite (CaCO₃), and calcium dihydrogen phosphate [Ca(H₂PO₄)₂], were added to rice straw feedstock at the ratio of 20% (w/w) for biochar formation through pyrolysis treatment, aiming to improve carbon retention and stabilization in biochar. Kaolin and CaCO₃ had little effect on the carbon retention, whereas Ca(H₂PO₄)₂ increased the carbon retention by up to 29% compared to untreated biochar. Although the carbon loss from the kaolin-modified biochar with hydrogen peroxide oxidation was enhanced, CaCO₃ and Ca(H₂PO₄)₂ modification reduced the carbon loss by 18.6 and 58.5%, respectively. Moreover, all three minerals reduced carbon loss of biochar with potassium dichromate oxidation from 0.3 to 38.8%. The microbial mineralization as CO₂ emission in all three modified biochars was reduced by 22.2鈥?8.7% under aerobic incubation and 5鈥?1% under anaerobic incubation. Enhanced carbon retention and stability of biochar with mineral treatment might be caused by the enhanced formation of aromatic C, which was evidenced by cross-polarization magic angle spinning ¹³C nuclear magnetic resonance spectra and Fourier transform infrared spectroscopy analysis. Our results indicated that the three minerals, especially Ca(H₂PO₄)₂, were effective in increasing carbon retention and strengthening biochar stabilization, which provided a novel idea that people could explore and produce the designated biochar with high carbon sequestration capacity and stability.